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, Available online , doi: 10.12403/j.1001-1498.20230079
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Objective To clarify the pathogen causing black spot disease on Lonicera japonica, and to provide a theoretical basis for effective prevention and control of this disease. Method The strains of the pathogen were isolated by conventional tissue plate method, and were identified by the morphological characters and phylogenetic analysis of ITS, gpd and EF-1α sequences. Its pathogenicity was tested through in vitro inoculating healthy leaves of Lonicera japonica and Solanum lycopersicum. Result The isolated fungal strain YP4 morphologically formed greyish to yellowish white, cottony colonies on Potato Dextrose Agar, which were consistent with published descriptions of Stemphylium lycopersici. In the three phylogenetic trees based on of ITS, gpd and EF-1α sequences, the isolate YP4 fell into the Stemphylium lycopersici clade with strong support. Based on the pathogenicity measurement of Koch's rule, the strain YP4 was pathogenic to leaves of Lonicera japonica and Solanum lycopersicum. Conclusion Combined with the morphological characteristics, the pathogenicity determination and phylogenetic analysis of ITS, gpd and EF-1α sequences, the pathogen causing black spot disease on honeysuckle is identified as Stemphylium lycopersici. To our knowledge, this is the first report of S. lycopersici causing black spot of Lonicera japonica in China.
, Available online , doi: 10.12403/j.1001-1498.20230039
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Objective The invasion of Solenopsis invicta has caused serious ecological problems, and temperature is the key factor limiting the invasion and development of S. invicta. This study investigated the ant communities in different habitats in Kunming, Yunnan Province, to reveal the influence of S. invicta on local ant communities in sub-suitable areas. Methods In June and August 2021, based on five habitats in Hongqiao Road and Shalang, Kunming City, Yunnan Province, the ant communities in the different habitats were surveyed by pitfall traps, and the relationship between the local ant communities and the occurrence of S. invicta was analyzed. Results The thinning and prediction curves based on the ant individuals in five habitats were smooth and the sampling was sufficient; A total of 2 748 ants were collected from 5 habitats, belonging to 4 subfamilies, 19 genera and 34 species, of which 1 920 were S. invicta; the individual number of S. invicta collected from eucalyptus forest was the highest (99.2%), followed by wasteland (HW 94.2%, LW 90.7%), and the ecotone between Pinus yunnanensis secondary forest and wasteland had the lowest number of S. invicta collected (44.7%); S. invicta was not collected in P. yunnanensis secondary forest. Only 1 species of native ants was collected in the eucalypt forest, 3 species and 7 species were collected in the wasteland, and 15 species were collected in the ecotone. The species richness and Chao-1 estimate of ants in P. yunnanensis secondary forest and ecotone were significantly higher than those in eucalyptus forest, while the dominance index was significantly lower than that in eucalyptus forest. The similarity of ant community structure in five habitats was significantly different, and the ant community structure in habitats where S. invicta occurred was not similar with that in P. yunnanensis secondary forest; There was no significant correlation between nest density and abundance, local ant abundance and species richness of S. invicta. As the abundance of S. invicta increased, the species richness and abundance of local ants decreased linearly. Conclusion In the sub-suitable area of S. invicta in Kunming, S. invicta mostly occurs in disturbed open habitats, especially in eucalypt forests, but rarely invades habitats with high canopy density; After the invasion of S. invicta, the diversity level of the local ant community decreases significantly and the ant community structure changes; After the invasion of S. invicta, it is necessary for the population to develop to a large scale to show the population quantity advantage, and a small number of local ants can coexist with it during the population development; Reducing the suitable habitats of S. invicta, strengthening the inspection of suitable habitats, and carrying out chemical treatment on medium and large ant nests in time will help reduce the occurrence and development of S. invicta.
, Available online , doi: 10.12403/j.1001-1498.20230012
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Objective To Investigate the defensive response to walnut fruit husk after Cydia pomonella infestation. Method UV Spectrophotometry and Microplate Reader were used to analyze nutrient substances, secondary metabolites content, defense enzyme activity and interaction between Cydia pomonella and walnut Result The content of soluble sugar and soluble protein decreased gradually over time after the walnut husk was eaten by C. pomonella. The soluble protein content at 24 h of damage was significantly different from the control (P>0.05); There was a significant difference between the soluble sugar and the control at 48 hours of damage (P>0.05). The contents of secondary metabolites juglone and tannin increased first and then decreased. Among them, the content of juglone quinone reached the highest at 48 h, which was 976.68 µg·g−1 FW, and was 1.44 times that of the control; The tannin content reached a peak at 24 h at 4.11 mg·g−1, which was 1.33 times that of the control; The content of flavonoids showed a gradual upward trend, and the difference was significant compared with the control at 24 h (P>0.05). At 12 h of damage, there was a significant difference in CAT activity compared with the control (P>0.05). At 72 h, the CAT activity peaked at 55.97 U·min−1·g−1, which was 1.45 times that of the control; The POD activity showed a trend of first decreasing and then increasing. At 72 h, the POD activity reached the highest value, which was 1.62 times that of the control; The SOD activity increased firts and then decreased. At 24 h, the SOD activity reached a peak value of 623.69 U·g−1, which was 1.98 times that of the control. Conclusion The walnut fruit husk mainly produces a stress response to the damage of C. pomonella by regulating the changes of nutrients, secondary metabolites and defense enzyme activities in the body, and then plays a defensive role.
, Available online , doi: 10.12403/j.1001-1498.20230060
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Objective To explore the application of morphometry in the classification of Formicidae. Methods Factor analysis, principal component analysis and systematic clustering statistical analysis were used to study the morphometric characteristics of 19 species of ants from the genus Aphaenogaster in China. Results The four principal components, including thorax length (MSL), head width (HW), petiole index (LPI) and petiole width (DPW) had high loading values, which could comprehensively reflect the other 14 variables. The scatter plot of the principal components could clearly distinguish 19 species of this genus. The results of cluster analysis showed that the 19 species of the genus Aphaenogaster could cluster into four branches. The first branch is closest to the second branch and the farthest from the fourth. The results were basically consistent with the clustering situation of the scatter diagram of principal components and the classification results of morphological characteristics. Conclusion The research method of morphometry has a good application in the taxonomic study of Formicidae, and has an important application prospect, which can provide a new method for species classification and identification.
, Available online , doi: 10.12403/j.1001-1498.20230081
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Objective To understand the species and the distribution of parasitoids in the galls of the cynipid wasps on Quercus variabilis in China, an investigation was conducted from 2019 to 2022. The results will lay a foundation for biological control of cynipid wasps. Method The cynipid wasp galls on Q. variabilis were collected through field investigation. The parasitoids in the galls were reared under laboratory conditions, and the specimens were both examined and identified. Result A total of 26 species of parasitoids belonging to 9 families, 17 genera, with 5 new records in China, were identified in the galls from 12 species of cynipid wasps on Q. variabilis in China. Their distribution was introduced. Conclusion This study reports 26 parasitoids species in the galls of cynipid wasps on Q. variabilis, and summarizes their corresponding gall morphology and distribution. In addition, color photographs of galls and parasitoids are acquired.
, Available online , doi: 10.12403/j.1001-1498.20230037
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Objective Agrothereutes minousubae Nakanishi (Hymenoptera: Ichneumonidae) is a specific ectoparasitoid which attacks the prepupae and pupae of Pryeria sinica Moore (Lepidoptera: Zygaenidae), an important insect pest of garden plants, causing high mortality of the host species. To make use of this potential biological control agent, it’s critical to study the ontogeny and reproductive characteristics of A. minousubae. Method The ontogeny, reproductive system and reproductive behavior of A. minousubae, which was a new record species in Henan Province, were systematically determined using field collection and indoor rearing at 24 ± 1 ℃. Result It took 48 to 50 hours for the wasp to complete embryonic development. The larvae have 4 instars. The prepupa and pupa stages undergo drastic morphological changes and pigment deposition. The adults had obvious sexual dimorphism, and one generation lasts for 23 to 27 days. A female usually has 9～11 polytrophic ovarioles. There was a pair of testes with long and thin vas deferens in male internal reproductive system. Male wasps exhibited wing fanning and antennal drumming during courtship behavior when exposed to females. Males played a dominant role in mating behavior. Males copulated more than one time while female usually copulated only once in their life time. A female deposited 7 eggs daily, deposited about 20 eggs in its lifetime, and had superparasitism behavior. Conclusion A. minousubae is a synovigenic ectoparasitoid with relatively large egg and strong parasitic ability. This parasitoid has great value of protection and utilization. The study can provide the basis for better protection and utilization of this wasp against P. sinica.
, Available online , doi: 10.12403/j.1001-1498.20230077
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Objective To study the effects of the histone deacetylase inhibitor Trichostatin A (TSA) on the physiological characteristics of leaf morphology, photosynthetic indexes, proline, malondialdehyde and abscisic acid content, synthetic histone deacetylase, abscisic acid and flavonoid-related genes of sea buckthorn cuttings under the conditions of simulated drought and post-drought rehydration of 20% polyethylene glycol. Methods The drought-related physiological indexes of sea buckthorn cuttings were measured, and the gene expression was detected by quantitative real-time PCR. Result TSA-pretreated (1 μmol·L−1) sea buckthorn was enhanced in drought tolerance under equal drought stress. (1) Compared with the drought treatment, the degree of leaf sagging and wilting reduced, the degree of fresh weight decline was smaller, and the degree of plant recovery after rehydration was greater. (2) The net photosynthetic rate, transpiration rate, stomatal conductivity, PSII maximum photochemical efficiency Fv/Fm value, PSII effective photochemical quantum yield Y(II) value and chlorophyll relative content (SPAD) value all significantly increased, and all were adjusted down after rehydration. (3) The content of proline and flavonoids increased significantly, the content of malondialdehyde and abscisic acid decreased significantly, and the trend was the same after rehydration. (4) The expression of histone deacetylase genes HrHDA6 and HrHDA19, abscisic acid synthesis-related genes ABF1 and NAC2 were significantly down-regulated, and the expression of flavonoid synthesis-related genes C4H2 and CHS4 were significantly upregulated, and the trend after rehydration was the same. Conclusion TSA can improve the drought resistance of sea buckthorn by regulating the physiological and gene expression of sea buckthorn cuttings in response to drought stress, and this study lays an important foundation for in-depth analysis of the regulatory mechanism of histone acetylation affecting sea buckthorn drought resistance.
, Available online , doi: 10.12403/j.1001-1498.20220608
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Objective To reveal the sequence characteristics and expression profiles of CD36 homolog genes, sensory neuron membrane proteins (SNMPs) and class b scavenger receptors (SRb) in Orthosia songi Chen et Zhang. Method Specific primers were used to clone the SNMP and SRb genes. The protein encoded by these genes were constructed by homo-modeling, and the gene expression profiles were determined by quantitative fluorescent real-time PCR. Result Three CD36 homolog genes (OsonSNMP1, OsonSNMP2 and OsonSRb1) were identified from O. songi. The proteins encoded by these genes consisted of two transmembrane domains and an extracellular domain. The extracellular domain contained an antiparallel β-barrel core and a hydrophobic domain near the top. OsonSNMP1 was mainly expressed in the antennae and wings of male and female moth, and the expression level in male antennae was significantly higher than that in other tissues. OsonSNMP2 was discriminatorily expressed in male and female antennae and female wings, and its expression level in female antennae was significantly higher than that in other tissues. OsonSRb1 were specifically expressed in the antennae and mouthparts of male and female. Conclusion The proteins encoded by OsonSNMP1, OsonSNMP2 and OsonSRb1 have similar structures with CD36 receptors in vertebrates. Their expression profiles highly associated with olfactory organs indicate the potential roles in olfactory systems. These results provide experimental data for further study on the olfactory function of CD36 homolog genes in Orthosia songi.
, Available online , doi: 10.12403/j.1001-1498.20220560
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Objective Acid-aluminum stress is an important abiotic stress factor limiting plant growth, which seriously restricts the productivity of acid soil forests in southern China. In order to explore the growth variation law under acid aluminum environment of Pinus massoniana seedlings, sselect aluminum-tolerant families and sensitive families adapted to aluminum stress, and provide basis for genetic improvement of Pinus massoniana under aluminum stress. Method The seedlings of 55 second-generation superior families (201 - 255) were used to study the growth and root morphological changes under 0, 0.1, 0.3, 0.6, 1.2 and 2.4 mmol·L−1 aluminum concentration in acidic environment by sand culture of P. massoniana. The aluminum tolerance characteristics were graded by principal component analysis and cluster analysis. The excellent aluminum tolerance, the superior families of the seedlings were sselected and identified. Results There were significant differences in seedling height, ground diameter, height-diameter ratio, biomass (aboveground biomass, root biomass, total biomass, root-shoot ratio), root morphology (total root length, root surface area, root volume) between families and aluminum concentration treatments (p <0.05). The ground diameter, seedling height, biomass and root morphological indexes increased first and then decreased with the increase of aluminum concentration of the seedlings, which was the highest at 0.6 mmol·L−1 aluminum concentration, significantly higher than that of 0 and 2.4 mmol·L−1 treatment. There were no significant differences with 0.3 mmol·L−1 treatment. The coefficient of variation of root biomass and root morphology was large, with an average of 30.79%. Using the above 10 indicators to calculate the comprehensive evaluation value (CEV) and analyze for systematic clustering of aluminum resistance characteristics among families, 3 families with strong aluminum resistance (accounting for 5.45%) and 11 families with moderate aluminum resistance (accounting for 20%) were selected. 37 families (67.28%) with general aluminum tolerance, and 4 families (7.27%) with aluminum sensitivity were evaluated. Conclusion Suitable aluminum concentration can promote the growth, especially at the concentration of 0.3-0.6 mmol·L−1 aluminum. Selecting aluminum-tolerant and sensitive families is of great significance for the improvement of aluminum tolerance of P. massoniana.
, Available online , doi: 10.12403/j.1001-1498.20230164
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Objective To investigate the changes in the content of four endogenous hormones in the embryo and endosperm during the development process of Osmanthus fragrans ‘Zigengziyin’ seeds, and to explore the patterns of endogenous hormone changes during this process. Method Osmanthus fragrans ‘Zigengziyin’ seeds were used to measure the contents of endogenous hormones auxin (IAA), gibberellin (GA), zeatin nucleoside (ZR) and abscisic acid (ABA) in embryo and endosperm during different periods in seed development. Result During the development of seeds, GA3 contents in embryo decreased, but the ABA contents in embryo increased. IAA and ZR contents in embryo increased firstly then decreased and increased finally. The Ratio of GA3/ABA also decreased continuously. Both the ratios of IAA/ABA and ZR/ABA decreased firstly then increased. The change in GA3/ABA in the embryo was greater than ythe change in the ratios of IAA/ABA and ZR/ABA. The content of GA3, IAA, and ZR in the endosperm increased during the development, while the content of ABA first decreased, then increased, and remained stable. The ratios of GA3/ABA, IAA/ABA, and ZR/ABA decreased, and the variation amplitude of GA3/ABA ratio in endosperm was greater than that of IAA/ABA and ZR/ABA. Conclusion The dynamic changes in the content of four endogenous hormones in the embryo and endosperm during the seed development process of O. fragrans ‘Zigengziyin’exhibite a certain regularity. The ratio of GA3/ABAin embryo and endosperm both decrease, and the changes are greater than of the changes in IAA/ABA and ZR/ABA. The ratio of GA3/ABA may be the key factor affecting seed development.
, Available online , doi: 10.12403/j.1001-1498.20230083
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Objective To study the genomic selection of poplar growth traits and complete early selection. Method The female parent Populus deltoides ‘Danhong’, the male parent Populus simonii ‘Tongliao 1’, and 362 F1 generations were used to determine the growth traits (ground diameter, plant height, and stem biomass) under treatments with fertilization and no fertilization in the field. Three genome-wide selection models, gBLUP, sBLUP, cBLUP, and phenotypic observations of 364 clones were used to predict breeding values for 502 genotypes. Results The stem biomass of ‘Danhong’ increased by 20 times and 32 times compared to ‘Tongliao 1’ under high- and low-nitrogen conditions, respectively. The accuracy of gBLUP prediction for growth traits was close to 1, the accuracy of sBLUP prediction ranged from 0.5 to 0.8, and the accuracy of cBLUP prediction was less than 0.2. The results showed that the gBLUP model predicted the best and the cBLUP predicted the worst. The hybrid population based on yhe breeding values of stem biomass calculated from the gBLUP model could be classified into four types: double high-efficiency type, double low-efficiency type, low nitrogen high-efficiency type, and high nitrogen high-efficiency type. The excellent clones 16-1-16, 16-1-194, 13 - 116,13 - 73, 13-481, 13-268, 13-286, 13-566, 13-173, 13-578, 16-1-65, 13-242, 16-1-189, 13-40, 13-608, 16-1-170, 16-1-22, 13-237, 13-272, and 13-335 were identified. Conclusion There are significant differences in growth phenotypic traits between ‘Danhong’ and ‘Tongliao 1’. The results help us complete the early selection of poplar breeding work, reduce the cost of phenotype determination, and improve breeding efficiency.
, Available online , doi: 10.12403/j.1001-1498.20220501
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Objective To reveal the variation of potential evapotranspiration and crop coefficient of Vitex negundo L. var. heterophylla (Franch.) Rehd., for providing a basis for water resources management and vegetation construction of semiarid area. Method Based on the lysimeter data, daily meteorological data, leaf area index (LAI) data and growth of new shoot length data from May to October in the year of 2021 in Henan Yellow River Xiaolangdi Earth Key Belt National Field Science Observatory, combined with the Penman-Monteith formula, the trends of potential evapotranspiration (ET0)and crop coefficient of Vitex negundo L. var. heterophylla (Franch.) Rehd. under abundant water conditions in different growth stages and their relationship with physiological growth indexes were analyzed. Result (1) During the growth stage of Vitex negundo L. var. heterophylla (Franch.) Rehd., the ET0 value showed a downward trend. The ET0 value was higher in May and June, and began to decline after July. The total value of ET0 was 630.86 mm, and the daily average value was 3.43 mm·d−1. (2) The potential evapotranspiration during the growth period of Vitex negundo L. var. heterophylla (Franch.) Rehd. showed a parabolic trend. The potential evapotranspiration was the largest at blossom stage, with total value of 336.26 ± 18.19 mm and daily average value of 5.51 ± 0.30 mm·d−1, followed by fruiting stage and leaf unfolding stage, and the lowest value was found at defoliation stage with a total value of 41.57 ± 3.61 mm and a daily average value of 1.98 ± 0.17 mm·d−1, respectively. The total value of potential evapotranspiration during growth stage of Vitex negundo L. var. heterophylla (Franch.) Rehd. was 716.47 ± 40.21 mm, with a daily average value of 3.89 ± 0.22 mm·d−1. (3) LAI and new shoot length increased rapidly in May and June, and then the growth rate slowed down gradually. The maximum value of LAI reached its maximum value (2.93 ± 0.07) in August, then began to decline, and the minimum value was found in October, with the value of 1.63 ± 0.08. The growth of new shoots was the largest in May, 6.85 ± 0.25 cm, and basically stopped growing in October. (4) During the growth stage, the crop coefficient showed a parabolic trend, with the largest fruiting period (1.45 ± 0.22), followed by flowering period (1.25 ± 0.13), leaf spreading period (0.98 ± 0.05) and leaf falling period ( 0.95 ± 0.14) was the smallest, and the average of the whole growth period was 1.28 ± 0.16. There was a significant positive correlation between crop coefficient and LAI (p < 0.01), with the coefficient of determination R2 0.736, and there was no significant correlation between crop coefficient and growth of new shoot length (p > 0.05).
, Available online , doi: 10.12403/j.1001-1498.20220604
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Objective This study amid to analyze the role of PeERF1 gene under drought stress in Populus euphratica, and evaluate the physiological adaptation mechanism of PeERF1 transgenic ‘ 84k’ (Populus alba × Populus glandulosa ‘84k’) to drought resistance for providing insights into further study of the drought resistance regulation mechanism of this gene in woody plants. Methods The drought (0, 12 and 24 h) treatment simulated with 20% PEG6000 was carried out on P. euphratica to analyze the temporal and spatial expression pattern of the PeERF1. Based on non-transgenic (WT), overexpressing 35S::PeERF1 transgenic plants (PE), and dominantly suppressed 35S::PeERF1-SRDX transgenic plants (SE), WT, PE and SE were treated with different concentrations of PEG-6000 (Control and 20%) to simulate drought stress, and analyzed for growth traits and physiological indicators. Results The results showed that the expression level of PeERF1 gene was the highest in leaves of P. euphratica, followed by stems and roots. Under drought stress treatment, the transgenic plants showed little change in growth traits, chlorophyll content, catalase (CAT), malondialdehyde (MDA) and peroxide dismutase (POD) content between the transgenic plants and the WT under normal conditions. Under 20% PEG6000 treatment, the PE transgenic plants showed better growth status, and higher chlorophyll content, CAT and POD content than WT, and the PE transgenic plants showed lower MDA content than WT, while the SE transgenic plants showed opposite traits. Conclusion Under drought dress, significant changes are found in the growth status, chlorophyll content, catalase, malondialdehyde and peroxidase related physiological indicators of transgenic plants. PeERF1 plays a positive regulatory role on transgenic P. alba × P. glandulosa ‘84k’ in response to drought.
, Available online , doi: 10.12403/j.1001-1498.20220543
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Objective To study the effect of biological carbon on soil iron reduction in Chinese fir plantations under the condition of abundant rainfall and long-term soil water saturation, and analyze the community structure changes of iron-reducing bacteria and phosphorus solving bacteria in soil, for clarifying the influence of biochar on soil iron reduction and its relationship with phosphorus form transformation. Method Based on the red soil of Chinese fir plantations, Chinese fir leaves under the forest were collected and fired to produce 300℃ and 500℃ biochar. Biochar was added at 0, 1% and 3% for 40 days of indoor culture.The basic chemical nutrients of soil were analyzed. The content of different phosphorus forms in soil was determined by the modified Hedley method, and the community structure of soil phosphate solubilizing bacteria and iron reducing bacteria was analyzed by high-throughput sequencing technology. Result The content of soil active phosphorus increased with the increase of the amount of biochar, and most of them were the H2O-Po and NaHCO3-Pi. The content of Residual-P decreased with the increase of biological carbon. The copy number of genes of Fe (III)-reducing bacteria in flooded treatment group was higher than that in non-flooded treatment group, and increased with the increase of biochar firing temperature under the same water condition. The content of ferrous ions in flooded treatment group was much higher than that in non-flooded treatment group, and decreased with the increase of biochar addition. The soil chemical properties such as pH, TC and TP contents in the flooded group were higher than those in the non-flooded treatment group, and increased with the increase of biochar addition amount. The richness of soil phosphorus solubilizing bacteria community increased with increasing firing temperature, and the community structure and diversity of phosphorus solubilizing bacteria also increased with increasing firing temperature. Conclusion The anaerobic conditions promote the reduction of Fe (III). The addition of biochar changes the chemical properties of soil, affects the community structure and diversity of phosphorus solving bacteria and the growth microenvironment of iron reducing bacteria. Under the double action of microorganism and Fe (III) reduction, the conversion of residual phosphorus and sodium hydroxide phosphorus into aqueous phosphorus and sodium bicarbonate phosphorus are promoted, and the availability of soil phosphorus is enhanced. Therefore, in the southern regions with abundant rainfall, the application of biological carbon in Chinese fir plantation can improve the soil nutrient status and provide enough phosphorus for the growth of Chinese fir.
, Available online , doi: 10.12403/j.1001-1498.20230134
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Objective To study the characteristics of understory plant communities of plantations and their relationship with stand factors, which is of great significance for evaluating the effectiveness of vegetation restoration in sandy areas and managing plantations. Methods In this study, based on the poplar plantation in Mu Us sandy land the understory plant community was investigated. The effects of stand factors such as canopy density and density on understory vegetation were studied. Results The results showed that a total of 32 species of herbaceous plants belonging to 28 genera of 12 families were found in the herbaceous layer under the poplar plantation in the study area,. Among them, Leguminosae, Gramineae and Compositae plants were the most species, accounting for 62.51% of the total plant species. The life forms of understory herbaceous plants were mainly perennial herbaceous plants, accounting for 78.13% of the total species. The plant water ecotypes were mainly xerophytes and mesoxerophytes, accounting for 75.00% of the total species, followed by xeromesophytes and mesophytes. The Margalef richness index, Simpson dominance index, Shannon-Wiener diversity index and Pielou evenness index of understory herb layer ranged from 1.20 to 3.17, 0.48 to 0.88, 0.95 to 2.34 and 0.16 to 0.48, respectively. The species diversity was the highest when the forest age was 32 years. The results of the structural equation model showed that canopy density and stand density were negatively correlated with the coverage of the understory shrub layer. When the plantation canopy density was high, no shrub layer was found under the forest. The increase of canopy density was beneficial to the development of herbaceous layer, and there was a negative effect relationship between stand density and herbaceous layer, which affects the growth of herbaceous plants under the forest. The effect of shrub layer on herbaceous layer was similar to that of tree layer. Conclusion The diversity of understory herbaceous plants in poplar plantations in Mu Us Sandy Land is high, and there are fewer shrub species. The size is obviously affected by stand factors such as canopy density and stand density. Appropriate regulation of stand density and structure will be conducive to the maintenance of understory species diversity and close-to-nature management of poplar plantations in Mu Us Sandy Land.
, Available online , doi: 10.12403/j.1001-1498.20230050
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Objective Based on the REF6 and BRR2a genes, this study aimed to explore the distribution of the genetic diversity, the route of migration and the relationship between population genetic variation and environmental change of different populations of Populus davidiana. Method After obtaining the CDS sequences of REF6 and BRR2a genes, we calculated the molecular diversity index, constructed the haplotype network maps and the phylogenetic trees of the different CDS sequences. Result In the southwestern population, the mean of the three neutral tests for the REF6 and the BRR2a gene were negative, and the nucleotide polymorphisms were lower than those in both the northern and central populations. The result of phylogenetic tree and haplotype network maps showed that the outgroup first clustered with the northern population of P. davidiana. The southwest population tended to gather at the end, and the haplotypes of the two genes were abundant in the north and the central population. The haplotypes in the southwestern population were relatively single. Conclusion P. davidiana migrates from the north to the south. In order to adapt to the climate of Yunnan-Guizhou Plateau, population located in the southwest region experiences strong natural selection, and local adaptation occurs in the southwest populations.
, Available online , doi: 10.12403/j.1001-1498.20230069
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Objective : This study aimed to evaluate the drought resistance of two histidine kinase PagHK3a gene knockout lines of poplar '84k' (Populus alba × P. glandulosa '84k'), and explore the molecular regulatory mechanism of PagHK3a gene in poplar response to drought stress. Method : Plantlets of wild-type (WT) and gene knockout strains (C1 and C2) sub-cultured for 25 days were treated with 5% PEG and the mature leaves of the plantlets were gathered 3 hours later. Quantitative real-time PCR (qPCR) was used to detect the expression levels of PagHK3a gene, PagHK3a downstream related genes, drought stress response genes and antioxidant related genes in leaves of the three lines. Meanwhile, the drought stress treatment was carried out using the potted plants of each line by weighing method with three levels: normal watering greenhouse (soil relative water content: 70%-75%), moderate drought (40%-45%) and severe drought (25%-30%). After four weeks of drought stress treatment, transient photosynthetic parameters, contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA), activities of peroxidase (POD) and superoxide dismutase (SOD), plant height and ground diameter of WT and C1, C2 were measured. Result : Under moderate drought conditions, the height growth of both C1 and C2 lines was significantly higher than that of WT, but under severe drought conditions, the height growth of both lines was not significantly different from that of WT. Analysis of photosynthetic parameters revealed that the stomatal conductance and intercellular carbon dioxide concentration of C1 and C2 were significantly higher than those of WT under moderate drought condition, but only C2 was significantly higher than that of WT under severe drought stress condition. Under moderate drought stress, the instantaneous net photosynthetic rate of C1 was significantly higher than that of WT, and under severe drought stress, the instantaneous net photosynthetic rate of C2 was significantly higher than that of WT. At the same time, the results of biochemical indexes showed that MDA and H2O2 contents in knockout lines C1 and C2 were significantly lower than those in WT under moderate drought stress, but only C2 was significantly lower than that in WT under severe drought stress. Comparative analysis of the antioxidant enzyme activity of each line found that, under normal water supply conditions, the POD enzyme activity of C1 strain and the SOD activity of C2 strain were significantly higher than that of WT. And under moderate drought stress, the two protective enzyme activities of C1 strain were significantly higher than that of the control, while C2 was significantly higher than that of WT only under severe drought stress. In addition, under 5% PEG treatment, the expression levels of histidine kinase gene PagHK3a and its downstream response regulatory proteins PagRR2 and PagRR15 in the leaves of gene knockout lines C1 and C2 were significantly down-regulated compared with those of WT. The expression levels of drought stress response gene PagNAC3 and peroxidase synthesis gene POD1 were significantly up-regulated, while the expression level of superoxide dismutase synthesis gene SOD4 was not significantly different from that of WT. Conclusion : In PagHK3a knockout lines, expression of PagHK3a was down-regulated, expression of its downstream genes PagRR2 and PagRR15 in the cytokinin signaling pathway was also significant down regulated and the expression of stress response gene PagNAC3 and POD synthesis gene POD1 were significantly up regulated; meanwhile the PagHK3a knockout lines had stronger gas exchange ability, lower MDA and H2O2 content and larger plant height growth under moderate drought conditions, therefore had stronger drought stress resistance than WT.
, Available online , doi: 10.12403/j.1001-1498.20230147
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Objective To analyze the effects of thinning and interplanting measures on the growth traits, spatial use capacity and stand yield for providing a scientific basis for managing Chinese fir plantation. Method The response of Cunninghamia lanceolata stand quality to thinning and interplanting was explored by comparing the pure forest of control treatment (CK: thinning intensity 0%, 1 740 trees left per hectare) with thinned forests (Ⅰ: 47%; Ⅱ: 56%; Ⅲ: 65%) and replanted Phoebe chekiangensis and Sassafras tzumu , and the improvement effect of thinning and interplanting on the growth of Chinese fir was comprehensively evaluated by principal component analysis. Result (1) Thinning and broadleaf trees interplanting promoted tree growth of Chinese fir. Forest had the highest DBH, tree height, individual tree volume, and timber yield under treatment III, which increased by 32.07%, 21.60%, 83.33%, and 6.77% respectively compared to CK (P<0.05) . However, the height-diameter ratio, breast-height form factor, the yield of small strips, small diameter wood, fuelwood and waste wood were lower than CK, with a decrease of 8.64%, 3.70%, 90.88%, 41.47%, 54.50% and 5.71% respectively compared with CK. (2) The space use capacity of Chinese fir plantations changed significantly after thinning and broadleaf trees interplanting. The crown width, crown length, crown ratio, crown shape, canopy surface and canopy volume were all significantly higher than those of CK, with the growth rates of 12.16%～31.00%, 55.58%～61.24%, 30.00%～40.00%, 16.11%～44.94%, 67.17%～95.86%, 84.74%～146.63%. (3) The thinning and interplanting treatments can effectively improve the growth of Chinese fir. The comprehensive score in treatment III (1.186) was the highest, followed by II (1.092), I (0.671), and CK (-0.709). Conclusion If the Chinese fir plantation management is to rapidly improve the growth, treatment III (65% thinning and interplanting broadleaf trees) is the best measure.
, Available online , doi: 10.12403/j.1001-1498.20230214
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Objective To explore the characteristics of soil bacterial community diversity and structure with the treatment ofconversion of coniferous into broadleaved plantations. Method The bacterial 16S rRNA gene high-throughput sequencing was performed on samples of the coniferous Pinus massoniana Lamb plantation (PMP) as well as native broadleaved Castanopsis hystrix Miq. plantation (CHP), Mytilaria laosensis Lec. plantation (MLP) and Michelia macclurei Dandy plantation (MMP) in the southern subtropical China collected from the topsoil (0-20 cm)、middle layer(20-40 cm) and subsoil (40-60 cm) under each stand in February 2017. The diversity and structure of soil bacterial community taxonomy and phylogeny after conversion from PMP to native broadleaved plantations were studied. Results The results showed that: (1) The taxonomic and phylogenetic diversity of bacterial communities in topsoil increased significantly after conversion from PMP to MLP and MMP, which mainly caused by the soil water content (SWC). (2) After CHP, MLP and MMP replaced PMP, the taxonomic structure of topsoil bacterial community changed markedly, and only CHP changed significantly in the middle layer, which were limited by soil SWC, total phosphorus (TP), total nitrogen (TN) and carbon-nitrogen ratio (C/N). (3) After the transformation from PMP to native broadleaved plantations, the phylogenetic structure of bacterial community remains clustered in vas soil layers, and environmental filtration was still the main factor regulating community assembly. (4) In the topsoil and middle layer, the taxonomic and phylogenetic turnover rates from PMP to CHP were higher than that from PMP to MLP or MMP, indicating that stability of the soil bacterial community in the CHP stand was poor. Conclusion Overall, considering the diversity and turnover rates of soil bacterial community taxonomy and phylogeny, the stability of the soil bacterial community after converting PMP into MLP or MMP is higher than that after converting to CHP.
, Available online , doi: 10.12403/j.1001-1498.20230126
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Objective On the basis of the optimum mycelial growth temperature investigation of Coryneum populinum Bres, the pathogen was measured for susceptibility to five fungicides. The approach provides a theoretical reference for disease control of poplar gray spot and fungicide acting mechanism against the pathogen. Method The mycelium growth rate method and conidia germination method were used to determine the antibacterial effects of five tested fungicides on C. populinum mycelium growth and conidia germination, and the toxicity regression equation was constructed and the EC50 value was calculated. The morphological changes of mycelia and conidial germination were observed after fungicide treatment. Result The optimum mycelial growing temperature of C. populinum was 20 ℃ with the colony diameter of 4.25cm after 25 days, and the conidial germination rate was 79.00% after 12h on PDA. The mycelial growth and conidial germination were both inhibited at above 30 ℃. The inhibitory effects of the five fungicides on mycelial growth of the pathogen showed the trend of Difenoconazole > Tebuconazole > Carbendazim > Prochloraz > Thiophanate-methyl, with the average EC50 values of 0.0048, 0.024, 0.047, 0.25 and 0.49μg·mL−1, respectively. The virulence of the five fungicides to the pathogen’s conidial germination showed the pattern of Difenoconazole > Prochloraz > Thiophanate-methyl > Carbendazim > Tebuconazole, with the average EC50 values of 85.07, 101.23, 123.28, 254.80 and 327.78μg·mL−1, respectively. The hyphal surface of the pathogen became rough with enlarged branches, and no spore was produced after application of Difenoconazole. The conidial germination became morphologically abnormal with branching and enlargement or no enlagement of germ tubes. Conclusion The fungicide difenoconazole has high virulence to C. populinum, and it shows a potentially effective candidate agent for management of popular grey spot.
, Available online , doi: 10.12403/j.1001-1498.20230024
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Objective To clarify the variation patterns of fruit traits in hybrid offspring of Castanea henryi, and to conduct comprehensive evaluation and selection of excellent individual plants. Method The genetic diversity and variation of 7 shape feature traits and 12 quantitative traits of the fruit phenotype of 143 individual plants of F1 generation of Castanea henryi were analyzed, and all individual plants were comprehensively evaluated by principal component analysis and grey correlation analysis. Result The results showed that the diversity index of 6 shape feature traits such as nut shape in F1 hybrid generation was greater than 0.8, which showed high genetic diversity. Among the 12 quantitative characters, fruit bract mass, total nut weight and single nut weight had a large variation range, and the smallest variation range was the percentage of kernels. The differences of fruit phenotypic characters among single plants were very significant (P < 0.01), which had great selection potential. There were 42 groups of extremely significant correlation (P < 0.01) and 6 groups of significant correlation (P < 0.05) among the 12 fruit quantitative traits, and joint selection could be carried out. The highest comprehensive score of single plant was G-98 through principal component analysis and grey correlation analysis, and 10 excellent single plants including G-98 were selected by these two methods. Conclusion There are rich variations and correlations among various phenotypic traits in the F1 hybrid of Castanea henryi, and the overlap of comprehensive selection results is high. The results lay a foundation for the creation of new germplasm and the breeding of fine new varieties of Castanea henryi.
, Available online , doi: 10.12403/j.1001-1498.20230194
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Objective To investigate the changes of soil microbial community along the altitude gradient in the natural stand of Castanopsis fargesii and their correlation with soil physicochemical properties in the Guoyan Mountain for revealing the impact of climate change on soil microbial diversity and community composition and the influencing factors of Castanopsis fargesii under the small-scale elevational gradients in the subtropical region of China. Methods The topsoils of the natural stand of Castanopsis fargesii along an elevation gradient in the Guoyan Mountain Nature Reserve were selected and their physicochemical properties were determined, and Illumina high-throughput sequencing was performed. The correlation analysis and redundancy analysis were used to study the characteristics of soil microbial diversity and community composition and their influencing factors. Results The alpha diversity of soil bacteria did not show a clear elevational pattern, while the alpha diversity of fungi first decreased and then increased along the elevation gradient, which was different from the studies across large-scale elevational gradients. The dominant bacterial phyla were Acidobacteria, Actinobacteria and Proteobacteria; the dominant bacterial genera were norank_f_norank_o_subgroup_2 and norank_f_xanthobacteraceae; the dominant fungal phyla were Basidiomycota and Ascomycota; the dominant fungal genera were Russula and Lactifluus. Our results showed that small-scale elevational gradients did not significantly affect the changes in the dominant microbial phyla and genera. The relative abundance and community composition of the dominant bacterial phyla and genera were closely related to soil pH, total phosphorous and available nitrogen, while soil total phosphorus and available potassium were the most important factors affecting the composition of fungal communities. Soil properties could well predict the changes in soil microbial communities, even on small scale elevational gradients. Conclusion Soil properties and altitude both influence the ecogeographic distribution of soil microorganisms in the Guoyan Mountain Nature Reserve. This study will provide a scientific basis for the study of soil microbial diversity and community composition conservation along small-scale elevation gradients in southern subtropical broad-leaved evergreen forests.
, Available online , doi: 10.12403/j.1001-1498.20230061
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Objective To understand the influence of various factors on the rooting rate of Eucalyptus urophylla × E. grandis, by using different types of culture media and different concentrations of hormones treated with four E. urophylla × E. grandis clones and to provide the theoretical support for the rapid propagation and cultivation of E.urophylla × E. grandis. Method In this study, based on the four clones (EC262, EC264, EC269 and EC272) of E.urophylla × E. grandis from the same parents but with different rooting , the experiment with 4 factors and 4 levels having total 16 treatments was designed. Rooting rate, rooting number, average root length, longest root length were investigated on 30 days. the rooting traits were evaluated and the rooting effect of each treatment combination was analyzed using the range analysis method. Results The type and concentration of plant growth regulators, the type of culture medium and the clones all had a significant impact on the rooting effect. The four clones were all able to take root under different treatments. The rooting rates ranged from 7.5% to 55%; average number of roots ranged from 1 to 3.27; average root length ranged from 1.95 to 5.02 cm; average root length ranged from 2.18 to 7.03 cm; and the rooting traits score ranged from 27.78 to 75.75%. In addition, range analysis showed that the root rate and root number, representing the root generation ability in the early rooting stage, were mainly affected by clones, while the average root length, the longest root length and the evaluation of rooting traits representing the quality of the subsequent root system, the role of the medium More than the clones played a more important role. Conclusion In the initial stage of rooting of the four clones of Eucalyptus urophylla × E. grandis, genetic factors are the dominant factor in the rooting differences, while in the subsequent stages of root development, environmental factors have a greater influence than genetic factors. The results of this study can provide theoretical support and technical reference for the optimization of the tissue culture propagation technology system of Eucalyptus and other trees.
, Available online , doi: 10.12403/j.1001-1498.20230163
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Objective To analyze the genetic diversity of the Cunninghamia lanceolata germplasms from Jiangxi Province, the molecular ID of the germplasms was studied for providing theoretical basis and core materials for further research and utilization of the germplasms. Method The genetic diversity of the germplasms was analyzed by SSR markers. A core collection was constructed through the allele number maximization strategy (M strategy). The core collection of the germplasms was assessed by the genetic diversity parameters and their retention ratio. The the core collection was confirmed with t-test and PCoA analysis. Based on the principle of distinguishing the most varieties using the fewest marker, the more effective SSR markers were selected to construct the molecular fingerprints and IDs of core germplasms. Result A total of 122 alleles were detected in the 495 germplasms by 20 SSR markers. The means of Shannon's information index (I), Nei's genetic diversity index (H), observed heterozygosity (Ho), and expected heterozygosity (He) were 0.762, 0.400, 0.394, and 0.400, respectively, which indicated a relatively high genetic diversity of the germplasms. The core collection of the 52 germplasms was constructed by M strategy in Core finder software. 10.5% of the core collection retained 100.0% of the original collection of Na. The retaining ratio of the Na, Ne, I, H, Ho, He and PIC was 100.0%, 107.4%, 115.1%, 109.0%, 104.1%, 110.0% and 111.2%. The t-test analysis suggested that there were no significant differences between the core collection and original collection. This result was further confirmed by the PCoA analysis. Combining with the 4 SSR markers, H97 and H286, CLSSR9 and CLSSR37, the 52 core collections could be identified. And the molecular fingerprints and IDs of core collections were constructed. The molecular IDs were illustrated as barcodes and QR codes. Conclusion There is relatively abundant genetic diversity of C. lanceolata germplasms in Jiangxi. The 52 core collections are representative. The 4 more effective SSR markers mentioned above can identify the 52 core collections of Chinese fir from Jiangxi and can be successfully used for establishing molecular ID codes.
, Available online , doi: 10.12403/j.1001-1498.20230133
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Objective In order to improve the productivity and timber quality of Chinese fir (Cunninghamia lanceolata), a pruning experiment was carried out in a Chinese fir plantation. The impacts of pruning intensity on stem growth and knot free timber production were analyzed, which aims to provide guidance for cultivation of knot free timber. Method In this study, we performed different pruning intensities in 8-year-old Chinese fir plantation, including light intensity pruning (retaining 75% of crown height, LP), heavy intensity pruning (retaining 50% of crown height, HP) and the control (unpruned, CK). The quantity and size of knots were measured by rotary cutting method. The differences of DBH, height, volume and the quantity or size of knot among different treatments were compared after 10 years of pruning. Results Results showed that pruning had no significant effect on DBH, tree height, volume, plumpness, height of the first living branch and quantity of living branches of Chinese fir. Pruning substantially decreased the quantity of knot of self-pruning, so the diameter, length and volume of knot after pruning were lower than self-pruning knots. LP and HP remarkably reduced total diameter of knot per tree by 27.6% and 40.8%, and total length of knot per tree by 26.4% and 32.6%, and total volume of knot per tree by 27.8% and 45.0%, respectively. Moreover, compared with the knotted wood, the density of knot free timber was significantly decreased, and the compressive strength and bending strength were increased significantly. Conclusion It is appropriate to take pruning measures in Chinese fir silviculture plantations, which can not only effectively reduce quantity and volume of knot, and improve the appearance grade and knot free timber , but also maintain the tree growth and stand volume.
, Available online , doi: 10.12403/j.1001-1498.20220565
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Geographical variation of tree species population is the basis of tree selection and breeding. It is of great significance to study the climate sensitivity of radial growth of different provenances for seed allocation and selection of superior provenances. This paper reviews the long-term and short-term responses of radial growth of different provenances to climate change, suggesting that the response characteristics to climate change vary among different provenances. The response of radial growth of different provenances to climate change can be used to guide provenance selection in the future climate. However, there is still a lack of research on the response of different provenances to climate change, and the response of provenance growth to climate change needs to be further studied. Using the method of dendroclimatology to explore the response of radial growth of different provenances to climate change can effectively promote forest cultivation management and guide the selection of productive and adaptable seed sources for reforestation.
Geographical variation of tree species population is the basis of tree selection and breeding. It is of great significance to study the climate sensitivity of radial growth of different provenances for seed allocation and selection of superior provenances. This paper reviews the long-term and short-term responses of radial growth of different provenances to climate change, suggesting that the response characteristics to climate change vary among different provenances. The response of radial growth of different provenances to climate change can be used to guide provenance selection in the future climate. However, there is still a lack of research on the response of different provenances to climate change, and the response of provenance growth to climate change needs to be further studied. Using the method of dendroclimatology to explore the response of radial growth of different provenances to climate change can effectively promote forest cultivation management and guide the selection of productive and adaptable seed sources for reforestation.
, Available online , doi: 10.12403/j.1001-1498.20220545
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Objective Water is an important factor limiting the growth and survival of plants in arid areas. The effects of precipitation changes on the desert Phytochemistry metrological characteristics, and the distribution of C, N, P and K elements in various plant organs are explored. Method Based on the second-class of rare-endangered plants in China, Ammopiptanthus mongolicus, the only evergreen broad-leaved shrub in desert area, this paper analyzed the ecological stoichiometric characteristics of roots, stems and leaves of A. mongolicus under different precipitation gradients. Results The results showed that the C content in the leaves was the most, followed by stems and roots, the nutrient contents of N、P and K in the leaves were also the most, followed by the roots and stems. The enrichment of the three nutrient elements N, P and K in the leaves could improve the photosynthetic rate of A. mongolicus and provide enough material support for plant growth and reproduction, reflecting the resource allocation pattern and plant growth strategy. Along the natural precipitation gradient, the roots, stems and leaves of A. mongolicus mainly showed a synergetic relationship. The content of N and P in each organ showed an upward trend with the increase of precipitation, while K showed a downward trend. A. mongolicus responded to the drought stress environment by increasing the content of K in each organ and reducing the content of N and P, indicating that there is an ecological strategy of simultaneous investment between the roots, stems and leaves of A. mongolicus. The ratio of N: P in each organ was relatively stable among different precipitation gradients. A. mongolicus counteracts the changes of element content with the environment by coordinating nutrient conservation strategies in a conservative way. The nutrient synergy between organs was much higher than that within organs. The N:P ratios of organs were all greater than 16, indicating that the growth of A. mongolicus was mainly limited by P. Conclusion The stoichiometric characteristics of N, P, K in each organ have the same trend along the rainfall gradient, but show significant differences among different organs. The flexibility of stoichiometry is an important way to achieve plant self-regulation, which helps plants maintain their normal life activities under different environmental conditions.
, Available online , doi: 10.12403/j.1001-1498.20220420
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Objective To achieve the rapid and effective identification and identification of M. medusae and M. larici-populina. Methods In this study, several sets of primers for loop-mediated isothermal amplification (LAMP) were designed based on the 28S ribosomal DNA gene of two rust fungi. The putative primers selected from experiments were employed for LAMP reactions, and for the specific detection with the controls of genomic DNA from M. medusae, M. larici-populina, Sawadaia tulasnei, Erysiphe paeoniae, Gymnosporangium asiaticum, Morchella esculenta and Flammulina velutipes. The initial LAMP reaction system was established firstly and then the reaction system components and reaction conditions were further optimized. Hydroxynaphthol blue dye (HNB) was supplied into the reaction system to realize visual detection. Finally the sensitivity of the detection system was determined by the lowest DNA substrate. Results The results showed that the selected primers had specificity-species. The optimal Mg2 + concentration in the 25 μL LAMP detection system for M. medusae was 6 mmol·L−1, the optimal internal and external primer ratio was 8:1, and the optimal dNTPs concentration was 1.2 mmol·L−1. Meanwhile, the correspondent case for M. larici-populina was 4 mmol·L−1, 6:1 and 1 mmol·L−1. And all reaction products could be clearly detected with 160 μM hydroxynaphthol blue dying（HNB）. The two rusts detection system can be visually determined at 61 ℃ for 30 min and 40 min, respectively, each corresponding to the lowest DNA substrate concentration of 34 fg/μL and 60 fg/μL. Conclusion Through establishing a visual LAMP-HNB detection system, M. medusae and M. larici-populina can be identified and differentiated by the LAMP technology. This study provides a technological support in practice for rapid detection of the important poplar rust diseases.
, Available online , doi: 10.12403/j.1001-1498.20220541
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Objective To clarity the impact of phosphorus content in water on the migration and transformation of heavy metals in the soil of the alternating dry-wet fluctuation zone is of great significance for the prevention and control of heavy metals in the soil of the Three Gorges Reservoir area. Method In this paper, 6 sampling points in Xiangxi River reservoir bay, including fluctuation zone and upper edge soil were selected to collect samples. Soil and water samples were monitored for 4 quarters (June 2020 to March 2021) with water phosphorus and soil heavy metals Pb and Cd. In the indoor dry-wet alternation simulation test, 6 phosphorus additions were set up according to the range of phosphorus concentration in Xiangxi River and with the soil of its fluctuation zone. And soil water volume ratio was 1:2. Result The results showed that total phosphorus in Xiangxi River water was significantly positively correlated with Pb (P<0.05). Effective Pb was significantly positively correlated with effective Cd (P<0.01). The total phosphorus content in the water increased significantly (P<0.05) with increasing dry-wet alternation times. The total phosphorus content of soil in the flooding period was higher than that in the drying period when added concentration of phosphorus was lower than 0.2 mg·L−1 during the second flooding and drying period. Pb and Cd in the soil showed a transition trend from a highly mobile exchangeable state to a weakly mobile residual state; adding low concentrations of phosphorus (0.05 mg·L−1), the soil Pb content decreased significantly (P<0.05), and the soil Cd content increased with the increase of water phosphorus concentration (P<0.05), especially the form change of Cd was more significant and related to the water phosphorus content. Conclusion There is a migration and transformation of phosphorus between water and soil in the process of dry wet alternation. Phosphorus in the water promote the migration of Pb from soil to water, while inhibiting the migration of Cd from soil to water.
, Available online , doi: 10.12403/j.1001-1498.20230175
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Objective To study the changes of growth indicators, physiological and biochemical characteristics, and nutrient element content of Acacia melanoxylon R.Br. under different boron content, and reveal the response mode of A.melanoxylon to boron stress environment. Method The A.melanoxylon clone SR17 1-month-old seedlings were cultured with nutrient solution containing 0 , 0.1, 1, and 2 mmol·L−1 boric acid for 2 months. The changes in the physiological and biochemical indexes, such as growth index, chlorophyll content, physiologically active substances content, oxidoreductase activity, and nutrient element content, were determined under each culture condition. Based on principal component and subordinate function analysis, the contribution rate of each index for A.melanoxylon response to different contribution boron content was comprehensively evaluated, and the stress degree of A.melanoxylon seedlings with different boron supply levels was compared. Result The results showed that 0, 1, and 2 mmol·L−1 boron supply inhibited the increase of plant height and root length, reduced the aboveground chlorophyll content, and caused leaf degreenization, yellowing, and even abruption phenotypes. 0 mM boron made the primary and lateral roots white and thickened, 1 and 2 mmol·L−1 boron made the roots brown. The dosages of 0 , 1, and 2 mmol·L−1 boron reduced the content of ascorbic acid (AsA) and caused an oxidation reaction. The contents of malondialdehyde (MDA) and proline (Pro) were increased, leading to increased lipid oxidation levels and osmotic stress. It increased the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), lipoxygenase (LOX), and phenylalanine ammonlyase (PAL) in vivo, leading to the accumulation and removal of oxygen-free radicals and hydrogen peroxide (H2O2) as well as the synthesis of secondary metabolites. The increases of boron content of A.melanoxylon promoted the increase of phosphorus and potassium content, and the calcium content was the highest under 0.1 mmol·L−1 boron supply. Through principal component and subordinate function analysis, fourteen indexes, including potassium content, leaf number increase, plant height increase, LOX activity, AsA content, calcium content, boron content, POD activity, Pro content, SOD activity, root length increase, protein concentration, PAL activity, and chlorophyll b content, could be used as the main indexes of A.melanoxylon growth and development response to boron stress. Conclusion A.melanoxylon seedlings grow better under 0.1mmol·L−1 boron supply, and their growth indicators, physiological and biochemical characteristics, and nutrient element content are significantly different under different boron supply conditions. A.melanoxylon responds to boron stress by regulating plant phenotype, the content of physiologically active substances, oxidoreductase activity, and nutrient element content.
, Available online , doi: 10.12403/j.1001-1498.20220585
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: Objective To Identify the pathogen causing leaf spot of Cinnamomum camphora in Wanzhou District, clarify the characteristics of mycelium growth, and select fungicides that effectively inhibit the pathogen for providing a theoretical basis for prevention and control of leaf spot disease. Method The pathogen was isolated and purified by the tissue separation method, and the pathogenicity was tested by Koch's method. Pathogens were identified based on morphological characteristics and multilogues phylogenetic analysis combined with ITS, tub2, GAPDH, and ApMat genes; The hyphae growth rate method was used to study the characteristics of mycelium growth, and the fungicides were selected. Result The isolated strains were grayish and the edge was white when the mycelium was cultured on PDA medium for 3 days. The orange conidiomata appeared in the late. The conidia were long oval, blunt round at both ends, transparent and colorless were independent cells. The measured spore size was (9.8～18.6) μm × (4.2～6.0) μm; Pathogenicity of strain ZT-1 was tested by two methods, both of which could cause the leaf spot disease of C. camphora leaves; The representative strains ZT-1 and ZT-5 clustered with Colletotrichum gloeosporioides, and the reliability was 100%; The optimum growth temperature of the pathogen was 28 ℃; The optimum pH value was 6.0; Potato Dextrose Agar medium was beneficial to mycelial growth; The optimum carbon and nitrogen sources were glucose and glycine; The optimum lighting condition was total darkness. Among the five chemical and biological fungicides, 15% triadimefon WP and 1% osthol EW were highly toxic and the inhibition effect of C. gloeosporioides was obvious. Their EC50 values were less than 10 μg · mL−1. Conclusion C. gloeosporioides is the pathogen causing anthracnose on C. camphora in Wanzhou District and 15% triadimefon WP can be used as a fungicide for control.
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, Available online , doi: 10.12403/j.1001-1498.20230122
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:[ Objective ] To explore the soil fertility of forest land in the main production area of Carya dabieshanensis, and provide basis for soil management and scientific fertilization of forest land of C. dabieshanensis. [ Method ] 88 soil samples were collected from the main producing areas of C. dabieshanensis in Jinzhai County, Huoshan County and Luotian County. According to the indicators of pH, organic matter, Total N, Toal P, Total K, Available N, Available P and Available K, the soil fertility was evaluated by fuzzy comprehensive evaluation method, and its content and variation were analyzed. [ Results ] The average soil pH value of Carya dabieshanensis was 5.19; The contents of soil organic matter, Total P, Available N and Available P were generally rich, with an average of 53.11 g·kg−1, 0.99 g·kg−1, 179.41 mg·kg−1 and 21.30 mg·kg−1, respectively. The average value of Total N was 1.02 g·kg−1, at a medium content level. The contents of soil Total K and Available K were relatively deficient, with an average of 8.24 g·kg−1 and 71.52 mg·kg−1. The average value of comprehensive index of soil fertility (IFI) of C. dabieshanensis was 0.61. Both Grade II and III soils accounted for 50.00%. Principal component analysis showed that organic matter, Available N, Total P, Available P, pH and Total K were the most important factors affecting soil comprehensive fertility. [ Conclusion ] The comprehensive soil fertility of forest land in C. dabieshanensis is generally high. The contents of organic matter, Available N and phosphorus are rich, the pH value is acidic, and potassium is deficient. Soil management should improve the soil to increase the pH value, increase potassium fertilizer, maintain phosphorus fertilizer and reduce the use of nitrogen fertilizer.
:[ Objective ] To explore the soil fertility of forest land in the main production area of Carya dabieshanensis, and provide basis for soil management and scientific fertilization of forest land of C. dabieshanensis. [ Method ] 88 soil samples were collected from the main producing areas of C. dabieshanensis in Jinzhai County, Huoshan County and Luotian County. According to the indicators of pH, organic matter, Total N, Toal P, Total K, Available N, Available P and Available K, the soil fertility was evaluated by fuzzy comprehensive evaluation method, and its content and variation were analyzed. [ Results ] The average soil pH value of Carya dabieshanensis was 5.19; The contents of soil organic matter, Total P, Available N and Available P were generally rich, with an average of 53.11 g·kg−1, 0.99 g·kg−1, 179.41 mg·kg−1 and 21.30 mg·kg−1, respectively. The average value of Total N was 1.02 g·kg−1, at a medium content level. The contents of soil Total K and Available K were relatively deficient, with an average of 8.24 g·kg−1 and 71.52 mg·kg−1. The average value of comprehensive index of soil fertility (IFI) of C. dabieshanensis was 0.61. Both Grade II and III soils accounted for 50.00%. Principal component analysis showed that organic matter, Available N, Total P, Available P, pH and Total K were the most important factors affecting soil comprehensive fertility. [ Conclusion ] The comprehensive soil fertility of forest land in C. dabieshanensis is generally high. The contents of organic matter, Available N and phosphorus are rich, the pH value is acidic, and potassium is deficient. Soil management should improve the soil to increase the pH value, increase potassium fertilizer, maintain phosphorus fertilizer and reduce the use of nitrogen fertilizer.
, Available online , doi: 10.12403/j.1001-1498.20230140
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Objective This study explores the relationships between stand density, crown structure and crowding, in order to deeply clarify the structural characteristics of Quercus mongolica secondary forest for providing sufficient scientific basis for sustainable forest management in the future. Method In August 2020,typical plots with similar site conditions and different stand densities were selected from the secondary mixed forest of Quercus Mongolicus in Xiaolong Mountains to analyze the relationship between crown structure and crowding under different stand densities by using Pearson correlation analysis and structural equation model. Result There were differences in the crown structure characteristics of Quercus mongolicus forest with different stand densities. The variation in crown volume was the strongest, followed by crown length and crown area. The variation in crown width, crown length ratio and crown shape ratio was the weakest. The variation trend in crown structure characteristics showed a unimodal distribution with changes in stand density. With the decrease of stand density, the correlation trends of crown width, crown area and crown volume with DBH were similar to "L" pattern, while the correlation between crown length and DBH were consistent with the change in stand density, and the effects of stand density on the correlation between crown length rate, crown shape rate and DBH was not significant. The crowding of the Quercus mongolica forest ranged from medium dense to very dense, but the crowding in different density stands was different. The dominant species of Quercus mongolica, Betula platyphylla, Pinus armandii and Tilia tuan dominated the crowding. The influence of stand density on the relationship between crown structure and crowding in Quercus mongolicus forest could be divided into two ways: forest competition - indirect effects mediated by crown structure; The indirect impact mediated by forest competition, diameter at breast height, and crown structure. Conclusion The crown structures of Quercus mongolica forest vary with different stand densities. Crown structure is related to the DBH. The relationship between crown structure and crowding of Quercus mongolicus forest is finally affected by stand density. In order to achieve sustainable management of the Quercus mongolicus secondary forest, we should not only consider the DBH, but also pay attention to the characteristics of the crown structure. By adjusting stand density, we can optimize the crown structure and improve the crowding state to promote forest regeneration and increase species diversity.
, Available online , doi: 10.12403/j.1001-1498.20230026
Abstract:
Objective The role of MYB transcription factor family in the drought stress response of Phyllostachys edulis was analyzed to provide candidate genes for stress resistance improvement and molecular breeding of moso bamboo. Method In this study, the gene sequence of PheMYB2R-4 was obtained from the genome database of Phyllostachys edulis, and the molecular characteristics of PheMYB2R-4 was analyzed by subcellular localization and transcriptional activity experiments. The function of PheMYB2R-4 was confirmed by qRT-PCR, phenotype analysis of transgenic Arabidopsis thaliana and determination of stress-related physiological and biochemical indicators. Result PheMYB2R-4 encoded a protein with 305 amino acids, which had a conservative R2R3 domain in its N-terminal region and belonged to the R2R3-MYB subfamily. The expression of PheMYB2R-4 gene was significantly induced by drought and salt. PheMYB2R-4 was a nuclear localization protein and had transcriptional self-activation activity. The overexpression of PheMYB2R-4 increased the relative water content of Arabidopsis thaliana leaves under drought stress and decreased the relative conductivity and the accumulation of malondialdehyde, indicating that the overexpression of PheMYB2R-4 enhanced the drought tolerance of transgenic Arabidopsis thaliana by improving its water retention capacity and reducing oxidative damage. At the same time, under drought stress, AtRD22, AtRD29A, AtDREB2A and AtLEA were all up-regulated. Conclusion PheMYB2R-4 has a positive regulatory role in the response to drought stress, which can improve the drought tolerance of plants and enhance the expression of drought response genes.
, Available online
Abstract:
Objective To investigate and analyze the host species of bacterial canker of Populus × euramericana, the disease-resistant varieties and the possible disease-resistant substances they contain. Method The host of the pathogen and the resistant varieties were determined by field investigation and inoculation tests. The content of active substances in the bark of disease-resistant and susceptible varieties was analyzed by HPLC. Result The hosts of bacterial pathogen of P. × euramericana canker are P. deltoides, P. × euramericana and Salix matsudana. P. × euramericana cl. 'Zhonglin 46', P. deltoides cl. '2025', P. × euramericana cv. '2001', P. deltoides cl '313', P. deltoides 'Zhonghe-1' and P. deltoides '16-09' were highly susceptible to the bark canker disease; P. × euramericana 'Yukang 1' and P. deltoides '16-10' were highly resistant varieties, P. deltoides '131', P. deltoides '03-59', P. deltoides '02-212' and P. deltoides '03-34' were resistant varieties. Hybrid willows and Salix babylonica are resistant to the pathogen, and Salix × aureo-pendula can be affected, but do not cause serious disease. The HPLC analysis showed that the contents of catechol, benzoic acid and chlorogenic acid in the bark of resistant and highly susceptible poplar varieties were significantly different. The catechol and catechin increased when the hosts were infected by Lonsdalea populi. Conclusion In this study, the host species of bacterial canker of P. × euramericana are determined, and resistant and highly susceptible poplar varieties are screened. It is showed the catechol and catechin are important compound for host to defense the pathogen infection. The results will be helpful to the control of the bacterial disease of poplar.
, Available online
Abstract:
Objective To understand the effect of litter of Castanopsis kawakamii natural forest on the competitive intensity of regeneration of Pinus massoniana. Method The allelopathic effects of litter extract of natural forest with different concentration and decomposition degree on seed germination and radicle growth of P. massoniana were studied. Result (1) The main factor affecting the germination of P. massoniana seeds was the degree of litter decomposition. Compared with the blank control, the litter of undecomposed layer and fully decomposed layer had no significant effect on the germination of P. massoniana seeds; the semi-decomposed layer inhibited the germination rate and germination index and promoted the germination potential. (2) The main factors affecting the growth of radicle were the concentration and action time of litter extract, and the effect of undecomposed layer on the whole radicle growth period of P. massoniana seeds was enhanced with the decrease of concentration, but increased with the decrease of concentration, and the promoting effect was the strongest at the concentration of 1 ≤ 100, and the effect of semi-decomposition layer was promoted by low concentration and high concentration, and the intermediate concentration was inhibited by the undecomposed layer. The fully decomposition layer showed promoting effect as a whole, and the promoting effect decreased with the decrease of concentration. (3) Correspondence analysis showed that different decomposition degree-concentration had no significant effect on seed germination of P. massoniana, but had significant correlation with radicle growth. Conclusion The result proves that the litter extract of different decomposition degree has a weak promoting or inhibiting effect on the seed germination of P. massoniana, promotes the growth of radicle at low concentration, and promotes the regeneration of P. massoniana, which will intensify the interspecific competition in the forest, and lead to the inhibition of the natural regeneration of C. kawakamii.
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