2023 Vol. 36, No. 6
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2023, 36(6): 1-10.
doi: 10.12403/j.1001-1498.20230157
Abstract:
Objective To explore the effects of desiccation on the anatomical structure of somatic embryo of Picea asperata, identify the key genes that lead to the changes in anatomical structure, and preliminarily explore the reasons why desiccation promotes somatic embryo germination. Method The high embryonic cell line of Picea asperata was used to induce somatic embryogenesis. The phenotypic observation and germination rate of somatic embryos were determined after desiccation treatment for different time. Ultra depth of field microscope, scanning electron microscope and transmission electron microscope were used to observe the differences of tissue and cell structure and morphology between desiccated somatic embryos and non-desiccated somatic embryos, and transcriptome sequencing was combined to analyze the changes of gene expression between desiccated and non-desiccated somatic embryos. Results The somatic embryo morphology of spruce was significantly changed after desiccation. The radicle turned red and the cotyledon turned green after desiccation. Microscopic observation showed that the cells of the desiccated somatic embryo were shrunken and irregularly distributed. At high magnification, the cell wall was no longer rigid, showing a relaxed and twisted state. Transcriptome analysis found that several transcripts of XTHs, EXPAs and PMEs involved in cell wall remodeling and affecting the mechanical properties of cell walls were significantly differentially expressed between desiccated and non-desiccated somatic embryos, and their expressions were mostly up-regulated, which was consistent with the results of microscopic observation on the morphological changes of desiccated somatic embryos. These genes may synergically regulate the process of desiccation and affect the germination of somatic embryos. Conclusion The differential expression of cell wall remodeling genes during desiccation leads to the relaxation of somatic embryo cell wall, the disappearance of rigid structure, and the release of cell differentiation and growth restrictions, which is a potential reason for desiccation to promote somatic embryo germination.
2023, 36(6): 11-19.
doi: 10.12403/j.1001-1498.20230083
Abstract:
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 33 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 0.9, 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 the 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.
2023, 36(6): 20-29.
doi: 10.12403/j.1001-1498.20230039
Abstract:
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.
2023, 36(6): 30-39.
doi: 10.12403/j.1001-1498.20230079
Abstract:
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 L. 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 ITS, gpd and EF-1α sequences, the isolate YP4 fell into the S. lycopersici clade with strong support. Based on the pathogenicity measurement of Koch's rule, the strain YP4 was pathogenic to leaves of L. japonica and S. 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 S. lycopersici. To our knowledge, this is the first report of S. lycopersici causing black spot of L. japonica in China.
2023, 36(6): 40-47.
doi: 10.12403/j.1001-1498.20230133
Abstract:
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.
2023, 36(6): 48-57.
doi: 10.12403/j.1001-1498.20230147
Abstract:
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.
2023, 36(6): 58-68.
doi: 10.12403/j.1001-1498.20230214
Abstract:
Objective To explore the characteristics of soil bacterial community diversity and structure with the treatment of conversion 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.
2023, 36(6): 69-77.
doi: 10.12403/j.1001-1498.20230061
Abstract:
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.
2023, 36(6): 78-86.
doi: 10.12403/j.1001-1498.20230163
Abstract:
Objective To analyze the genetic diversity of the Cunninghamia lanceolata germplasms from Jiangxi Province, and a core collection of C. lanceolata was constructed. 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% Na, 107.4% Ne, 115.1% I, 109.0% H, 104.1% Ho, 110.0% He and 111.2% PIC of the original collection. 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.
2023, 36(6): 87-96.
doi: 10.12403/j.1001-1498.20220536
Abstract:
Objective To investigate the evaluation method of cold resistance of olive cuttings. Methods Eight two-year cuttage seedlings of olive varieties were introduced and planted in the valley of Bailong River on the southern slope of West Qinling Mountains in North subtropical China. Cold stress (16, 12, 8, 4, 0, −4 ℃) was simulated to measure the contents of osmotic regulation substances, protective enzyme activities, photosynthesis and chlorophyll fluorescence parameters. Results With the increase of cold stress, the contents of relative electrical conductivity (REC), proline (Pro), soluble sugar (SS) and soluble protein (SP) in the leaves of 8 tested olive varieties showed an increasing trend, and the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) increased before 0 ℃ and then began to gradually decreased after freezing point; During the process of temperature decrease, leaf chlorophyll content (Chl), net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr), maximum photochemical efficiency (Fv/Fm) and actual photochemical efficiency (ΦPSⅡ) of all varieties showed a decreasing trend,stomatal conductance (Gs) showed a decreasing trend before -4℃. Correlation analysis was conducted using three evaluation systems: semi-lethal temperature (LT50), membership functions of osmotic regulatory substances and protective enzymes, and membership functions of photosynthesis and chlorophyll fluorescence. The results showed that the semi-lethal temperature of eight olive varieties ranged from -16.359 ℃ to -9.715 ℃. Conclusion The comprehensive ranking of cold resistance obtained by the method of subordinate function of the activity parameters of osmotic regulatory substances and protective enzymes is basically consistent with the ranking of semi-lethal temperature obtained by the method of conductivity and Logistic equation, and is consistent with the overwintering performance of olive in the test area. It can be used as an evaluation method for cold resistance of olive at seedling stage.
2023, 36(6): 97-105.
doi: 10.12403/j.1001-1498.20230037
Abstract:
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 had 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 had 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.
2023, 36(6): 106-114.
doi: 10.12403/j.1001-1498.20230060
Abstract:
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 index (DPI) 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.
2023, 36(6): 115-125.
doi: 10.12403/j.1001-1498.20230159
Abstract:
Objective To explore the optimal media components at stages for callus induction, adventitious bud differentiation, rooting induction of indirect organogenesis, a high-frequency regeneration system of Betula alnoides was established for providing theoretical evidence and technical support for genetic transformation and multiplication of elite cultivars of this species. Methods The internode stem segment of Betula alnoides TC2 clone was used to conduct callus induction, adventitious bud differentiation and rooting medium screening experiments, and the pre-culture conditions were optimized, revealing the fundamentals of callus induction stage. The effects of basic media, application of hormones, and dark culture at callus induction stage, hormone combination at adventitious bud differentiation stage, and preculture conditions on adventitious bud differentiation were assessed. Results (1) The suitable conditions for preculture were: 15 days under low illumination (1 000 lx), then 7 days in dark and 8 days under normal illumination (2 000 lx), and properly yellowing plantlets could be obtained under these conditions with the mean height and internode length reaching 6.57 cm and 3.07 cm, respectively; (2) The medium suitable for callus induction of internodes was WPB5 + 1.0 mg·L−1 TDZ + 0.2 mg·L−1 NAA + 20 sucrose + 5.8 g·L−1Agar (pH5.8) for the callus induction, and the optimal dark culture time was 15 days; (3) The medium suitable for callus differentiation was WPM + 0.8 mg·L−1 6-BA + 0.5 mg·L−1 GA3 + 30 sucrose + 5.8 g·L−1Agar (pH5.8); (4) Using the above optimal scheme, the differentiation rate and net proliferation coefficient of the internode segments were 88.89% and more than 6.2, respectively, and 56.8 adventitious buds were obtained eventually per preculture plantlet on average; and (5) The reasonable rooting medium was the Wood Plant Medium supplemented with 0.2 mg·L−1 NAA + 20 g·L−1 sucrose, and the rooting rate could reach 100% after 30 days. Conclusion A high-frequency regeneration system of B. alnoides is completely established with high stability and good repeatability in the study. It can not only has a high callus differentiation rate and proliferation coefficient, but also improves the efficiency of internode production. The findings can provide a technical support for tissue culture and future genetic improvement through genetic engineering of B. alnoides.
2023, 36(6): 126-133.
doi: 10.12403/j.1001-1498.20230012
Abstract:
Objective To Investigate the defensive response to walnut 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 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.
2023, 36(6): 134-143.
doi: 10.12403/j.1001-1498.20230194
Abstract:
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.
2023, 36(6): 144-150.
doi: 10.12403/j.1001-1498.20230164
Abstract:
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 (GA3), 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 the change in the ratios of IAA/ABA and ZR/ABA. The contents of GA3, IAA, and ZR in the endosperm decreased 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/ABA in 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.
2023, 36(6): 151-161.
doi: 10.12403/j.1001-1498.20230207
Abstract:
Objective Reasonable planting density and canopy structure can effectively improve the photosynthetic efficiency and growth of forest trees. The study of leaf photosynthetic characteristics of Cunninghamia lanceolata seedlings in different canopy layers, directions and branch positions under different planting densities can provide theoretical basis for scientifically defining reasonable planting density and pruning height of C. lanceolata in the cultivation of large-diameter classless trees. Method Three standard trees were selected from five plots with planting density (M1: 833、M2: 1667、M3: 2500、M4: 3333、M5: 6667 tree·hm−2) , there are five different canopy layers (1, 2, 3, 4, 5 m away from the base of the tree), two different orientations of branches (east and west, north and south), and two different parts of branches and leaves (tips and endings).The net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs) were measured, and water use efficiency (WUE) was calculated. Result 1) At 2 m of the canopy, the Pn and WUE decreased with the increase of planting density, and the Pn, Gs, Tr, and WUE increased first and then decreased at 3~5 m of the canopy. 2) the Pn, Gs, Tr, and WUE increased significantly with the increase of canopy, and the light condition of branches and leaves at 5 m of canopy was sufficient and photosynthesis was strong. 3) Except for the leaves at 2 to 3 m of the canopy under M4 and M5 densities, Pn, Gs, Tr, and WUE in terminal leaves were larger than those in tip leaves at different branch positions, Pn, Gs, Tr, and WUE in the remaining leaves under different canopies and different densities showed the order of tip leaves > terminal leaves in different branch locations. Conclusion Among the five planting densities, the leaves at M2 density (1667 tree·hm−2) have stronger photosynthetic capacity in different canopy and branch directions. In the four canopies, the leaves at 5 m of the canopy showed greater photosynthetic potential. The photosynthetic capacity of the tip leaf was stronger than that of the terminal leaf, and that of the east-west branch leaf was stronger than that of the south-north branch leaf. The net photosynthetic rate of branches and leaves in the canopy 2 m and 3 m of M5 planting density (6667 tree·hm−2) and 2 m of M4 density (3333 tree·hm−2) showed a negative value in C. lanceolata, that is, the increase of density will have an impact on the light resources in the forest, especially in the branches and leaves in the low canopy. The higher the density, the more obvious the impact on the canopy.
2023, 36(6): 162-171.
doi: 10.12403/j.1001-1498.20230029
Abstract:
Objective To explore the potential hazard of W. carpophilus on other major tree species in Xinjiang, and to improve the diagnosis and detection efficiency of this disease, Method in this paper, W. carpophilus was inoculated into healthy leaves of 19 plants in six families by ex vivo leaf inoculation, and its pathogenicity and host range were preliminarily determined; Specific primers for W. carpophilus were designed with reference to the tef1 sequence; 76 strains of W. carpophilus and 22 other fungi were specifically and sensitively detected by conventional PCR and real-time PCR, and the reaction system of real-time PCR was optimized; In addition, the designed specific primers were used to perform conventional PCR on natural onset samples in the field. Samples and wild apricot leaf samples 7, 10, 13, 16, 19, 21, 24 and 48 h after artificial inoculation were used for routine PCR detection. Result The leaves of 15 plants inoculated showed obvious lesions after 5 d of inoculation, with extremely significant differences (P＜0.01) in lesion size between different hosts, with the largest lesion size of up to 28.99 mm2 in Xinjiang leaflet white wax, and only four plants, namely, Prunus. cistena, Crataegus chlorocarpa, Populus alba var. pyrmidalis, Morus alba var. tatarica, were not involved. The specific primers W0404-14-F/ W0404-14-R designed in this study were able to amplify a specific band at 113 bp for W. carpophilus but not for other fungi. The sensitivity of the conventional PCR assay was 5.99 × 10−1 ng·μL−1. W. carpophilus could be detected within the leaves 10 h after inoculation of Wild Apricot Leaves by conventional PCR. Conclusion W. carpophilus can harm 15 other tree species and is potentially harmful; PCR assay is rapid and specific for the detection of W. carpophilus. This study is the first time to explore the potential host range of W. carpophilus and a rapid PCR assay for the diagnosis and detection of porokeratosis caused by W. carpophilus.
2023, 36(6): 172-180.
doi: 10.12403/j.1001-1498.20230081
Abstract:
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.
2023, 36(6): 181-191.
doi: 10.12403/j.1001-1498.20230175
Abstract:
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.
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