2018 Vol. 31, No. 5
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2018, 31(5): 1-8.
doi: 10.13275/j.cnki.lykxyj.2018.05.001
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Abstract:
Objective To provide comprehensive genetic information for the development of microsatellite markers and the mining of functional genes in Phyllanthus emblica by characterizing the transcriptome of P. emblica in dry-hot valleys in Yunnan. Method Transcriptome sequencing was conducted on young leaves of Ph. emblica using Illumina Hiseq 4000, followed by filtering, de novo assembly and clustering. Sequence similarity analysis and annotation of the obtained Unigenes were performed based on databases like NCBI-non-redundant (NR) protein database, Gene Ontology (GO), Clusters of Orthologous Groups (COG), KEGG database, SwissProt, PlantTFDB, and PRGdb. Result In total, 10.52 Gb Clean reads with Q20 of 98.47% and Q30 of 95.28% were generated. A total of 76 881 Unigenes with an average length of 713 nt and N50 of 1 257 nt were obtained by de novo assembly and clustering with Clean reads. Out of them, 44 768 Unigenes were functionally annotated against four protein databases. The Unigenes were roughly divided into 25 categories according to COG function, and were grouped into three functional categories (including biological processes, cellular components and molecular function) and 47 sub-categories based on GO functional annotation. KEGG analysis showed that the Unigenes could be fallen into six categories and 21 metabolic pathways, of which about 3/5 were Metabolism. A total of 42 953 CDS were detected based on the results of functional annotation, and 2 058 CDS were predicted using ESTScan with the remaining Unigenes. And 56 Transcription Factor families and 18 resistance genes were predicted. Conclusion The Unigenes of transcriptome in Ph. emblica show high quality, good integrality, abundant genes and various functions, which could lay an important foundation for further study of functional gene excavation, resistance mechanism analysis, molecular marker development and molecular assisted breeding of Ph. emblica and other congeneric species.
2018, 31(5): 9-19.
doi: 10.13275/j.cnki.lykxyj.2018.05.002
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Objective The transcriptome data of Pinus massoniana under drought stress were used to clarify the function distribution of sequences, as well as the characteristics and distribution patterns of SSR loci, and to explore the key SSR loci linked to drought-resistant gene. Method The P. massoniana needle samples under lingering drought stress for 10, 15, and 25 days and the corresponding samples with sufficient water as the control (CK) were selected to extract the total RNA. Illumina sequencing were performed to generate raw reads. After removal of low-quality data, the transcriptome assembly was conducted using Trinity software. The unigenes of transcriptome were annotated by aligning with several public databases via BLAST program, including GO (Gene Ontology), KOG (eukaryotic orthologous groups), and KEGG (Kyoto Encyclopedia of Genes and Genomes). The SSRs loci were examined using Misa software, and the PCR amplification SSR primers were designed using Primer 3.0 software. GO and KEGG enrichment analysis were implemented using GOSeq (1.10.0) and KOBAS software, respectively, to determine the major process of biological process and metabolic pathways of differentially expressed unigenes contained SSR loci. Result A total of 101 806 unigenes were annotated from 194 821 unigenes of transcriptome. Among them, 64 973 functional annotations were from GO database, 35 880 from KOG database and 30 882 from KEGG database. Moreover, 6 728 SSR loci were identified and distributed in 6 367 unigenes, and their average frequency of SSRs was 3.45%. Among all the SSR motifs, mononucleotide, trinucleotide and dinucleotide were the major repeated types, with occurrence frequency of 35.82%, 33.03% and 25.22%, respectively; the form of A/T, AT/AT, AG/CT, AGC/CTG, and AAG/CTT were the most frequent motifs, the length from 10 to 20 bp were the most repeat motifs, and the SSR repeat numbers from 5 to 10 were the most repeat numbers of motifs. A total of 13 338 pairs of SSR primers were designed for marker development of P. massoniana. Furthermore, among the 6 367 unigenes containing SSR loci, 422 unigenes were differentially expressed on drought stress versus the control. Enriched analysis of KEGG pathway showed that 11 unigenes containing SSR loci were significantly enriched into three KEGG pathways, including photosynthesis, plant hormone signal transduction and carotenoid biosynthesis, which were linked to the plant response to drought stress. Conclusion A total of 101 806 unigenes were annotated from a higher quality of transcriptome database in P. massoniana, 6 728 SSR loci were identified and distributed from 6 367 unigenes, 11 SSR loci from 422 differentially expressed genes containing SSR loci were identified linking to the plant response to drought stress. These results can be used for the subsequent study on molecular mechanism for drought resistance and functional gene localization in P. massoniana.
2018, 31(5): 20-26.
doi: 10.13275/j.cnki.lykxyj.2018.05.003
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Objective The adaption and growth variation of the species and provenances in Picea were tested in order to select the suitable species and provenances for interior cultivation. Method Early evaluation experiments in twenty provenances of six species including Picea abies, P. mariana, P. glauca, P. pungens, P. koraiensis and P. crassfolia in Xiaolongshan Shaba Experimental Base in Gansu province were carried out. The variation and correlation were made on the height, diameter at ground-level (Dg), height increment and crown at 6, 7 and 9 years old. Result The differences among the growth traits of the species and provenances in Picea at the age of 6, 7 and 9 years old were all extremely significant, indicating larger genetic variation existed among the species and provenances. Seven elite provenances were selected using height and diameter as the main traits. The realized genetic gain of their height and diameter were bigger than 11%. There was significantly positive correlation between height and latitude or longitude for P. abies, P. glauca and P. mariana. The average height of P. abies or P. glauca had negative correlation with the elevation, but no correlation between the average height of P. mariana and elevation. Conclusion The best provenances of P. abies, P. glauca, and P. mariana derived from latitude 49°16'~58°38'N and longitude 68°13'~118°24'W are suitable to be introduced and cultivated in Xiaolongshan of Gansu province.
2018, 31(5): 27-32.
doi: 10.13275/j.cnki.lykxyj.2018.05.004
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Objective To study the effects of warming on nitrogen cycle and water use efficiency by isotopic method, and to explore the response of the water use efficiency and the nitrogen saturation state of subtropical Cunninghamia lanceolata juveniles grown in subtropical region to global warming. Method The experimental site is located in the Global Change Experimental Platforms, in Sanming of Fujian Province, China. The heating cables were used to artificially induce the warming. The treatments of control (CT) and warming (W) were set up. The leaves of C. lanceolata and surface soil (0~10 cm depth) were sampled to examine the contents of their stable N and carbon (C) isotopes, i.e., δ15N and δ13C, and the contents of C and N. Result Compared to the control treatment (-2.79‰), the foliar δ15N of the warming treatment (0.40‰) significantly increased by 3.19‰; but no significant difference was found in the leaf N contents between the control and the warming treatments. After warming, there was a significant increase in surface soil δ15N, and leaf 15N enrichment index was closer to 0 compared to that in the control treatment. The foliar δ13C of the warming and control treatments were -29.35‰ and -29.08‰, respectively. There was a significant positive correlation between foliar δ15N and δ13C. Conclusion These findings suggest that the temperature is an important factor affecting N cycling in subtropical regions. Warming can increase leaf and soil δ15N significantly, and the metabolism of carbon and nitrogen complement each other.
2018, 31(5): 33-41.
doi: 10.13275/j.cnki.lykxyj.2018.05.005
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Objective Considerable researches have documented the negative effects of O3 on woody species in North America and Europe, however, little is known about how woody tree species respond to elevated O3 in subtropical China. The objectives of this study are to investigate the effects of elevated O3 on two evergreen tree species in subtropical China, and compare the O3 sensitivity between them and explore potential mechanisms on differential responses to O3. Method One-year-old seedlings of Phoebe zhennan S. Lee et F. N. Wei and Phoebe bournei (Hemsl.) Yang were exposed to non-filtered air, 100 nmol mol-1 O3 air (E1) and 150 nmol mol-1 O3 air (E2) to investigate the O3 effects on photosynthesis, antioxidant capacity and biomass of these two species. Result The results are as follows:(1) O3 fumigation reduced net photosynthesis rate (Pn) mainly through non-stomatal factors in both species. Pn was lower under E2 than that under E1 in P. zhennan. Whereas for P. bournei, Pn was greater under E2 than that under E1 in August measurement, while the reverse patterns were observed in the measurements in September and October. (2) O3 fumigation increased measured antioxidant substances levels in both species. The levels of total phenols and total antioxidant capacity increased with O3 concentrations increasing. However, reduced ascorbic acid contents were lower under E2 than that under E1. (3) O3 fumigation decreased root, stem, foliage and total biomass in both species. The reduced below/above ground biomass ratio was only observed in P. bournei. Conclusion O3 fumigation decreases photosynthesis, increases the antioxidant capacity, and ultimately inhibits the growth of the two species. The O3 sensibility of P. bournei is stronger than that of P. zhennan based on Pn and biomass. The differential sensitivity to O3 is related to (i) stomatal conductance, and (ii) antioxidant substances responses to elevated O3 and their background level.
2018, 31(5): 42-49.
doi: 10.13275/j.cnki.lykxyj.2018.05.006
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Objective To further study the mechanism of ThbHLH1 overexpression on improving the salt and drought tolerance of Tamarix hispida. Method The cis-acting elements recognized by ThbHLH1 were identified with the transcription factor-centered yeast one hybridization (TF-centered Y1H) method. To confirm the results of TF-centered Y1H, the effector construct 35S:ThbHLH1 was co-transformed with each reporter constructs pCAM-Cis into tobacco leaves with the particle bombardment method, and then the GUS activity was determined under salt or drought stress. Result ThbHLH1 could recognize LTRE1 (CCGAAA) and WRKY710S (TGAC) Cis-acting elements. Conclusion The results show that ThbHLH1 activates gene expression under salt or drought stress by interacting with LTRE1 or WRKY710S motifs.
2018, 31(5): 50-56.
doi: 10.13275/j.cnki.lykxyj.2018.05.007
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Objective This study aims to provide reference for revealing the role of steroid 22-alpha hydroxylase in moso bamboo (PeDWF4) in the response to abiotic stresses, based on the analysis of its gene structural characteristics and expression patterns. Method The method of homologous sequence comparison was used to isolate the homologous gene of DWF4 in moso bamboo with the information in BambooGDB. Bioinformatic method was used to analyze the gene structure, the basic physical and chemical characteristics, the conservative domains in the protein encoded by the gene, and the evolutionary relationships, etc. Besides, RT-PCR was applied for the gene expression analysis in different bamboo tissues and real-time fluorescent quantitative PCR (qRT-PCR) was conducted to find the expression patterns of the gene in leaf blades under the stresses of high salt, drought, low temperature and high light, respectively. Result PeDWF4, a homologous gene of DWF4, was isolated from moso bamboo, whose open reading frame is 1 503 bp, and the corresponding genome sequence is 6 149 bp containing 8 exons and 7 introns. The introns completely conformed to the principle of GT-AG splicing. PeDWF4 encoded an alkaline protein with 500 aa, belonging to the single oxygenases of cytochrome P450 family. Tissue specific expression analysis showed that PeDWF4 was detected in all tissues of bamboo roots, stems, fully expanded leaf blades, not fully expanded leaf blades, leaf sheaths and shoots with different levels, among which the highest one was in leaf blades, followed by roots, while those in stems, sheaths and shoots were relatively lower. In accordance with the transcriptome data, PeDWF4 had the highest expression level in leaf blades. Both under NaCl (400 mmol·L-1) and drought stresses, the expression of PeDWF4 in leaf blade showed a trend of induction and then suppression. Under NaCl stress, it was upregulated to 3.5 times of the control after 2 hours, then decreased gradually with the prolonged processing and reached to nearly only 20% of the control after 6 hours. That under drought stress was upregulated to 2 times of the control after 1 hour, and decreased to 60% of the control after 8 hours. The expression of PeDWF4 was induced by both high light (1 200 μmol·m-2·s-1) and low temperature (4℃) stresses. Under high light stress, it was upregulated to 4.5 times of the control after 2 hours, then decreased gradually with the prolonged processing and reached to 2 times of the control after 8 hours. That under low temperature stress was upregulated to 3 times of the control after 1 hour, and then decreased gradually and reached to 2 times of the control after 8 hours. Conclusion PeDWF4, a DWF4 homologous gene is isolated from moso bamboo, which belongs to the single oxygenase gene of cytochrome P450 family. PeDWF4 is constitutively expressed in moso bamboo. The expression changes indicate that PeDWF4 is involved in response to NaCl, drought, low temperature and high light stresses, which might be helpful to improve the ability of moso bamboo to withstand abiotic stresses.
2018, 31(5): 57-63.
doi: 10.13275/j.cnki.lykxyj.2018.05.008
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Objective The ORF72 gene of Hyphantria cunea nuclear polyhedrosis virus belongs to the GIY-YIG endonuclease family, it has a high conservative sequence and is closely related to the viral DNA replication. Method An ORF72 gene was sub-cloned into the pGEX-4T-1 vector. The protein was over-expressed under different induced conditions and purified by GST-tag affinity chromatography column. Result It was proved that the recombinant vector was constructed successfully by the restriction map and DNA sequencing. SDS-PAGE gel electrophoresis detection showed that ORF72 protein could be integrated with GST-tag protein on the pGEX-4T-1 and the size of the expressed fusion protein was about 38.2 kDa. The induced conditions in over-expression of the recombinant proteins were optimized. The major recombinant protein was obtained by a feasible condition at 25℃ with 1.0 mmol·L-1 IPTG for 4 h. Moreover, the recombinant protein was expressed to high levels in the two strains of Escherichia coli BL21 and Rosetta, while the expression in the Rosetta strain was higher than BL21. Conclusion The recombinant ORF72 was purified using GST-affinity chromatography.
2018, 31(5): 64-73.
doi: 10.13275/j.cnki.lykxyj.2018.05.009
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Objective To evaluate the potential use of endophytes from extreme conditions as novel probiotics in improving salt tolerance of tree seedlings. Method The effects of three endophytic Fusarium isolates, recovering from the halophytic Leymus mollis, on the growth and salt tolerance of Liquidambar styraciflua seedlings were investigated. The three isolates were identified through morphological description and molecular phylogeny. In vitro toxin production of the endophytic Fusarium isolates were analyzed. The co-culturing system was used to investigate the binary interactions between gnotobiotic seedlings and Fusarium isolates under normal and saline conditions. Tissue staining method was applied to examine the fungal infection structures formed in roots. Result Two Fusarium isolates were identified to F. culmorum (Class2-1B) and F. pseudograminearum (Class2-1C), and the other one (Class2-3) was not currently identified to the species level. In comparison to two pathogenic Fusarium species, the Class2-1B and Class2-1C only produced very low level of several toxins, while the Class2-3 produced a large amount of enniatine. Both Class2-1B and Class2-1C exhibited an extensive colonization pattern in roots, but the hyphae of the Class2-3 seldom entered the inner root tissues and just distributed around the root surface. Inoculation experiment confirmed that the biomass, seedling height, root length and number of leaves in plants treated with either Class2-1B or Class2-1C were higher than the control group, although not all differences reached the significant level. In contrast, the plant growth was obvious inhibited in the presence of the Class2-3. Under salinity stress, it appeared that most seedlings inoculated with either the Class2-1B or Class2-1C were more salt tolerant, particularly for the Class2-1B treatment, than the control and mixed inoculation groups as evidence by the salt injury index. However, the chlorophyll contents in all treatments did not differ significantly. Conclusion The degree of endophytic Fusarium-mediated plant growth and salt tolerance mainly depends on different Fusarium species. The result of the study, at least in part, demonstrates that the positive or negative effect of endophytic Fusarium on plants might be related to the type and content of the toxins they produced.
2018, 31(5): 74-81.
doi: 10.13275/j.cnki.lykxyj.2018.05.010
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Objective To study the effects of temperature and elemental content on annual seasonal dynamic of coarse woody debris (CWD) respiration rate (RCWD) and provide reference for calculating the carbon flux of CWD respiration and the establishment of carbon pool model. Method The RCWD of Pinus massoniana and Lithocarpus glaber were measured using an infrared gas exchange analyzer (Li-Cor8100) and the CWD initial element content. The effect of temperature and element content on RCWD were discussed. Result The dynamics of RCWD were in accordance with the trend of seasonal temperature, which showed a distinct single peak curve pattern. Within the temperature range of 14.5-28.5℃ measured, the RCWD was significant positively correlated with temperature (p < 0.01). The temperature can predict 64.0%-75.6% of P. massoniana RCWD, and 69.3%-86.2% of L. glaber RCWD. The Q10 of P. massoniana (3.05) was significantly lower than that of L. glaber (5.05). The RCWD of P. massoniana was less than that of L. glaber, meanwhile the initial C content of P. massoniana was significantly higher than that of the L. glaber, and the initial N and P content was significantly lower than that of the L. glaber. RCWD was negatively correlated with initial C content, C/N and C/P, and the correlation coefficients R2 were 0.383, 0.590 and 0.546 respectively. RCWD was positively correlated with the initial N content, the correlation coefficient R2 was 0.416. But there was no significant correlation among RCWD, P content and N/P. These indicated that initial element content can explain the 38.3%-59.0% of the RCWD changes. Conclusion The study showes that temperature and initial C/N can explain more than half RCWD changes in what place. Temperature and initial element content significantly affect the whole process of CWD respiration or decomposition.
2018, 31(5): 82-90.
doi: 10.13275/j.cnki.lykxyj.2018.05.011
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Objective To analyze the univariate and bivariate distribution characteristics of DBH and tree height of Larix gmelini natural forest in Huzhong forest zone of Greater Khingan Mountains Region, and to reveal the size distribution of forest fragile zones of forest communities. Method Three sample plots of L. gmelini forest with different species composition (herbage-Larix, Rhododendron-Larix, and Ledum-Larix) were set up in Huzhong Forest Farm, the relationship between the DBH and the tree height was studied by the whole and layered method. Result (1) The DBH distribution of herbage-Larix forest followed a single peak distribution and the other two plots followed a bimodal distribution. The DBH distribution of the three plots was left-biased. The tree height distribution of Rhododendron-Larix forest was multimodal, and the other two plots were unimodal. (2) The DBH distribution of the upper and lower layers of the three plots were all unimodal. The DBH distribution of the upper layer on all the three plots was left-biased, the lower layer of the herbage-Larix forest was right-biased, the Rhododendron-Larix forest was left-biased, and the Ledum-Larix forest was approximately normal. The height distribution of Rhododendron-Larix forest in the upper and lower layers was bimodal, and the other two plots followed single distribution. The height distribution of the upper layers of these plots was the left-biased, while the height distribution of the lower layers of the three plots was right-biased. (3) The percentage of small diameter trees in herbage-Larix forest and Rhododendron-Larix forest was significantly higher than that in the large diameter forest. The ratio of tree height to DBH in small diameter forests was significantly higher than that in large diameter forest. The ratio of small diameter trees in the upper layer of herbage-Larix forest and Rhododendron-Larix forest was larger than that of the large diameter forest, the ratio of large DBH trees in the lower layer of Ledum-Larix forest and Rhododendron-Larix forest was higher than that of small diameter forest. However, no significant difference was found in the ratio of height and DBH between the upper and lower layers of the three plots. Conclusion The average height of the high-density Rhododendron-Larix forest is higher than that of the low-density Ledum-Larix forest and herbage-Larix forest, and the average DBH has no significant difference in different density and different typed forests. The ratio of tree height to DBH in small diameter forest is significantly higher than that in large DBH forest, but the difference is not obvious in upper and lower standings.
2018, 31(5): 91-97.
doi: 10.13275/j.cnki.lykxyj.2018.05.012
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Objective To explore the potential mechanisms of interaction and function between bamboo forest and its understory vegetation's leaf litter, and provide a theoretical reference for the rational management of understory vegetation in Phyllostachys edulis forest. Method The litter in situ decomposition and nutrient release process of Ph. edulis and understory vegetation (Dicranopteris pedata) in Changning of Sichuan Province were investigated using litter bag. Result (1) The initial C, N, P contents and Carbonyl C of D. pedata were higher than those of Ph. edulis (P < 0.05), while C:N, C:P and Alkyl C, O-alkyl C and Aromatic C of D. pedata were all lower than those of P. edulis (P < 0.05). (2) The rate of litter decomposition and nutrient releasing of D. pedata were higher than that of Ph. edulis. The decomposition coefficient of Ph. edulis and D. pedata were 0.58±0.03 and 0.73±0.02, respectively. C, N and P nutrient release all showed net release. (3) The litter mixture of Ph. edulis and D. pedata had no significant effect on the decomposition rate, however, it significantly inhibited the release of N and P elements throughout the decomposition cycle and C elements in the late. (4) The change pattern of element content in litter decomposition process of Ph. edulis and D. pedata showed that C content and C:N ratio turned out a downward trend, and N content and N:P ratio increased slightly. P content showed a slight downward trend, and C:P ratio fluctuated. (5) Litter decomposition rate was positively correlated with soil temperature, initial litter N and P content (P < 0.01), and negatively correlated with C:N and C:P of initial litter (P < 0.01), but had no significant correlation with soil water content. Conclusion There was no significant mixed effect of decomposition rate, but the mixed effect of nutrient release showed certain negative effects and different periodic features.
2018, 31(5): 98-103.
doi: 10.13275/j.cnki.lykxyj.2018.05.013
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Objective The growth and content of active constituents of Tetrastigma hemsleyanum under different light quality treatments were studied to determine the optimum light quality conditions for the growth of T. hemsleyanum. Method Two-year-old T. hemsleyanum was used as the material, and the light quality treatment was carried out with different color filter membranes (red, yellow, green, blue, and white light). The leaf shape index, physiological index, biomass and total flavonoid content in the tuber of T. hemsleyanum were determined. Result The result suggests that the red light treatments do have impact on the growth and active ingredients of T. hemsleyanum. Red light treatment promotes both the growth and active ingredients of T. hemsleyanum while the other treatments promote just one aspect of them. Conclusion The yield and quality of T. hemsleyanum under red light treatment are better. Red light can be used to increase the yield and active ingredient content in the artificial cultivation of T. hemsleyanum.
2018, 31(5): 104-109.
doi: 10.13275/j.cnki.lykxyj.2018.05.014
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Objective To study the responses of age-related leaf morphology, photosynthetic rate, photosynthetic pigments, and leaf nitrogen of Pinus armandii and P. tabuliformis to gap-model thinning, intending to explore the influences of gap size, leaf age, and species on leaf characteristics after thinning. Method The small gaps (80 m2), intermediate gaps (110 m2) and a control were set in a 30-year-old mixed P. tabuliformis and P. armandii plantation in 2008. The P. armandii and P. tabuliformis in control plots and gap-edged pines were chosen as test materials, and the leaf mass per area (LMA), area-based chlorophyll a, chlorophyll b, nitrogen content (N), maximum photosynthetic rate (Amax), and photosynthetic nitrogen use efficiency (PNUE) of current year, one-year-old, and two-year-old leaves were measured in 2013. Result Small and intermediate gaps had no significant influences on current-year leaves of P. armandii and P. tabuliformis, while significantly altered chlorophyll, N content, and PNUE, enhanced Amax of one-year-old and two-year-old leaves. P. armandii had lower LMA, chlorophyll content, N, and Amax. Moreover, older leaves of P. armandii and P. tabuliformis showed differentiated responses to gap-model thinning:gap-edged P. armandii showed lower chlorophyll content, higher Amax and PNUE than the control, while the LMA and N were no significantly different with the control; gap-edged P. tabuliformis had higher Amax and N than the control, while LMA and PNUE had no obvious difference with the control. Conclusion Gaps in size of 80-110m2 can alter the leaf characteristics and improve its photosynthetic capacity. Gap-model thinning has significant influences on the older leaves, while has no influence on current leaves. P. armandii and P. tabuliformis have different responding strategies to gap-model thinning.
2018, 31(5): 110-117.
doi: 10.13275/j.cnki.lykxyj.2018.05.015
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Objective To study the dust-retention ability, spatial distribution characteristics and the relevance with meteorological and PM10 condition in three kinds of road protection forests (Pinus tabulaeformis forest, Sabina chinensis forest and Ginkgo biloba forest). Method The dust-retention amount was determined by gravimetric method and using dust-retention amount per unit dry weight (mg·g-1) to express the leaf dust-retention capacity. From winter to autumn, the three kinds of road protection forests were observed continuously from different distance of the road, and the dust retention ability of these road protection forests was compared. The relevance between dust-retention effect and rainfall, wind speed, relative humidity, PM10 and spatial distribution characteristics of dust retention of three kinds of road protection forests was analyzed too. Result (1) The dust retention ability among the three tree species was S.chinensis > G. biloba > P. tabulaeformis, which were 4.20±0.19 mg·g-1, 1.98±0.07 mg·g-1, 1.71±0.07 mg·g-1, respectively. The dust amount of P. tabulaeformis and S. chinensis forest showed a characteristic of winter > spring > autumn > summer; there was no significant difference in the dust amount of G. biloba between spring and autumn, and summer was the lowest season; the dust-retention ability of 3 kinds of road protection forests in four seasons all showed S.chinensis > G.biloba > P. tabulaeformis. (2) The spatial distribution of the 3 kinds of road protection forests are as follows:the spatial distribution of dust in P. tabulaeformis and S. chinensis forest was "high at both ends and low in the middle", and the middle position of G. biloba forest was slightly higher than the both sides. The spatial distribution of different seasons showed that:north side was higher in winter, south side was higher in spring, and no significant differences in the north and south sides in spring and autumn. (3) The precipitation was the most negative factor to dust-retention, while the wind speed, temperature, relative humidity and PM10 had positive direct effect to dust-retention. Conclusion Under the same configuration mode (5 m×5 m) and stand age (18 years), Pinus tabulaeformis forest had the largest dust-retention ability, followed with Sabina vulgaris and Ginkgo biloba forest. Winward side always had more dust-retention amount, so configuration of winward trees should be optimized. Precipitation was the most nagative factor to dust-retention, and in winter and spring, which caused more dust-retention amount in winter and spring forest, and artificial rinsing measures could be taken to exert more dust-retention effect.
2018, 31(5): 118-124.
doi: 10.13275/j.cnki.lykxyj.2018.05.016
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Objective To obtain proper sample size for determining the genetic structure of a population of black locust gall midge Obolodiplosis robiniae (Haldemann) (Diptera, Cecidomyiidae). Method The sample sizes with 12 gradients and 11 polymorphic microsatellite loci were used to assess five O. robiniae populations. Result The results revealed that the sample size took significantly positive correlation with the number of alleles per locus (Na), and moderately positive correlation with the effective number of alleles per locus (Ne), but had moderately negative correlation with observed heterozygosity, however little influence was found on the expected heterozygosity, Nei's genetic diversity and polymorphism information content. When the sample size < 25, the number of alleles per locus increased rapidly and observed heterozygosity greatly changed, but they changed gently when the sample size>30. Conclusion Concerning the genetic diversity analysis for populations of O. robiniae with microsatellite DNA markers, the optimum sample size appears to be 25~30, and the optimum parameters are the expected heterozygosity, Nei's genetic diversity and polymorphism information content. The results of this study are helpful to microsatellite marker-based analyses of the genetic structure of populations of other invasive dipteran pests.
2018, 31(5): 125-130.
doi: 10.13275/j.cnki.lykxyj.2018.05.017
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Objective Microsatellite markers were used to compare the genetic diversity and genetic structure of Rhododendron simsii populations at four different life stages sampled from Huangshizhai of Dabieshan region to clarify the mechanism of genetic diversity among different age groups. Method The populations of R. simsii were divided into four age groups (old trees, adult, juvenile, and seedlings) according to their sizes of basal diameter and numbers of branches. Twelve SSR markers were used for PCR amplification, and the products were subjected to 6% polyacrylamide gel electrophoresis, which were further visualized through silver staining. The "0/1" matrix was constructed and POPGENE 32.0 software was used to analyze the genetic diversity. Based on Nei's genetic distance, UPGMA dendrogram was constructed with MEGA 5.0 software. Result Different genetic diversities were observed in the four R. simsii populations, the lowest genetic diversity was observed in seedlings population, followed by old trees population, while the highest genetic diversity was observed in juvenile population. The observed and effective number of alleles per locus ranged from 3 to 9 and 2.254 9-6.129 7, with the average of 5.08 and 3.460 5, respectively. Moreover, HO and HE were in the ranges of 0.676 4-0.881 2 and 0.607 7-0.690 7, respectively. The Shannon's information index (I) was the highest in juvenile population, followed by adult population, and lowest in seedling population. Fis and Fit ranged within-0.638 3-0.174 4 and-0.615 1-0.270 6, with the mean of-0.294 6 and-0.162 1, indicating the outcross took place frequently. In particular, the AMOVA analysis showed that 89.76% of genetic variation was maintained within age groups, while only 10.24% presented among age groups. Frequent gene flow was observed, as only one locus showed Nm less than 1.0.The genetic identify between adult and juvenile groups was the highest. Conclusion High genetic diversity existed among R. simsii populations located on Huangshizhai. Moderate differentiation was observed, which was maintained between age groups.
2018, 31(5): 131-136.
doi: 10.13275/j.cnki.lykxyj.2018.05.018
Abstract:
Objective Cephalostachyum pingbianense is an excellent edible bamboo species endemic to southern Yunnan Province of China. So far, C. pingbianense is the only bamboo species recorded as producing shoots in all year under natural conditions. The purpose of this study is to investigate the biological characteristics of shooting and the growth pattern of young bamboos. Method The data of bamboo shooting number, degraded shoot number, culm height, diameters of shoot and young culms were collected from 30 clumps of C. pingbianense, and analyzed using SPSS software. Result (1) The shooting duration of C. pingbianense lasted for about 9 months (from September to next May). According to the quantity of bamboo shoots, the shooting duration could be divided into three stages, i.e., the early stage, the peak stage and late stage. The most shoots occurred in winter while the least occurred in summer. Five clumps (16.67%) produced bamboo shoots in each season, displaying the characteristics of producing bamboo shoot in all the four seasons. (2) The percentage of the degraded shoot increased gradually during the shooting period, and reached the maximum (87.76%) at the late stage. (3) The height growth of young bamboo culms lasted about 130 days, with an average height of 6.36 m. A growth pattern of "slow-fast-slow" was found at the period of the height growth of young bamboo culms, and the growth curve could be described with an equation:H=0.806-0.029t+0.001t2-5.894×10-6t3 (R2=0.980). (4) The diameter growth of young culms at the ground lasted about 16 days, with an average diameter of 18.50 mm. The diameter growth of young culms also accorded with the pattern of "slow-fast-slow". Conclusion C. pingbianense could produce bamboo shoot all the year round, with a 9 months shooting period, however, the shoot quantity in each season is different significantly. The culm height and culm diameter at the ground accorded with a pattern of "slow-fast-slow".
2018, 31(5): 137-144.
doi: 10.13275/j.cnki.lykxyj.2018.05.019
Abstract:
Objective To investigate the effects of fertilizer rate and irrigation method on morphological attributes, nutrient status, medium electrical conductivity (EC) and 2-years' outplanting performance of containerized Quercus variabilis seedlings. Method Seedlings were raised with 5 fertilizer rates (25, 75, 125, 175, and 225 mg·plant-1) and 2 irrigation methods (overhead irrigation (O) and subirrigation (S)). The experiment was a two-factor completely randomize design. Morphological attributes, nutrient status, root growth, medium EC, and 2-years' outplanting performance were measured. Result Interaction of fertilizer rate and irrigation method significantly affected seedling growth. The root-collar diameter, root and total biomass of seedling reached maximum value with 225-O treatment. There was no significant difference on root and total plant biomass among 225-O, 125-S, and 175-O. The height, stem biomass, and S/R ratio of seedling reached maximum value with 225-S treatment. There was no significant difference on stem biomass among 225-S and 225-O. The nutrient concentration and content were improved with increasing fertilizer rate. There was no significant difference on root N, P content and total P content among 125, 175, and 225 mg·plant-1. Increasing fertilizer rate promoted root growth. There was no significant difference on root surface area and volume among 125, 175, and 225 mg·plant-1. Fertilization resulted in high medium EC. Subirrigation significantly increased medium EC in upper and bottom layer. The highest medium EC reached 4.69 dS·m-1 but did not have harmful effect on seedlings. Subirrigation improved the height and root-collar diameter of seedlings 1 year after outplanting. 2 years after outplanting, the height and root-collar diameter of seedlings grew greatly with increasing fertilizer rate, but there was no significant difference on height and root-collar diameter of seedlings among 125, 175, and 225 mg·plant-1. Conclusion Subirrigation improves nutrient content and 1-year's outplanting performance. Controlled-release fertilizer increased seedlings quality, and 2-years' outplanting performance. Considering seedling quality, economic benefits and environmental value, fertilizer rate of 125 mg·plant-1 and subirrigation was the optimum combination for container seedling production of this species.
2018, 31(5): 145-152.
doi: 10.13275/j.cnki.lykxyj.2018.05.020
Abstract:
Objective To find out the indication roles of Odonata aquatic insects in Dianchi Lake riparian wetland water quality evaluation. Method The physicochemical variables were measured and Odonata aquatic insect community structure was surveyed at 12 sites in Haidongwan riparian wetland, the entrance of Dianchi Lake. The water quality levels were classified; The IndVals and community feature indices were calculated and compared. The correlation between the aquatic insect community structure, the physicochemical variables and water quality levels; the aquatic insect community structure and the physicochemical variables were analyzed by Pearson correlation analysis. Result The species composition of aquatic insects at different water quality levels was different. Megalestes was the indicator of level Ⅱ. Copera and Ischnura were the indicators of level Ⅲ. There are no indicators of level Ⅳ and Ⅴ. For the community feature indices, Simpson dominance index and Shannon-Wiener diversity index decreased with the decrease of water quality levels. The water quality levels were positively correlated with total phosphorus and chemical oxygen demand, and negatively correlated with dissolved oxygen. Moreover, the Simpson dominance index, Shannon-Wiener diversity index of Odonata aquatic insects showed significant positive correlation with dissolved oxygen, and significant negative correlation with the total phosphorus. Conclusion Odonata aquatic insect species and community structure characteristics can be used to indicate the water quality of Haidongwan wetland water quality so as to indirectly reflect the water quality of Dianchi Lake.
2018, 31(5): 153-158.
doi: 10.13275/j.cnki.lykxyj.2018.05.021
Abstract:
Objective To explore the effects of twig ages on the formation of the adventitious roots from the upper and lower branches in the crowns of Ginkgo biloba, and discuss the relationship between rooting and non-structural carbohydrates (NSC) in the corresponding leaves and stems. Method Experimental materials with the cutting of one-, two-, and three-year-old twigs were investigated from the upper and the lower parts of the crown, and the NSC contents were analyzed by the HLPC in the leaves and stems of the corresponding positions. All cuttings were treated with 0 and 500 mg·L-1 IBA under natural light and spraying management. Result The process of the adventitious root formation includes four stages:callus formation (0-4 weeks), callus expansion (4-6 weeks), initiation of adventitious root (6-8 weeks) and root elongation (after 8 weeks). No significant difference was observed in the rooting of cutting between the twigs from the upper and the lower branches of crowns, while it was considerably inhibited by the ages of twigs. The NSC analysis showed that the contents of polysaccharides and total sugars in the leaves from the lower crown were higher than the upper one, but all the NSC components tested showed no significant differences between the twigs from these two parts. However, the NSF contents had no significant changes in the corresponding leaves, whereas they decreased significantly in the corresponding stem fragments with the increasing ages of twigs, including glucose, fructose, polysaccharides, total sugars and starch, which showed the similar trends with the rooting changes. Besides, the treatment of 500 mg·L-1 IBA didn't improve the rooting rate compared to the control, and this needed to be further optimized. Conclusion The position of the upper and lower branches has no significant effect on the formation of adventitious roots in the crowns of G. biloba. The age of untreated twigs was negatively correlated with rooting, but stem NSC content was positively correlated with rooting; the induced callus rooting is the main type for the cutting of G. biloba. This result will provide the references for the future study of cutting process and its mechanism in G. biloba.
2018, 31(5): 159-167.
doi: 10.13275/j.cnki.lykxyj.2018.05.022
Abstract:
The purpose of this study is to review the nematode species parasitizing on bamboos, their distribution and hosts. 82 nematode species belonging to 29 genera and 12 families of 4 orders were reported on bamboo in the world, in which 36 species in China, 38 species in American, and 20 species in India. Few studies focus on the pathogenicity of plant nematodes to bamboos. There were some reports of nematodes causing losses on bamboos in India. Histological observations of two nematode species in infected bamboos were reported in USA. This paper discusses the research direction of nematodes parasitizing on bamboo, aiming at providing useful information for research, control and quarantine of nematodes parasitizing on bamboo.
The purpose of this study is to review the nematode species parasitizing on bamboos, their distribution and hosts. 82 nematode species belonging to 29 genera and 12 families of 4 orders were reported on bamboo in the world, in which 36 species in China, 38 species in American, and 20 species in India. Few studies focus on the pathogenicity of plant nematodes to bamboos. There were some reports of nematodes causing losses on bamboos in India. Histological observations of two nematode species in infected bamboos were reported in USA. This paper discusses the research direction of nematodes parasitizing on bamboo, aiming at providing useful information for research, control and quarantine of nematodes parasitizing on bamboo.
2018, 31(5): 168-175.
doi: 10.13275/j.cnki.lykxyj.2018.05.023
Abstract:
Objective To provide reference for the follow-up family selection and variety extension by genetic variation analysis and stability evaluation of the growth traits of Litsea cubeba families. Method 13 L. cubeba families were used to establish pedigree test forests in Wanzhou of Chongqing Municipality, Jingshan of Hubei Province and Qingliu of Fujian Province, which were designed in randomized complete blocks. The height and ground diameter were measured and analyzed when the forests were 2-years-old, then the growth performance and stability of different L. cubeba families were evaluated by AMMI model. Result (1) Both the family and site effect of height and ground diameter were significant(0.01 < P < 0.05) or highly significant (P < 0.01), the interaction effect of family and site of ground diameter was significant (0.01 < P < 0.05); the phenotypic variance coefficient of height and ground diameter ranged from 20.98% to 29.27%; the genetic variation coefficient of which ranged from 0.62% to 20.35%; and both the phenotypic and genetic variance coefficient of ground diameter were generally larger than that of height; the family heritability of tree height ranged from 0.003 to 0.578, and the family heritability of ground diameter ranged from 0.455 to 0.806. (2) Both the families JY2 and GX4 performed well in ground diameter and stability. Conclusion The family and site effect of height and ground diameter are both significant(0.01 < P < 0.05) or highly significant (P < 0.01), there is rich genetic variation. In the family level, the height of tree is genetically controlled by low to medium intensity, and the ground diameter is genetically controlled by medium to high intensity. The growth of different families performs best in Qingliu, followed by Jingshan, and the worst in Wanzhou. The families JY2 and GX4 show good ground diameter performance and high stability.
2018, 31(5): 176-184.
doi: 10.13275/j.cnki.lykxyj.2018.05.024
Abstract:
Objective To explore the ectomycorrhizae types and relationship with forest stands at Leigong Mountain Nature Reserve, and to study the ectomycorrhizae in four preponderant forest stands. Method The methods of random sampling and rDNA ITS sequencing were applied in this study. Result The results showed that seven types of genus Tomentella were determined by phenotype with brown morphotypes that was similar with genus Tomentella, and the results was verified by rDNA ITS sequencing, . Six of them were identified as T. badia, T. fuscocinerea, T. atramentaria, T. lapida, T. ramosissima and T. terrestris, respectively. Conclusion This research is the first report that the genus Tomentella was found at Leigong Mountain Nature Reserve, so the results will benefit for next research at commensalism and function with four preponderant forest stands at Leigong Mountain Nature Reserve.
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