2023 Vol. 36, No. 5
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2023, 36(5): 0-0.
Abstract:
2023, 36(5): 1-11.
doi: 10.12403/j.1001-1498.20230069
Abstract:
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.
2023, 36(5): 12-20.
doi: 10.12403/j.1001-1498.20230050
Abstract:
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.
2023, 36(5): 21-31.
doi: 10.12403/j.1001-1498.20230024
Abstract:
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.
2023, 36(5): 32-40.
doi: 10.12403/j.1001-1498.20220542
Abstract:
Objective To explore the nitrogen release and conservation capacity of forest soil under different cutting methods, and reveal the impact of cutting methods on forest soil N nutrient cycle. Method A laboratory incubation experiment was conducted to study the effects of selective cutting and clear cutting on gross and net N transformation rates in broad-leaved mixed forest soil in cold temperate zone, using 15N paired isotope labeling technique and FLUAZ numeric model. Result In the reserved belt without any cutting, soil gross N mineralization, net N mineralization, gross N immobilization, gross nitrification, and net nitrification rates were 4.16, 1.86, 2.32, 0.368, and 0.343 mg∙kg−1∙d−1, respectively. In comparison with the treatment of reserved belt, soil gross N mineralization rates of the selective cutting and clear cutting treatments significantly decreased by 32.2% and 61.8%, respectively, soil net N mineralization rates significantly decreased by 43.1% and 61.5%, respectively, and soil gross N immobilization rates significantly decreased by 23.3% and 63.4%. Selective cutting had no significant effects on gross and net nitrification rates in soil, while clear cutting significantly decreased soil gross and net nitrification rates by 23.6% and 33.3%, respectively. The correlation analysis indicated that soil organic C and water soluble organic C were the main factors influencing gross and net N mineralization and immobilization rates in soil, and pH was the main factor influencing gross and net nitrification rates in soil. Conclusion Our results indicate that the decrease of gross ammonium immobilization rate is greater than that of gross nitrification rate after clear cutting, leading to the significant increase of ratio of gn/ia and NO3−/NH4+ in soil, which increases the risk of NO3− leaching. However, the ratio of gn/ia and NO3−/NH4+ in soil under selective cutting is not significantly different from that of the reserved belt, which is a desirable way of forest harvesting.
2023, 36(5): 41-49.
doi: 10.12403/j.1001-1498.20230072
Abstract:
Objective To explore the driving factors of the dynamic processes of aboveground biomass of mixed forests in Northeast China for accurately understanding the forest services and functions. Methods Based on 110 fixed plots in Jingouling Forest Farm in Northeast China, forest dynamics processes from 1987 to 2017 were described. Piecewise structural equation models were used to assess the impact of forest structure, climate, topography and diversity on the dynamic processes (growth, recruitment and mortality) of biomass, and the effects of dynamic processes on stability were further explored. Result The results showed that the growth of biomass was positively affected by stand basal area (β=0.562), altitude(β=0.853), and mean annual temperature (β=0.820), and negatively correlated with the Gini coefficient of diameter at breast height (β=−0.274). The increment of tree recruitment was positively associated with altitude (β=0.913), mean annual temperature (β=0.944), and negatively related to the coefficient of variation of diameter at breast height (β=−0.233). The biomass loss was only significantly positively correlated with the stand basal area (β=0.467). In addition, this study also found that mortality was the most important factor affecting the biomass stability. Conclusion In general, altitude and MAT plays an important role in the biomass change. We should pay more attention to the situation of dead trees in the future for forest management.
2023, 36(5): 50-59.
doi: 10.12403/j.1001-1498.20220501
Abstract:
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 stage (1.45 ± 0.22), followed by blossom stage (1.25 ± 0.13), leaf unfolding stage (0.98 ± 0.05) and defoliation stage (0.95 ± 0.14) was the smallest, and the average of the whole growth stage was 1.28 ± 0.16. There was a significant positive correlation between crop coefficient and LAI (p < 0.01), with the coefficient of determination R 2 0.736, and there was no significant correlation between crop coefficient and growth of new shoot length (p > 0.05).
2023, 36(5): 60-71.
doi: 10.12403/j.1001-1498.20220545
Abstract:
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.
2023, 36(5): 72-82.
doi: 10.12403/j.1001-1498.20220608
Abstract:
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.
2023, 36(5): 83-90.
doi: 10.12403/j.1001-1498.20220604
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Objective This study aimed 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 normal conditions, the transgenic plants and the WT showed little change in growth traits, chlorophyll content, catalase (CAT), malondialdehyde (MDA) and peroxide dismutase (POD) content. 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.
2023, 36(5): 91-99.
doi: 10.12403/j.1001-1498.20220541
Abstract:
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.
2023, 36(5): 100-110.
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.
2023, 36(5): 111-120.
doi: 10.12403/j.1001-1498.20230077
Abstract:
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. Compared with the drought treatment, (1) 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.
2023, 36(5): 121-130.
doi: 10.12403/j.1001-1498.20220560
Abstract:
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.
2023, 36(5): 131-139.
doi: 10.12403/j.1001-1498.20220603
Abstract:
Objective To study the model uncertainty induced by different types of variables on carbon storage estimation. Method Taking as the research object, Random forest joint Monte Carlo (RF-MC) was used to establish a carbon storage regression model of Shangri-La Pinus densata based on different variable combinations to determine the uncertainty of each model. Result (1) Spectral and plot data directly contributed to the estimation accuracy and uncertainty of the RF-MC model. (2) The model prediction introducing texture features was better than introducing DEM. (3) The RF-MC model that introduced both DEM and texture features performed the best (R2=0.892, RMSE=5.539 t·hm−², MAE = 4.319 t·hm−², rRMSE=18.7%). The model fit improved by 0.343 and the uncertainty of the model decreased by 19.43%. Conclusion The RF-MC method based on multiple characteristics performs well on carbon storage estimation. Different types of variables have certain impact on the accuracy and uncertainty of carbon storage estimation.
2023, 36(5): 140-148.
doi: 10.12403/j.1001-1498.20220420
Abstract:
Objective To achieve the rapid and effective differentiation 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 the 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−1 and 60 fg·μL−1. Conclusion Through establishing a visual LAMP-HNB detection system, M. medusae and M. larici-populina can be differentiated and identified by the LAMP technology. This study provides a technological support in practice for rapid identification and detection of the important poplar rust diseases.
2023, 36(5): 149-159.
doi: 10.12403/j.1001-1498.20220543
Abstract:
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.
2023, 36(5): 160-168.
doi: 10.12403/j.1001-1498.20230126
Abstract:
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.
2023, 36(5): 169-179.
doi: 10.12403/j.1001-1498.20220585
Abstract:
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 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.
2023, 36(5): 180-188.
doi: 10.12403/j.1001-1498.20230122
Abstract:
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.
2023, 36(5): 189-197.
doi: 10.12403/j.1001-1498.20230134
Abstract:
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.
2023, 36(5): 198-204.
doi: 10.12403/j.1001-1498.20220565
Abstract:
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.
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