2019 Vol. 32, No. 6
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2019, 32(6): 1-6.
doi: 10.13275/j.cnki.lykxyj.2019.06.001
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Abstract:
Objective To explore the correlation between leaf moisture and leaf hyperspectral reflectance characteristics among walnut (Juglans regia L.) varieties and the differences among varieties. Method The leaves of five walnut varieties were selected as the test materials, the leaf moisture and hyperspectral reflectance during the dehydration process were measured, and the correlation between leaf moisture and hyperspectral reflectance were analyzed. The differences in the water sensitive bands among walnut varieties were compared. Result (1) The leaf constituents and the leaf structure among walnut varieties were similar, and only the differences in chlorophyll and moisture content were observed; (2) The correlation between leaf moisture and reflectance among walnut varieties was significant (p < 0.05) in 621-703 nm and 1 244-2 500 nm, and was not affected by moisture indicators; (3) The leaf reflectance showed obvious differences among walnut varieties, and had different water-sensitive bands in 704-1 243 nm. Conclusion The differences in the correlation between water content and hyperspectral reflectance of leaves are significant among walnut varieties in the range of 704-1 243 nm.
2019, 32(6): 7-13.
doi: 10.13275/j.cnki.lykxyj.2019.06.002
Abstract:
Objective To investigate the effects of irrigation and nitrogen application on soil nitrate accumulation and distribution, so as to provide visions for specific irrigation and fertilization management principles and guidelines as well as reducing nitrate leaching in intensively managed Populus tomentosa var. tomentosa industrial plantation. Method The study site locates in Weixian County of Hebei Province where a long-term irrigation and fertilization supported by "12th Five-Year Plan" research project has been initiated with aims to improve timber production. By maintaining the soil water content above different field water holding capacity (45%, 60%, 75%) and different nitrogen application rate (0.0, 101.6, 203.2, and 304.8 kg·hm-2), the distribution pattern and accumulation of soil nitrate were studied. Result Soil nitrate content had an obvious surface accumulation tendency. From 0-200 cm, the soil nitrate content followed a S-shaped pattern (decrease-increase-decrease). The higher rate the nitrogen, the more the accumulation of nitrate in the soil layer between 60-100 cm. With the increase of soil moisture level, the leaching peak of soil nitrate was going down to 40-60, 60-80, and 80-100 cm, respectively. The nitrate accumulation in soil increased with the increase of nitrogen application rate. With the increase of soil moisture level, the soil nitrate showed an up then down pattern. Meanwhile, the water and nitrogen had a significant positive interaction on the distribution and accumulation of nitrate. In this study, different combinations of water and nitrogen of the soil nitrate accumulation ranged from 86.11-259.29 kg·hm-2. Conclusion Nitrogen application and soil moisture levels have significant effects on the distribution and accumulation of soil nitrate in the P. tomentosa var. tomentosa stand. With the increase of nitrogen application rate, the soil nitrate shows a tendency to build up in the soil layer between 0-200 cm. With the increase of irrigation level, the soil nitrate accumulation peak tends to move downward gradually. Compared with the farmland ecosystem, the accumulation of nitrate between 0-200 cm in the forest ecosystem is lower. This indicates that in evaluation of soil nitrate distribution and accumulation, consideration should be given to the deep root system of the forest ecosystem. While, in order to reduce the leaching of nitrate nitrogen, it is recommended to reduce the application of nitrogen fertilizer and control the field water holding capacity between 60% and 75%.
2019, 32(6): 14-20.
doi: 10.13275/j.cnki.lykxyj.2019.06.003
Abstract:
Objective In order to verify the function of FAD gene of Kerria chinensis, the RNAi system by bacterial expression of dsRNA was used and the function of FAD gene was preliminarily analyzed to provide references for verifying the function of genes related to lac synthesis. Method The FAD gene of K. chinensis and L4440 vector were digested by double enzymes primarily, then the FAD-L4440 recombinant plasmid was constructed by T4 ligase ligation and transferred into HT115 competent cells as well. After the expression of dsRNA induced by IPTG, the dsRNA was transfected into lac insect by spreading it to the trunks. Detected the FAD gene expression after RNAi by RT-qPCR and the amount of individual lac secreted was also measured timely. Result The expression of FAD gene significantly decreased. There was a significant difference between the control group and the low concentration bacterial solution treated for 12 hours and the medium concentration bacterial solution treated for 12 hours, which decreased by 90.79% and 85.46% respectively. The interference efficiency of medium concentration at 72 hours was higher than that of the other two groups and there was a significant difference in the amount of individual lac secretion in comparison with the control group. Conclusion In this study, the RNAi vectors of FAD gene of K. chinensis were successfully constructed. In the verification of gene function, the RNAi system was used for bacterial expression of dsRNA. The expression of FAD gene and the amount of individual lac secretion decreased significantly after imported into the insect body. It provides a new technical reference for insects which not suitable for injection and feeding for RNAi transfection and it also provides a technical and scientific basis for the verification of molecular mechanism related to lac biosynthesis.
2019, 32(6): 21-30.
doi: 10.13275/j.cnki.lykxyj.2019.06.004
Abstract:
Objective To survey the diseases caused by Phytophthora in wild apple forests in Xinyuan county and Gongliu county of Xinjiang Uygur Autonomous Region aiming at isolating and identifying Phytophthora species, evaluating the pathogenicity of these species, and providing information for finding out the causes of the decline of wild apple forest. Method Phytophthora species were surveyed by the method of collecting samples of suspected Phytophthora diseases, baiting techniques from streams and soils in the wild apple forest in Xinyuan county and Gongliu county on the north slope of the Tianshan Mountains in Xinjiang. The pure isolates of Phytophthora spp. were obtained through selective medium and subculturing. Then these isolates were classified and identified by morphological observation combined with rDNA-ITS sequence analysis, and the pathogenicity of the identified Phytophthora species was determined by in vitro leaf inoculation test. Result Based on morphological characteristics and sequence analysis, a total of 88 Phytophthora isolates were identified from five species, including 65 isolates of Phytophthora lacustris Brasier, Cacciola, Nechwatal, Jung & Bakonyi, 16 isolates of Phytophthora gonapodyides (Petersen) Buisman, 3 isolates of Phytophthora plurivora T. Jung & T. I. Burgess, 2 isolates of Phytophthora gregata T. Jung, M. J. C. Stukely & T. I. Burgess and 2 isolates of Phytophthora sp. 1.The former four known Phytophthora species inoculated on the leaves of wild apples were found to produce lesions except for the control, and the most obvious symptoms were formed with the isolate of P. lacustris on the leaves. Conclusion The relatively richness of Phytophthora species were examined in Xinjing wild apple forest. And visible lesions on inoculated wild apple leaves were formed with four Phytophthora species, indicating their definite pathogenicity.
2019, 32(6): 31-39.
doi: 10.13275/j.cnki.lykxyj.2019.06.005
Abstract:
Objective To quantitatively analyze the seasonal change of leaf mass per area (LMA) along canopy height for different aged moso bamboo (Phyllostachys edulis) in natural and drought stress growth environment, and to clarify the response characteristics of LMA to the throughfall exclusion for drought stress, aiming at providing references for sustainable and efficient management of Ph. edulis plantations under the global climate background. Method The spatial and temporal dynamic change of LMA is detected for moso bamboo under two different treatments with rain shelter or not. Result (1) Regardless of throughfall exclusion or not, the LMA increased with the age of bamboo during different growing seasons, and the seasonal change trend from maximum to minimum was spring, winter, autumn and then summer in turn. There were significant differences of LMA among different seasons and treatments for the same age of bamboo (P < 0.05), regardless of throughfall exclusion or not. (2) Regardless of throughfall exclusion or not, the differences of LMA were not significant among canopy for various ages of bamboo, while it was significant among seasons within the same canopy. In natural growth condition, the LMA of each season increased along with the canopy height and its vertical change showed the trend of the upper canopy > middle canopy > lower canopy successively, and the value of each canopy decreased at first and then increased as the growing season. There was significant difference among different seasons (P < 0.01) for LMA of different ages of bamboo, while there was no significant difference among different canopy layers under throughfall exclusion. (3) Under the drought stress, the annual average value and each individual value of the LMA were all higher than the control in every season. The drought stress relieved seasonal difference of LMA in various canopy. The seasonal change of the LMA within the same canopy was also affected by age of bamboo. (4) With or without drought stress, there was linear positive correlation between the LMA and soil water content in each season, but the correlation under drought stress was lower than that of the control. The positive correlation between LMA and ages of bamboo under drought stress was higher than that of the control. Conclusion It is concluded that moso bamboo belongs to the species with lower LMA, and the growth season has significant effect on the change of LMA. Compared with the light, the soil moisture condition has more important influence on the LMA of the moso bamboo.
2019, 32(6): 40-47.
doi: 10.13275/j.cnki.lykxyj.2019.06.006
Abstract:
Objective To explore the effects of different thinning intensity on tree growth and identify the key soil factors affecting forest growth. Method Twelve thinning test plots and control plots were set up in the Larix principis-rupprechtii plantation with mild (thinning intensity 15%), moderate (thinning intensity 35%), severe (thinning intensity 50%) thinning in Haodifang Forest Farm in Qinyuan County, Shanxi Province, and take the average DBH, average tree height, average branch height, average crown width, tree layer biomass and productivity as the tree growth indicators. Variance analysis and multiple comparisons were used to analyze the growth characteristics in the stands with different thinning intensities, and were combined with soil factor to study the relationship between forest growth and soil factors by utilizing correlation analysis. Result The tree-growth index of the L. principis-rupprechtii plantation significantly increased compared with the control after two and four years of moderate and severe thinning. Thinning significantly increased the productivity of the arbor layer while reduced the biomass of the arbor layer in the stand. The productivity of arbor layer in all the period and thinning intensities followed the pattern of severe thinning > moderate thinning > mild thinning > the control. Thinning increased the content of soil organic carbon (SOC), soil total nitrogen (TN) and soil total phosphorus (TP), and reduced the loss of soil nutrients. The average DBH growth of L. principis-rupprechtii plantation was significantly positively correlated with SOC and TN. The average crown growth was significantly positively correlated with soil water content, SOC, TN and TP. Conclusion Thinning can promote the growth of DBH and crown width of individual trees in L. principis-rupprechtii plantation and increase the ratio of crown to diameter and productivity of individual trees. Among the three thinning intensities, the severe thinning intensity is the optimal. Soil organic carbon and soil total nitrogen content in L. principis-rupprechtii plantations are abundant, the soil total phosphorus content is less, and the soil pH is weakly acidic. SOC, TN, TP are crucial factors affecting the growth of L. principis-rupprechtii plantation.
2019, 32(6): 48-55.
doi: 10.13275/j.cnki.lykxyj.2019.06.007
Abstract:
Objective To study the succession trend, natural regeneration and biodiversity in Pinus massoniana plantation in center Hubei. Method The light transmittance and tree regeneration in 4 age classes (9 years-old, 18 years-old, 28 years-old and 48 years-old) and 3 density levels (1 0882 644 trees per hectare) of P. massoniana plantation were investigated. The succession trend and the influence factors of diversity were analyzed. Result The main succession species in P. massoniana plantation is Cinnamomum camphora (L.) Presl, Ilex chinensis Sims, Cunninghamia lanceolata (Lamb.) Hook., Melia azedarach L. and Quercus glandulifera Bl. The biodiversity index of overstory layer and succession layer in P. massoniana plantation increased with the age class. The light transmittance had a significant influence on diversity in regeneration layer (P < 0.01) and succession layer (P < 0.05). The overstory density was correlated to density of seedlings and young trees (P < 0.05). Conclusion The climax community will be I. chinensis Sims + Cinnamomum camphora (L.) Presl + Q. glandulifera Bl. mixed community. The natural regeneration ability in research area is weak. In some area the administrators could assist the natural regeneration by planting broadleaved tree seedlings.
2019, 32(6): 56-62.
doi: 10.13275/j.cnki.lykxyj.2019.06.008
Abstract:
Objective To further understand the mechanism of nitrogen regulation on root respiration of Juglans regia 'Wen185', the main walnut cultivar in South Xinjiang Basin. Method J. regia 'Wen185' was used as experimental material to study the effect of different nitrogen application levels on the fine root respiration rate and related enzyme activity during the growth and development of walnut. Field fertilizer experiment setting and in vitro root determination method were conducted to analyse the fine root's respiration rate (Q) and glycolytic pathway (EMP), Citric acid cycle Pathway (TCA), pentose phosphate pathway (PPP) respiratory rate and the dynamics of phosphofructokinase (PFK), malate dehydrogenase (MDH) and glucose-6-phosphate dehydrogenase (G-6-PDH) activity, as well as the fine root respiration rate and the correlation between enzyme activity under different nitrogen levels. Result With the changes of post-flowering time, the respiration rate of Q, TCA and PPP generally decreased, while the respiration rate of EMP increased at first and then decreased. The respiratory rates of TCA, EMP and PPP accounted for 40.23%, 33.02% and 20.47% of Q respectively. When the nitrogen level (pure quantity) was N2, the respiration rate of Q and TCA, PPP and EMP, as well as the activity of MDH, G-6-PDH and PFK were significantly higher than that of the other nitrogen application levels(P < 0.05). Conclusion TCA pathway respiratory rate occupies a higher proportion in the basic respiratory rate than EMP and PPP pathway. Proper application of nitrogen application levels could improve MDH and PFK activity, and promote root respiration of walnut, and be beneficial to the growth of walnut. Extremely low and high nitrogen application would inhibit root respiration rate and even adversely affect the growth of walnut.
2019, 32(6): 63-72.
doi: 10.13275/j.cnki.lykxyj.2019.06.009
Abstract:
Objective To investigate the carbon and nitrogen metabolism of Populus seedlings under different nitrogen levels. Method Populus alba×P. glandulosa seedlings were treated with high (16 mmol/L N), normal (4 mmol/L N) and low (1 mmol/L N) nitrogen levels, respectively. The growth, carbon and nitrogen metabolism of Populus alba×P. glandulosa seedlings under the three nitrogen supply levels were analyzed. Result High nitrogen led to increased net photosynthetic rate, sucrose content in root, starch content and biomass in the leaves, promoted the carbon metabolism in P. alba×P. glandulosa. Meanwhile, the absorption and accumulation of NH4+ and NO3- in the roots, GOGAT activities in the roots and leaves, the amino acid contents and total N contents were elevated under high nitrogen levels compared with that under normal nitrogen supply, which resulted in enhanced nitrogen metabolism in P. alba×P. glandulosa. In contrast, low nitrogen treatment brought about reduced net photosynthetic rate and the contents of most soluble sugars and starch in leaves, inhibited the carbon metabolism in P. alba×P. glandulosa. Additionally, low nitrogen supply also induced the decreases of NH4+ and NO3- contents in the roots and leaves, decreased the nitrate reductase activities in the roots, and the contents of amino acid and total N in the roots and leaves, leading to inhibited nitrogen metabolism in P. alba×P. glandulosa. Conclusion The carbon metabolism of P. alba×P. glandulosa is highly linked with nitrogen metabolism in response to changing nitrogen levels in the environments. Carbon and nitrogen metabolism is enhanced when nitrogen supply is abundant, and both are inhibited under nitrogen deficiency condition.
2019, 32(6): 73-79.
doi: 10.13275/j.cnki.lykxyj.2019.06.010
Abstract:
Objective To examines the effects of cultivar and dioecy on stoichiometry of Torreya grandis, and provide references for the management of T. grandis stands. Method 300-years-old female (T. grandis cv. 'Dielsii' and T. grandis cv. 'Merrilli') and male T. grandis in T. grandis National Forest Park located in Zhuji of Zhejiang Province were used as test materials. The plant and soil samples were collected from the field to analyze the C, N, P contents and their stoichiometric characteristics. Result (1) There was no significant difference in C, N, P contents and stoichiometric characteristics between T. grandis cv. 'Dielsii' and male T. grandis. Dioecy had no significant effects on the stoichiometry of T. grandis. (2) The contents of C, N, P and their stoichiometric characteristics of T. grandis cv. 'Merrilli' were significantly different from T. grandis cv. 'Dielsii' and male T. grandis. Among them, the C content in T. grandis cv. 'Merrilli' leaves (533.0 g·kg-1) was significantly higher than that in T. grandis cv. 'Dielsii' (502.8 g·kg-1) and male T. grandis (502.7 g·kg-1), and the P content in T. grandis cv. 'Dielsii' roots (1.5 g·kg-1) was significantly higher than that in T. grandis cv. 'Dielsii' (0.9 g·kg-1) and male T. grandis (0.9 g·kg-1). Generally, the C:N ratio of T. grandis cv. 'Merrilli' was higher than that of T. grandis cv. 'Dielsii' and male T. grandis, while the C:P and N:P ratios were lower. (3) The contents of C, N and P in different organs of T. grandis exhibited the same trend. The content of C and P displayed in the order of leaves > branches > roots, leaves were the highest, and the content of C in root and the content of P in branch were the lowest. And N content of leaves were significantly higher than of roots and branches. The C:N and C:P ratios of different organs of T. grandis cv. 'Dielsii' and male T. grandis were roots > branches > leaves, and the N:P ratio was roots > leaves > branches. The C:N ratio of T. grandis cv. 'Merrilli' was branches > roots > leaves, the C:P ratio was roots > branches > leaves, and the N:P was leaves> roots > branches. Conclusion Dioecy of T. grandis shows no significant effect on the stoichiometric characteristics of tree, so it can be ignored during the management. The stoichiometric characteristics of T. grandis is significantly affected by management measures.
2019, 32(6): 80-89.
doi: 10.13275/j.cnki.lykxyj.2019.06.011
Abstract:
Objective Populus purdomii is one of the native host of Melampsora laricio-populina. DNA methylation may change the epigenetic rust resistance of P. purdomii. The purpose of this study is to understand the mechanism of poplar rust resistance. Method Different concentrations of methyl methane sulfonate (MMS) water solutions were applied to culture the 1-year-old P. purdomii seedlings, and urediospore suspensions with the same concentration were artificially inoculated on the abxial of leaves. Hereafter, epigenetic traits under various treatments were recorded consecutively, including the uredial density, the latent period, the plant mortality, the rate of leaf spots and curling symptoms. A spectrophotometric method was employed for monitoring the changes of the defense enzyme activities, involving SOD, CAT, POD and PPO during MMS treatments. Result MMS caused leaf curling, leaf blackness spots and even plant death with a positive correlation between the incidence and the MMS concentration, meanwhile, MMS also provided an chance for health seedlings survival under MMS treatments, the resistant seedlings displayed a more greener leaf and more thicker mesophyll tissues. Importantly, MMS treatment promoted the resistance of P. purdomii to M. larici-populina, the latent period of the pathogens was delayed for 1 to 2 days than that of the control group, the density of uredia decreased significantly with MMS concentration, and the activity of defense enzymes of the poplars changed correspondingly. Under the MMS treatments, the activities of SOD and POD tended to be down-regulated compared with the control group, CAT and PPO tended to be up-regulated, and the activity of POD and PPO was affected the most. However, during the infection of rust disease, all the four kinds of defense enzymes showed a relative trend of rising at first and then falling during MMS treatments. Among them, PPO showed a significant positive correlation with rust disease resistance (P=0.024). Conclusion MMS treatment will change the epigenetics by improving the quantitative rust resistance of Populus purdomii via delaying the latent period, decreasing uredial density and changing self-defense enzyme activity.
2019, 32(6): 90-98.
doi: 10.13275/j.cnki.lykxyj.2019.06.012
Abstract:
Objective To classifying the Picea tianschanica forest communities and study the effects of cutting intensity and environmental factors on the community pattern the purpose of sustainable management of Picea tianschanica forest. Method Based on field investigation, two-way indicator species analysis (TWINSPAN) was used to classify 47 Picea tianschanica communities, The redundancy analysis (RDA) was used to sort the community types and quantitatively isolate the factors affecting the community pattern. Result (1) The 47 survey plots were classified into sixteen types of forest communities by TWINSPAN; (2) According to RDA sort diagram, the main environmental factors affecting the communities distribution of Picea tianschanica forest were elevation, slope and cutting intensity of forest. (3) The interpretation rate of environmental variables to forest community pattern accounted for 33.9%, The explanation part of the cutting intensity disturbance factors in the distribution pattern of the community accounts for 5%, the percentage of the interaction between the two factors was about 17.9%. In addition, 43.2% of distribution pattern was undetermined. The inexplainable part mainly includes the mutual influence between communities and human interference. Conclusion The Picea tianschanica forest in Tianshan composes of 14 community types, the community distribution pattern are controlled by cutting intensity and environment factor. The diversity of community indicates that after the implementation of natural forest protection project, the vegetation restoration is well, and the magnitude of cutting intensity is great significance to forest sustainable management.
2019, 32(6): 99-105.
doi: 10.13275/j.cnki.lykxyj.2019.06.013
Abstract:
Objective This study aimed at cloning the cDNA sequence of Eucalyptus phenylalanin ammonia-lyase (PAL) gene, analyzing its characteristics, and investigating its expressions in Eucalyptus under the infection of Calonectria pseudoreteaudii. Method SOE-PCR technology was used to clone PAL gene from E. urophylla×E. tereticornis M1. The expression level of PAL gene in different Eucalyptus cultivars infected with C. pseudoreteaudii were analyzed by RT-PCR. Result One PAL gene was cloned. Its ORF sequence was 2 142 bp, and encoded 713 amino acids, which showed high similarity to the PAL from other Eucalyptus, with 99% identity. Amino acids sequence analysis indicated that the predicted PAL protein was a stable hydrophilic protein, including three phosphorylation sites (serine, threonine and tyrosine). Its secondary structure was rich in α-helix and random coil. The predicted protein contained phenylalanine and histidine ammonia-lyase conserved structure. The results showed that the PAL gene was significantly up-regulated in all tested cultivars. Moreover, the PAL gene was earlier and more significantly up-regulated in the stronger resistant cultivars. Conclusion The PAL gene which was cloned from E. urophylla×E. tereticornis M1 has typical characteristics of PAL family. It is speculated that PAL gene may participant in the synthesis of phenolic compounds or signal molecule salicylic acid, then improves the resistance of Eucalyptus to C. pseudoreteaudii.
2019, 32(6): 106-114.
doi: 10.13275/j.cnki.lykxyj.2019.06.014
Abstract:
Objective The purpose of this study is to select salt-tolerance Catalpa ovata provenances as the rootstock for C. bungei grafting, so as to expand the range suitable of C. bungei growth and alleviate the tight domestic demand for high-quality C.ovata seedlings. Method The seeds of 6 C. ovata provenances were collected. NaCl treatments were performed on these seeds to simulate salt stress. The salt tolerance were analyzed by test seed germination and seedling growth. The provenances showed strong salt tolerance were selected as provenances suitable to be used as rootstock to graft seedlings of C. bungei. The variation of germination, enzyme activity and soluble substances such as proline and MDA in the seedlings after 20 days'NaCl treatments (4 concentrations:0%, 0.3%, 0.6%, 1%) was measured. The correlation indexes of the data was calculated to select the proper evaluation indexes. Membership function method in fuzzy mathematics together with proportion was used to evaluate the NaCl tolerance of C. bungei from different provenances comprehensively. Result Under salt stress, the length, width, fin length and 1 000 grain weight of the seeds, and the content of MDA, proline, soluble sugar and soluble protein and SOD, POD, CAT activity among these seedlings from the 6 provenances showed significant differences. The length of radicle, hypocotyl and seedlings was also significantly changed under salt stress. The threshold NaCl concentration for the germination of these seeds was 0.6%. The salt resistance of C. bungei was comprehensively evaluated using indexes under threshold NaCl concentration. Conclusion For breeding C. bungei grafted seedlings in saline soil, the provenance from Hengren of Liaoning Province is the most suitable for the rootstock seedlings of C.ovata, while the provenance from Luoyang of Henan Province is the least suitable provenance.
2019, 32(6): 115-121.
doi: 10.13275/j.cnki.lykxyj.2019.06.015
Abstract:
Objective To establish a rapid, simple, reproducible and high yield extraction method of Eucommia ulmoides gum particle in order to investigate its plasma membrane components, including membrane protein, fatty acid, glycolipid and the molecular weight of E. ulmoides gum. Method The leaf and samara of E. ulmoides were selected as extracted materials for analyzing the extraction ratio of E. ulmoides gum particle by changing centrifugal condition and number of grinding, combining with the results of light microscope and electron microscope observation. Result The results showed that the liquid nitrogen quick-frozen E. ulmoides samples (leaf or samara) via 6 times grind, 10 times filter, 5 000 g centrifugal force (45°constant angle) at 4℃ for 10 minutes and 8 times rinse with washing buffer could produce higher extraction yield. Under this condition, the extraction ratios of gum particle from E. ulmoides leaf and samara collected in October, 2018 were 3.70 g·kg-1 and 5.37 g·kg-1, respectively. Further, the morphological observations indicated the size and accumulated content of E. ulmoides gum particle appeared the change rule of increasing at first and then stabilizing and there were significant difference in grain diameter between these gum particles. The results from electron microscopy observation found that small gum particles (1 4 μm) and medium gum particles (4 7 μm) respectively from E. ulmoides leaf, samara and bark (collected in October, 2018) accounted for 39%, 53%, 98.38% and 38%, 34%, 0.12%, while the content of the large gum particles (7 11 μm) were 23%, 13%, 0.05%, respectively. Conclusion A modified approach is proposed to improve the extract efficiency of E. ulmoides gum particles which could be extensively applicable to extraction of gum particles from different organs and tissues of E. ulmoides.
2019, 32(6): 122-129.
doi: 10.13275/j.cnki.lykxyj.2019.06.016
Abstract:
Objective To study the oil accumulation and the changes of mineral elements in the pecan (Carya illinoinensis) fruit during the late development stage, and provide a theoretical basis for further research on the transformation and regulation of pecan oil. Method The pecan varieties 'Mahan' and 'No. 28' were used as experimental materials. Through studying the fruit quality, the oil transformation and the dynamic change of crude fat content, fatty acid composition and mineral elements content in different part of fruit in the later stage of fruit development, the relationship between oil accumulation and mineral elements was investigated. Result The results showed that the unsaturated fatty acid content of fruit kernel increased and then decreased in the later stage of pecan fruit development. The crude fat content and fatty acid content of fruit kernel were different with fruit development, for 'No. 28', the crude fat content in fruit kernel increased continuously, while for 'Mahan', after increasing, the crude fat content showed a slight decreasing trend. The content of oleic acid and stearic acid increased, while the arachidic acid and palmitic acid decreased gradually. The content of linoleic acid and linolenic acid increased at first and then decreased in 'Mahan', but decreased in 'No. 28'. There was a significant or extremely significant negative correlations between the crude fat accumulation and the mineral elements content such as nitrogen, phosphorus, potassium and calcium in fruit kernels. Conclusion The fat content in fruit kernel increases and the fatty acid composition in the oil changes with the development, and There is a tendency of conversion from saturated fatty acid to unsaturated fatty acid. There are differences among varieties in the changes of crude fat content of fruit kernel and fatty acid content of oil during the development of fruit. The contents of mineral elements such as nitrogen, phosphorus, potassium and calcium in the late stage of pecan fruit development are significantly correlated with the accumulation of oil, and these mineral elements may play a role in the accumulation of oil and fatty acid transformation of pecan fruits.
2019, 32(6): 130-136.
doi: 10.13275/j.cnki.lykxyj.2019.06.017
Abstract:
Grassland is a major component and important resource of terrestrial ecosystem and has important production and ecological functions. However, the grassland in China has faced with severe ecological problems such as water resource shortage and vegetation degradation due to global climate change and long-term irrational utilization, which poses a serious threat to the stability of ecosystem. Therefore, quantitatively studying the hydrologic cycle of grassland ecosystem provides important application value and significant guidance for the protection and sustainable development of grassland ecosystem. Stable isotopes of carbon, hydrogen and oxygen are natural tracers in water body and plant tissue, with high sensitivity and accuracy. Stable isotopes of hydrogen and oxygen can be used to systematically and quantitatively clarify the hydrologic cycle and processes of grassland ecosystem, the conversion relationship between water bodies, the water use strategy of plants and the response mechanism of vegetation to global climate change. In this article, the basic concept and principle of stable isotopes are reviewed. The research methods for examining the hydrologic cycle of grassland ecosystems and their application are summarized and analyzed. Progresses in the application of hydrogen and oxygen stable isotopes in the hydrologic process of grassland ecosystem are extensively discussed, including atmospheric precipitation, runoff, soil water, groundwater, water source for plants, and evaporation, and the application of carbon stable isotope in plant water use efficiency. The problems and future researches of stable isotope techniques in the study of hydrologic cycle are discussed and analyzed.
Grassland is a major component and important resource of terrestrial ecosystem and has important production and ecological functions. However, the grassland in China has faced with severe ecological problems such as water resource shortage and vegetation degradation due to global climate change and long-term irrational utilization, which poses a serious threat to the stability of ecosystem. Therefore, quantitatively studying the hydrologic cycle of grassland ecosystem provides important application value and significant guidance for the protection and sustainable development of grassland ecosystem. Stable isotopes of carbon, hydrogen and oxygen are natural tracers in water body and plant tissue, with high sensitivity and accuracy. Stable isotopes of hydrogen and oxygen can be used to systematically and quantitatively clarify the hydrologic cycle and processes of grassland ecosystem, the conversion relationship between water bodies, the water use strategy of plants and the response mechanism of vegetation to global climate change. In this article, the basic concept and principle of stable isotopes are reviewed. The research methods for examining the hydrologic cycle of grassland ecosystems and their application are summarized and analyzed. Progresses in the application of hydrogen and oxygen stable isotopes in the hydrologic process of grassland ecosystem are extensively discussed, including atmospheric precipitation, runoff, soil water, groundwater, water source for plants, and evaporation, and the application of carbon stable isotope in plant water use efficiency. The problems and future researches of stable isotope techniques in the study of hydrologic cycle are discussed and analyzed.
2019, 32(6): 137-143.
doi: 10.13275/j.cnki.lykxyj.2019.06.018
Abstract:
Objective The temporal variations of appearance, nutrition and eating quality of Phyllostachys prominens shoots at different harvest time were analyzed aiming at providing reference for the cultivation and production of high quality bamboo shoots. Method The appearance quality, nutrient quality and eating quality of bamboo shoots harvested at different times (1 day, 2 days and 3 days after unearthed and unearthed) were investigated. Result The harvest time significantly affected the length, weight, and the contents of fat, vitamin C, isoleucine, leucine, lysine and lignose, tannin, oxalic acid, total flavone in bamboo shoots (P < 0.05), but less affected the content of protein, soluble sugar, starch, sucrose, and cellulose (P>0.05), and no significant difference was found in the content of other amino acids, essential amino acids, total amino acid, flavored amino acids and the proportion of essential amino acids, flavored amino acids in bamboo shoots harvested at different time too(P>0.05). Conclusion It is suggested that there are obvious temporal variation in the appearance quality and eating quality of Phyllostachys prominens shoots after unearthed, the main influential components of eating quality are lignose, tannin, oxalic acid, total flavone, the effect of harvest time on flavor amino acids is small. Nutritional quality changed to some extents. Therefore, from the viewpoint of high quality bamboo shoot production, bamboo shoots within 1 day after unearthed should be harvested in time.
2019, 32(6): 144-150.
doi: 10.13275/j.cnki.lykxyj.2019.06.019
Abstract:
Objective To study the changes of key endogenous substances during flowering process in Luculia gratissima 'Xiangfei' and try to provide references for artificial regulating of flowering time. Method The buds from various stages, including vegetative growth phase, undifferentiation phase, bract primordium differentiation phase, inflorescence primordium differentiation phase and small flower primordium differentiation phase, were selected, the content of IAA, ABA, GA3, ZT, soluble sugar and soluble protein were determined at the five stages, and the role of endogenous substances for flowering of L. gratissima 'Xiangfei' under induced photoperiod were analyzed and compared with non-induced photoperiod. Result GA3 was not detected at the five phases because of its extremely low content. The content of soluble sugar, ZT, and the ratio of soluble sugar/protein was the highest at the vegetative growth phase, and gradually decreased with the advancement of floral transition process under the inductive photoperiod. The content of soluble protein was in medium level at the vegetative growth phase, the highest at the undifferentiation and inflorescence primordium differentiation phase, and the lowest at the bract and small flower primordium differentiation phase. The IAA content was the highest at the vegetative growth phase among these stages. Although it increased at inflorescence primordium differentiation phase under the inductive photoperiod, its level was still lower than that of the vegetative growth phase. The ABA content and ABA/ZT ratio was the lowest at the vegetative growth phase, and increased gradually with the advancement of floral transition process, and then decreased at small flower primordium differentiation phase. The ratio of ABA/IAA increased gradually during flowering process. The ZT/IAA ratio increased drastically before bract primordium differentiation phase, then decreased later, and stayed at certain levels lower than that of vegetative growth phase. Conclusion Compared with the non-induced photoperiod, higher levels of ABA, ABA/IAA and ABA/ZT, and lower levels of IAA, ZT, soluble sugar and soluble sugar/protein are beneficial to flowering of L. gratissima 'Xiangfei' under the induced photoperiod. Higher level of ZT/IAA could benifit the floral physiological differentiation, and lower level is beneficial to the floral morphological differentiation.
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