While numerous allometric models exist for estimating biomass in trees with single stems,models for multi-stemmed species are scarce.This study presents models for predicting aboveground biomass(AGB)in European hazel(...While numerous allometric models exist for estimating biomass in trees with single stems,models for multi-stemmed species are scarce.This study presents models for predicting aboveground biomass(AGB)in European hazel(Corylus avellana L.),growing in multi-stemmed shrub form.We measured the size and harvested the biomass of 30 European hazel shrubs,drying and weighing their woody parts and leaves separately.AGB(dry mass)and leaf area models were established using a range of predictors,such as the upper height of the shrub,number of shoots per shrub,canopy projection area,stem base diameter of the thickest stem,and the sum of cross-sectional areas of all stems at the stem base.The latter was the best predictor of AGB,but the most practically useful variables,defined as relatively easy to measure by terrestrial or aerial approaches,were the upper height of the shrub and the canopy projection area.The leaf biomass to AGB ratio decreased with the shrub's height.Specific leaf area of shaded leaves increases with shrub height,but that of leaves at the top of the canopy does not change significantly.Given that the upper shrub height and crown projection of European hazel can be estimated using remote sensing approaches,especially UAV and LIDAR,these two variables appear the most promising for effective measurement of AGB in hazel.展开更多
With the growth of global protein demand and the development of plant-based foods,pea protein,as a low-allergenic,nutritionally balanced and environmentally friendly plant protein,has shown great potential in replacin...With the growth of global protein demand and the development of plant-based foods,pea protein,as a low-allergenic,nutritionally balanced and environmentally friendly plant protein,has shown great potential in replacing animal protein.Pea protein is mainly composed of globulin and albumin,with a protein content of 20%to 30%,and has a balanced amino acid composition,as well as being rich in minerals and dietary fiber.It also possesses good foaming,gelling,emulsifying and antioxidant functional properties.However,pea protein also has inherent defects that limit its application in the food industry.This article systematically reviews the extraction techniques,functional properties,modification methods and application fields of pea protein,and focuses on evaluating the effects of different extraction and modification strategies on protein yield and functional properties.Research shows that ultrasonic-assisted alkaline extraction can reduce solvent usage by 55%,shorten extraction time by 50%,and increase extraction rate by 12.51%;under optimized conditions,ultrafiltration membrane technology can achieve a protein purity of 91%.In terms of modification,ultrasonic treatment increases foaming capacity by 37.4%,and phenolic cross-linking increases gel strength from 3.0 kPa to 48 kPa.This article provides data support and theoretical reference for the efficient extraction and functional optimization of pea protein,and has promoting significance for its wide application in plant-based foods.展开更多
This study was conducted at Fafan Research Center, Golajo research site to evaluate the effect of Moringa stenopetala and pigeon pea leaf supplementation on growth performance of short-eared Somali goat breed. A total...This study was conducted at Fafan Research Center, Golajo research site to evaluate the effect of Moringa stenopetala and pigeon pea leaf supplementation on growth performance of short-eared Somali goat breed. A total of fifteen yearling indigenous short-eared Somali goat breeds with an initial weight of 15.2 ± 0.30 kg were assigned to three treatment groups using completely randomized design. Pigeon pea (Pp) and Moringa stenopetala (MS) feeds were formulated using 0%, 5%, and 10% inclusion levels of MSLM and PPLM as experimental diets, respectively. The feed of the experiment was prepared in two levels (2 kg of Moringa stenopetala and 2 kg of pigeon pea) and was supplemented to experimental animals in treatments one and two, respectively. The average e initial body weight of selected male goats was 18.82 ± 0.37, 18.8 ± 0.37 and 17.8 ± 0.37 kg under treatment groups T1, T2 and control respectively. Data was analyzed using general linear model (GLM) procedure of SAS computer package Version 9.0 (SAS, 2002). The final weights gain (FWG) of goats on T1 and T2 of experimental group was significantly (P 0.05) the final weight gain of goat supplemented on Moringa stenopetala (T1) and pigeon pea levels (T2). The mean average weight gains (AWG) obtained from the supplemented group in this study were 7.50 ± 0.37 and 7.82 ± 0.37 kg for T1 and T2, whereas mean weight gains for un-supplemented goats were found to be 6.26 ± 0.37 kg. Feeding of dried Moringa stenopetala and pigeon pea leaves mixture improved body weights and average daily body weight gain without affecting feed intake and overall health of Somali goat breed. As Moringa stenopetala and pigeon pea leaves are rich nitrogen/protein source, they can be used effectively as substitute for conventional concentrate in the diet of growing goats at small holder farmer’s level where they can be grown in abundance. Therefore, for higher quality of forage and higher total DM yield for animal feeding, moringa should be harvested at wider harvesting intervals of at least 6th- to 8th-week intervals. Similarly, for pigeon peas, 4- to 6-week harvesting interval can result in optimum forage as well as feed quality and resulted in better growth performances for Somali short-eared goat breeds.展开更多
Grassland shrub encroachment is a phenomenon that is prevalent in arid and semi-arid regions worldwide,impacting grassland ecosystems in several ways.In the context of escalating climate change and human activities,ex...Grassland shrub encroachment is a phenomenon that is prevalent in arid and semi-arid regions worldwide,impacting grassland ecosystems in several ways.In the context of escalating climate change and human activities,examining the nutrient and stoichiometric characteristics of Spiraea shrubs in grassland ecosystems,along with their relationships with environmental factors,can yield valuable insights into the nutrient utilization and survival strategies of these shrubs.This,in turn,offers a scientific foundation for developing future conservation measures.This study was conducted in July 2023 in the Altay Mountains,Northwest China,where Spiraea shrubs thrive across five grassland types:temperate steppe desert,temperate desert steppe,temperate steppe,temperate meadow steppe,and mountain meadow.Leaf and soil samples were collected from each grassland type to analyze the concentrations of carbon(C),nitrogen(N),and phosphorus(P),as well as the stoichiometric characteristics of both the leaves and soil.Subsequently,correlation analysis and redundancy analysis(RDA)were conducted to investigate the variations in leaf C,N,and P concentrations and leaf stoichiometry of Spiraea shrubs as well as their influencing factors.The results indicated the presence of significant or highly significant differences(P<0.050)in the leaf C,N,and P concentrations and leaf stoichiometry(C:N,C:P,and N:P ratios)of Spiraea shrubs across the five grassland types.The N:P ratios of Spiraea shrub leaves in the five grassland types ranged from 7.37 to 11.77,suggesting that N availability generally limits the growth of Spiraea shrubs.Results of RDA revealed that the most significant contributors to the C,N,and P concentrations and stoichiometric characteristics of Spiraea shrub leaves were in the following order:soil total N>mean annual precipitation>elevation>soil pH>soil organic C>mean annual temperature.These factors had contribution rates of 35.32%,13.19%,10.20%,8.82%,8.34%,and 6.48%,respectively.It was determined that soil nutrients have a greater impact on the growth and nutrient accumulation of Spiraea shrubs compared to climatic factors.This study makes an important contribution to the theoretical basis and data support,enabling a deeper understanding of the response mechanisms of shrub species in the grassland ecosystems of the Altay Mountains to climate change.展开更多
The Miombo ecoregion covers eastern and southern Africa,with variations in plant species composition,structure,and biomass across a broad precipitation gradient.Most studies of woody plant communities focus exclusivel...The Miombo ecoregion covers eastern and southern Africa,with variations in plant species composition,structure,and biomass across a broad precipitation gradient.Most studies of woody plant communities focus exclusively on larger overstorey trees(≥5 or≥10cm stem diameter),overlooking the contribution of small trees and shrubs in the understorey,which can comprise a significant portion of total biomass and diversity.Here,we evaluate the contribution of both large overstorey and small understorey woody plants to species diversity and above-ground biomass(AGB),with 17 plots(0.5-1ha)across five sites representing both extremes of rainfall gradient spanning the Miombo ecoregion,in northeast Namibia(500-700mm mean annual precipitation,MAP)and southern Democratic Republic of Congo(DRC)(>1,200mm MAP).Mean AGB per site ranged from 21 to 119Mg·ha^(-1),increasing with rainfall,while the proportional AGB contribution of small trees,saplings,and shrubs decreased.In dry Namibia,small trees,saplings,and shrubs(<5cm DBH)contributed up to 28.2%of total AGB(mean±standard deviation:18.3%±3.4%),whereas in wet DRC,they contributed only up to 2.5%(2.3%±1.4%).Namibian sites,on average,contained a large proportion of woody species diversity exclusively in small trees and shrubs(<5cm DBH),with 55 species representing 59.4%of the total diversity.In contrast,DRC sites had higher overall small woody plant diversity(66 species)but fewer species found exclusively as small individuals(25.2%),with many saplings that grow to larger trees.Understorey composition also differed,with saplings of overstorey trees dominating in DRC,while shrubs dominated in Namibia.Our findings show that woody biomass and diversity in dry woodlands are substantially underestimated when studies focus only on larger trees.This highlights the need to consider all woody vegetation to better understand woody plant diversity and biomass variation.展开更多
An approximately 800 bp cDNA ( Lhcb 2) encoding light_harvesting chlorophyll a/b_binding protein complex (type Ⅱ) was cloned from the seedling of pea ( Pisum sativum L.) with RT_PCR method. Southern blotting usi...An approximately 800 bp cDNA ( Lhcb 2) encoding light_harvesting chlorophyll a/b_binding protein complex (type Ⅱ) was cloned from the seedling of pea ( Pisum sativum L.) with RT_PCR method. Southern blotting using special probe demonstrated that there existed one copy of Lhcb 2 in pea genome. RT_PCR and Northern blotting revealed the expression of Lhcb 2 which was regulated by light in a time_dependent expression manner. The Lhcb 2 gene didn't express untill 2 h after irradiated with white light. Low temperature (4 ℃) also affected the Lhcb 2 gene by decreasing half of its expression under 25 ℃.展开更多
Lectin and leghemoglobin in legumes play the important roles, respectively, in recognition of host plants to their rhizobial bacteria, and lowering the oxygen partial pressure around bacteroids and protecting nitrogen...Lectin and leghemoglobin in legumes play the important roles, respectively, in recognition of host plants to their rhizobial bacteria, and lowering the oxygen partial pressure around bacteroids and protecting nitrogenase from oxygen in symbiotic nitrogen-fixing nodules. In order to extend the host range of the rhizobial bacteria and to make them fix nitrogen in non-legumes, pea lectin gene (pl) and Parasponia hemoglobin gene ( phl,) have been constructed into a plant expression vector (pCBHUL) and the vector pCBHUL was introduced into rice calli from immature young embryos by particle bombardment. After the calli were regenerated into plantlets on the resistant-selecting media containing hygromycin, they were identified by PCR and Southern blot hybridization. It was indicated that the pi and phb genes were integrated into nucleic genome of the transformed rice plants. GUS activity and the product of the pi gene were determined by GUS staining, Western blot and in situ hybridization at translational level. Eighteen out of 40 plants resistant to hygromycin were positively identified by PCR analysis with the rate of 45%. The pi gene was expressed in 3 out of 18 plants with 17% and 7.5% in 40 plants. The results may provide a clue for exploring whether Rhizobium leguminosarum by. viceae could extend its host range and make the transgenic rice plants have the possibility of being symbiotic, or associative to nitrogen fixation.展开更多
Biomass and net primary productivity （NPP） are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos P...Biomass and net primary productivity （NPP） are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos Plateau were investigated with method of harvesting standard size shrub in the growing season （June-October） of 2006. Results indicated that above- and belowground biomass of the same size shrubs showed no significant variation in the growing season （p〉0.1）, but annual biomass varied significantly （p〈 0.01）. In the A. ordosica community, shrub biomass storage was 699.76-1246.40 g.m^-2 and annual aboveground NPP was 224.09 g-m^-2·a^-1. Moreover, shrub biomass and NPP were closely related with shrub dimensions （cover and height） and could be well predicted by shrub volume using power regression.展开更多
As a seed transmitted pathogen, pea seed_borne mosaic virus (PSbMV) not only replicates in embryonic cells but can also withstand seed desiccation. To understand the mechanism of PSbMV tolerance to seed desiccation, ...As a seed transmitted pathogen, pea seed_borne mosaic virus (PSbMV) not only replicates in embryonic cells but can also withstand seed desiccation. To understand the mechanism of PSbMV tolerance to seed desiccation, the authors compared the stability of viral coat protein (CP) and the distribution of viral particles in the cotyledon cells of pea (Pisum sativum L.) embryos collected before and after the dehydration process. Before dehydration, when the embryo was fresh and immature, degradation of CP was observed and a predominantly perinuclear distribution of viral particles in the cotyledon cells was evident. After dehydration, when the embryo was dry and mature, degradation of CP did not occur and the perinuclear viral distribution disappeared. Instead, aggregates containing PSbMV CP were found in the cytoplasm. Electron microscopy showed that these aggregates were composed of PSbMV particles. The formation of PSbMV particle aggregates is apparently triggered by seed dehydration and may be favorable to the virus survival in the desiccated embryonic cells.展开更多
To study the function and adaptive mechanism of tonoplast H + ATPase under salt stress, pea ( Pisum sativum L.) seedlings were treated with different concentrations of salt (100-250 mmol/L NaCl) and with 100 mmol...To study the function and adaptive mechanism of tonoplast H + ATPase under salt stress, pea ( Pisum sativum L.) seedlings were treated with different concentrations of salt (100-250 mmol/L NaCl) and with 100 mmol/L NaCl for different days (1-3 d). The ATP hydrolytic activity and the proton transport activity and the changes of the amount of tonoplast H + ATPase (subunit A) were measured. ATP hydrolytic activity of H + ATPase prepared from plants treated with 250 mmol/L NaCl was reduced by about 25% compared to that of control plants, but that of stressed plants treated with 100 mmol/L and 200 mmol/L NaCl was unchanged. The activity from plants treated with 100 mmol/L NaCl for up to 3 d was lower than that of control plants by 20%. But the proton transport activity was increased under the same salt stresses as above. These results showed that the changes of the hydrolytic activity and the proton transport activity were not in proportion and salt stress may cause the change of the coupling ratio of H + transport activity to ATP hydrolysis. The protein amount kept unchanged and reduced a little only when pea was treated with 100 mmol/L NaCl for 3 d. These results indicated that salinity stimulated the increase of the pump efficiency of the V_ATPase from pea roots, which was due to the change of the coupling ratio, but not due to the increase of ATP hydrolysis and the amount of V_ATPase.展开更多
[ Objective] The aim of this study was to discuss the effect of antioxidants and lipid peroxidation from pea crops of plateau. [ Method] SOD enzyme liquid from pea crops of plateau was extracted by means of protein co...[ Objective] The aim of this study was to discuss the effect of antioxidants and lipid peroxidation from pea crops of plateau. [ Method] SOD enzyme liquid from pea crops of plateau was extracted by means of protein concentration assay, enzyme activity assay and antioxidant activity determination by DPPH method, peroxide activity inhibition of in vitro tissues from mice by homogenate MDA colorimetry method and lipid peroxidation assay of in vitro tissues. [ Result ] IC50 of the crude enzyme liquid extracted from pea on DPPH was 55.16 mg/L, while the scavenging rate of the crude enzyme liquid was lower than that of ascorbic acid, tea polyphenol and citric acid with the same concentration. The synergistic effect was found in ascorbic acid and crude enzyme liquid, but the synergism of ascorbic acid was better than that of citric acid. IC50 of SOD enzyme liquid extracted from pea on DPPH was 11.1 mg/L, which was better than that of tea polyphenol and closely similar to that of ascorbic acid. SOD enzyme liquid extracted from pea had an inhibitory effect on MDA production from in vitro tissues such as liver, kidney and heart, especially for a significantly inhibitory effect on MDA from liver in vitro. When the concentration was 0.25 mg/ml, the inhibition rate reached 78.3%, and then the inhibition rate increased little with the concentration incresas, while its effect on heart and kidney were inferior. [ Conclusion] SOD crude enzyme liquid and SOD enzyme liquid extracted from pea all have certain DPPH scavenging capacity, while SOD enzyme liquid extracted from pea has an inhibitory effect on lipid peroxidation.展开更多
基金funded by grants EVA4.0 No.Z.02.1.01/0.0/0.0/16_019/0000803 and ITMS2014+313011W580s provided by EU OP RDEin CZ and SKprojects APVV-18-0086,APVV-19-0387,APVV-20-0168,APVV-20-0215 and APVV-22-0056 from the Slovak Research and Development Agencysupport from the European Research Executive Agency for ReForest,Grant Agreement Nr:101060635
文摘While numerous allometric models exist for estimating biomass in trees with single stems,models for multi-stemmed species are scarce.This study presents models for predicting aboveground biomass(AGB)in European hazel(Corylus avellana L.),growing in multi-stemmed shrub form.We measured the size and harvested the biomass of 30 European hazel shrubs,drying and weighing their woody parts and leaves separately.AGB(dry mass)and leaf area models were established using a range of predictors,such as the upper height of the shrub,number of shoots per shrub,canopy projection area,stem base diameter of the thickest stem,and the sum of cross-sectional areas of all stems at the stem base.The latter was the best predictor of AGB,but the most practically useful variables,defined as relatively easy to measure by terrestrial or aerial approaches,were the upper height of the shrub and the canopy projection area.The leaf biomass to AGB ratio decreased with the shrub's height.Specific leaf area of shaded leaves increases with shrub height,but that of leaves at the top of the canopy does not change significantly.Given that the upper shrub height and crown projection of European hazel can be estimated using remote sensing approaches,especially UAV and LIDAR,these two variables appear the most promising for effective measurement of AGB in hazel.
文摘With the growth of global protein demand and the development of plant-based foods,pea protein,as a low-allergenic,nutritionally balanced and environmentally friendly plant protein,has shown great potential in replacing animal protein.Pea protein is mainly composed of globulin and albumin,with a protein content of 20%to 30%,and has a balanced amino acid composition,as well as being rich in minerals and dietary fiber.It also possesses good foaming,gelling,emulsifying and antioxidant functional properties.However,pea protein also has inherent defects that limit its application in the food industry.This article systematically reviews the extraction techniques,functional properties,modification methods and application fields of pea protein,and focuses on evaluating the effects of different extraction and modification strategies on protein yield and functional properties.Research shows that ultrasonic-assisted alkaline extraction can reduce solvent usage by 55%,shorten extraction time by 50%,and increase extraction rate by 12.51%;under optimized conditions,ultrafiltration membrane technology can achieve a protein purity of 91%.In terms of modification,ultrasonic treatment increases foaming capacity by 37.4%,and phenolic cross-linking increases gel strength from 3.0 kPa to 48 kPa.This article provides data support and theoretical reference for the efficient extraction and functional optimization of pea protein,and has promoting significance for its wide application in plant-based foods.
文摘This study was conducted at Fafan Research Center, Golajo research site to evaluate the effect of Moringa stenopetala and pigeon pea leaf supplementation on growth performance of short-eared Somali goat breed. A total of fifteen yearling indigenous short-eared Somali goat breeds with an initial weight of 15.2 ± 0.30 kg were assigned to three treatment groups using completely randomized design. Pigeon pea (Pp) and Moringa stenopetala (MS) feeds were formulated using 0%, 5%, and 10% inclusion levels of MSLM and PPLM as experimental diets, respectively. The feed of the experiment was prepared in two levels (2 kg of Moringa stenopetala and 2 kg of pigeon pea) and was supplemented to experimental animals in treatments one and two, respectively. The average e initial body weight of selected male goats was 18.82 ± 0.37, 18.8 ± 0.37 and 17.8 ± 0.37 kg under treatment groups T1, T2 and control respectively. Data was analyzed using general linear model (GLM) procedure of SAS computer package Version 9.0 (SAS, 2002). The final weights gain (FWG) of goats on T1 and T2 of experimental group was significantly (P 0.05) the final weight gain of goat supplemented on Moringa stenopetala (T1) and pigeon pea levels (T2). The mean average weight gains (AWG) obtained from the supplemented group in this study were 7.50 ± 0.37 and 7.82 ± 0.37 kg for T1 and T2, whereas mean weight gains for un-supplemented goats were found to be 6.26 ± 0.37 kg. Feeding of dried Moringa stenopetala and pigeon pea leaves mixture improved body weights and average daily body weight gain without affecting feed intake and overall health of Somali goat breed. As Moringa stenopetala and pigeon pea leaves are rich nitrogen/protein source, they can be used effectively as substitute for conventional concentrate in the diet of growing goats at small holder farmer’s level where they can be grown in abundance. Therefore, for higher quality of forage and higher total DM yield for animal feeding, moringa should be harvested at wider harvesting intervals of at least 6th- to 8th-week intervals. Similarly, for pigeon peas, 4- to 6-week harvesting interval can result in optimum forage as well as feed quality and resulted in better growth performances for Somali short-eared goat breeds.
基金supported by the National Natural Science Foundation of China(W2412123)the Youth Top Talents Project of"Tianshan Talent"Training Plan of Xinjiang Uygur Autonomous Region,China(2022TSYCCX0011)+1 种基金the Tianshan Talents Project of Xinjiang Uygur Autonomous Region,China(2022TSYCLJ0056)the Self-deployment Program of Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences(E350030401).
文摘Grassland shrub encroachment is a phenomenon that is prevalent in arid and semi-arid regions worldwide,impacting grassland ecosystems in several ways.In the context of escalating climate change and human activities,examining the nutrient and stoichiometric characteristics of Spiraea shrubs in grassland ecosystems,along with their relationships with environmental factors,can yield valuable insights into the nutrient utilization and survival strategies of these shrubs.This,in turn,offers a scientific foundation for developing future conservation measures.This study was conducted in July 2023 in the Altay Mountains,Northwest China,where Spiraea shrubs thrive across five grassland types:temperate steppe desert,temperate desert steppe,temperate steppe,temperate meadow steppe,and mountain meadow.Leaf and soil samples were collected from each grassland type to analyze the concentrations of carbon(C),nitrogen(N),and phosphorus(P),as well as the stoichiometric characteristics of both the leaves and soil.Subsequently,correlation analysis and redundancy analysis(RDA)were conducted to investigate the variations in leaf C,N,and P concentrations and leaf stoichiometry of Spiraea shrubs as well as their influencing factors.The results indicated the presence of significant or highly significant differences(P<0.050)in the leaf C,N,and P concentrations and leaf stoichiometry(C:N,C:P,and N:P ratios)of Spiraea shrubs across the five grassland types.The N:P ratios of Spiraea shrub leaves in the five grassland types ranged from 7.37 to 11.77,suggesting that N availability generally limits the growth of Spiraea shrubs.Results of RDA revealed that the most significant contributors to the C,N,and P concentrations and stoichiometric characteristics of Spiraea shrub leaves were in the following order:soil total N>mean annual precipitation>elevation>soil pH>soil organic C>mean annual temperature.These factors had contribution rates of 35.32%,13.19%,10.20%,8.82%,8.34%,and 6.48%,respectively.It was determined that soil nutrients have a greater impact on the growth and nutrient accumulation of Spiraea shrubs compared to climatic factors.This study makes an important contribution to the theoretical basis and data support,enabling a deeper understanding of the response mechanisms of shrub species in the grassland ecosystems of the Altay Mountains to climate change.
基金funded by the following grants:the Natural Environ-ment Research Council-Funded SECO Project(NE/T01279X/1)the Fostering Research&Intra-African Knowledge Transfer Through Mobility&Education(FRAME)Conservation Action Research Network(CARN)through the ASPIRE Grant Programme.
文摘The Miombo ecoregion covers eastern and southern Africa,with variations in plant species composition,structure,and biomass across a broad precipitation gradient.Most studies of woody plant communities focus exclusively on larger overstorey trees(≥5 or≥10cm stem diameter),overlooking the contribution of small trees and shrubs in the understorey,which can comprise a significant portion of total biomass and diversity.Here,we evaluate the contribution of both large overstorey and small understorey woody plants to species diversity and above-ground biomass(AGB),with 17 plots(0.5-1ha)across five sites representing both extremes of rainfall gradient spanning the Miombo ecoregion,in northeast Namibia(500-700mm mean annual precipitation,MAP)and southern Democratic Republic of Congo(DRC)(>1,200mm MAP).Mean AGB per site ranged from 21 to 119Mg·ha^(-1),increasing with rainfall,while the proportional AGB contribution of small trees,saplings,and shrubs decreased.In dry Namibia,small trees,saplings,and shrubs(<5cm DBH)contributed up to 28.2%of total AGB(mean±standard deviation:18.3%±3.4%),whereas in wet DRC,they contributed only up to 2.5%(2.3%±1.4%).Namibian sites,on average,contained a large proportion of woody species diversity exclusively in small trees and shrubs(<5cm DBH),with 55 species representing 59.4%of the total diversity.In contrast,DRC sites had higher overall small woody plant diversity(66 species)but fewer species found exclusively as small individuals(25.2%),with many saplings that grow to larger trees.Understorey composition also differed,with saplings of overstorey trees dominating in DRC,while shrubs dominated in Namibia.Our findings show that woody biomass and diversity in dry woodlands are substantially underestimated when studies focus only on larger trees.This highlights the need to consider all woody vegetation to better understand woody plant diversity and biomass variation.
文摘An approximately 800 bp cDNA ( Lhcb 2) encoding light_harvesting chlorophyll a/b_binding protein complex (type Ⅱ) was cloned from the seedling of pea ( Pisum sativum L.) with RT_PCR method. Southern blotting using special probe demonstrated that there existed one copy of Lhcb 2 in pea genome. RT_PCR and Northern blotting revealed the expression of Lhcb 2 which was regulated by light in a time_dependent expression manner. The Lhcb 2 gene didn't express untill 2 h after irradiated with white light. Low temperature (4 ℃) also affected the Lhcb 2 gene by decreasing half of its expression under 25 ℃.
文摘Lectin and leghemoglobin in legumes play the important roles, respectively, in recognition of host plants to their rhizobial bacteria, and lowering the oxygen partial pressure around bacteroids and protecting nitrogenase from oxygen in symbiotic nitrogen-fixing nodules. In order to extend the host range of the rhizobial bacteria and to make them fix nitrogen in non-legumes, pea lectin gene (pl) and Parasponia hemoglobin gene ( phl,) have been constructed into a plant expression vector (pCBHUL) and the vector pCBHUL was introduced into rice calli from immature young embryos by particle bombardment. After the calli were regenerated into plantlets on the resistant-selecting media containing hygromycin, they were identified by PCR and Southern blot hybridization. It was indicated that the pi and phb genes were integrated into nucleic genome of the transformed rice plants. GUS activity and the product of the pi gene were determined by GUS staining, Western blot and in situ hybridization at translational level. Eighteen out of 40 plants resistant to hygromycin were positively identified by PCR analysis with the rate of 45%. The pi gene was expressed in 3 out of 18 plants with 17% and 7.5% in 40 plants. The results may provide a clue for exploring whether Rhizobium leguminosarum by. viceae could extend its host range and make the transgenic rice plants have the possibility of being symbiotic, or associative to nitrogen fixation.
基金National Natural Sciences Foundation of China (Nos. 40501072 and 40673067)the Major State Basic Research Develop-ment Program of China (No. 2002CB 412503)the Knowledge In-novation Program of the Institute of Geographic Sciences and Natural Resources Research,CAS "The effect of human activities on regional envi-ronmental quality, the health risk and the environmental remediation"
文摘Biomass and net primary productivity （NPP） are two important parameters in determining ecosystem carbon pool and carbon sequestration. The biomass storage and NPP in desert shrubland of Artemisia ordosica on Ordos Plateau were investigated with method of harvesting standard size shrub in the growing season （June-October） of 2006. Results indicated that above- and belowground biomass of the same size shrubs showed no significant variation in the growing season （p〉0.1）, but annual biomass varied significantly （p〈 0.01）. In the A. ordosica community, shrub biomass storage was 699.76-1246.40 g.m^-2 and annual aboveground NPP was 224.09 g-m^-2·a^-1. Moreover, shrub biomass and NPP were closely related with shrub dimensions （cover and height） and could be well predicted by shrub volume using power regression.
文摘As a seed transmitted pathogen, pea seed_borne mosaic virus (PSbMV) not only replicates in embryonic cells but can also withstand seed desiccation. To understand the mechanism of PSbMV tolerance to seed desiccation, the authors compared the stability of viral coat protein (CP) and the distribution of viral particles in the cotyledon cells of pea (Pisum sativum L.) embryos collected before and after the dehydration process. Before dehydration, when the embryo was fresh and immature, degradation of CP was observed and a predominantly perinuclear distribution of viral particles in the cotyledon cells was evident. After dehydration, when the embryo was dry and mature, degradation of CP did not occur and the perinuclear viral distribution disappeared. Instead, aggregates containing PSbMV CP were found in the cytoplasm. Electron microscopy showed that these aggregates were composed of PSbMV particles. The formation of PSbMV particle aggregates is apparently triggered by seed dehydration and may be favorable to the virus survival in the desiccated embryonic cells.
文摘To study the function and adaptive mechanism of tonoplast H + ATPase under salt stress, pea ( Pisum sativum L.) seedlings were treated with different concentrations of salt (100-250 mmol/L NaCl) and with 100 mmol/L NaCl for different days (1-3 d). The ATP hydrolytic activity and the proton transport activity and the changes of the amount of tonoplast H + ATPase (subunit A) were measured. ATP hydrolytic activity of H + ATPase prepared from plants treated with 250 mmol/L NaCl was reduced by about 25% compared to that of control plants, but that of stressed plants treated with 100 mmol/L and 200 mmol/L NaCl was unchanged. The activity from plants treated with 100 mmol/L NaCl for up to 3 d was lower than that of control plants by 20%. But the proton transport activity was increased under the same salt stresses as above. These results showed that the changes of the hydrolytic activity and the proton transport activity were not in proportion and salt stress may cause the change of the coupling ratio of H + transport activity to ATP hydrolysis. The protein amount kept unchanged and reduced a little only when pea was treated with 100 mmol/L NaCl for 3 d. These results indicated that salinity stimulated the increase of the pump efficiency of the V_ATPase from pea roots, which was due to the change of the coupling ratio, but not due to the increase of ATP hydrolysis and the amount of V_ATPase.
文摘[ Objective] The aim of this study was to discuss the effect of antioxidants and lipid peroxidation from pea crops of plateau. [ Method] SOD enzyme liquid from pea crops of plateau was extracted by means of protein concentration assay, enzyme activity assay and antioxidant activity determination by DPPH method, peroxide activity inhibition of in vitro tissues from mice by homogenate MDA colorimetry method and lipid peroxidation assay of in vitro tissues. [ Result ] IC50 of the crude enzyme liquid extracted from pea on DPPH was 55.16 mg/L, while the scavenging rate of the crude enzyme liquid was lower than that of ascorbic acid, tea polyphenol and citric acid with the same concentration. The synergistic effect was found in ascorbic acid and crude enzyme liquid, but the synergism of ascorbic acid was better than that of citric acid. IC50 of SOD enzyme liquid extracted from pea on DPPH was 11.1 mg/L, which was better than that of tea polyphenol and closely similar to that of ascorbic acid. SOD enzyme liquid extracted from pea had an inhibitory effect on MDA production from in vitro tissues such as liver, kidney and heart, especially for a significantly inhibitory effect on MDA from liver in vitro. When the concentration was 0.25 mg/ml, the inhibition rate reached 78.3%, and then the inhibition rate increased little with the concentration incresas, while its effect on heart and kidney were inferior. [ Conclusion] SOD crude enzyme liquid and SOD enzyme liquid extracted from pea all have certain DPPH scavenging capacity, while SOD enzyme liquid extracted from pea has an inhibitory effect on lipid peroxidation.
