[Objective] The aim was to study response of chlorophyll fluorescence parameters in Trifolium repens L.leaves to water stress from perspective of physiology.[Method] With T.repens cultivar ＂Haifa＂ as tested material...[Objective] The aim was to study response of chlorophyll fluorescence parameters in Trifolium repens L.leaves to water stress from perspective of physiology.[Method] With T.repens cultivar ＂Haifa＂ as tested material,three soil water content levels were set to culture plants,including 75% （no stress,CK）,50% （moderate stress,LD） and 25% （severe stress,HD）,the effects of water stress on chlorophyll fluorescence parameters were determined.[Result] The results showed that the chlorophyll fluorescence parameters changed a little when the relative soil moisture content was 75% and 50%,while the chlorophyll fluorescence parameters such as conversion efficiency of primary light energy （Fv/Fm） of PS Ⅱ,the photochemical quenching coefficient （qP） and the quantum yield of PS Ⅱ electron transport （φPS Ⅱ） decreased respectively when the relative soil moisture content was 25%.[Conclusion] When T.repens in severe drought conditions,the physiological functions were damaged,showing symptoms of drought injury.展开更多
Objective:To investigate antibacterial potential of Trifolium alexandrinum(T.alexandrinum) Linn,against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for...Objective:To investigate antibacterial potential of Trifolium alexandrinum(T.alexandrinum) Linn,against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for many tropical diseases.Methods:Non-polar and polar extracts of the leaves of T.alexandrinum i.e.,hexane,dichloromethane(DCM),ethyl acetate(EtOAc), methanol(MeOH) and aqueous(AQ) extracts at five different concentrations(1,2,5,10 and 15 mg/ mL) were prepared to evaluate their antibacterial value.NCCL standards were strictly followed to perform antimicrobial disc susceptibility test using disc diffusion method.Results:Polar extracts demonstrated significant antibacterial activity against tested pathogens.EtOAc and MeOH extracts showed maximum antibacterial activity with higher inhibition zone and were found effective against seventeen of the tested pathogens.While AQ plant extract inhibited the growth of sixteen of the test strains.EtOAc and MeOH plant extracts inhibited the growth of all seven gram positive and ten of the gram negative bacterial strains.Conclusions:The present study strongly confirms the effectiveness of crude leaves extracts against tested human pathogenic bacterial strains causing several tropical diseases.Since Egyptian clover is used as a fodder plant,it could be helpful in controlling various infectious diseases associated with cattle as well.展开更多
AIM： The potential of Trifolium pratense （red clover） extract in the prevention of lipid disorder has attracted increasing attention in recent years. In this study, the aim was to determine whether and how red clov...AIM： The potential of Trifolium pratense （red clover） extract in the prevention of lipid disorder has attracted increasing attention in recent years. In this study, the aim was to determine whether and how red clover extract affected the development of murine diet-induced non-alcoholic steatohepatitis. METHOD： Non-alcoholic steatohepatitis was induced in C57BL/6 mice by feeding mice with a methionine-choline-deficient （MCD） diet. Hematoxylin and eosin staining was used for histological analyses. Real-time PCR was used to analyze the mRNA expression levels. RESULTS： Hepatic steatosis and neeroinflammation was observed in MCD diet-fed mice, and this diet-induced steatosis was sig- nificantly attenuated, whereas liver inflammation was not significantly attenuated, by red clover extract treatment. Consistent with the results of H＆E staining, the MCD diet-induced increase of liver triglycerides and cholesterol levels were significantly reduced by red clover extract treatment. However, with the improvement in hepatic steatosis, mRNA levels of acetyl CoA oxidase, carnitine palrnitoyl transferase-l, and liver fatty acid-binding protein, three genes regulated by peroxisome proliferator-activated receptor （PPAR） ct, were unaffected. CONCLUSION： Red clover extract alleviated MCD diet-induced hepatic steatosis, but did not ameliorate liver inflammation in C57BL/6 mice, and the improvement in hepatic steatosis was not through activating PPAR^t.展开更多
OBJECTIVE:To review beneficial effects of red clover(Trifolium pratense L.)on biological processes.METHODS:A systematic review was carried out according tothe PRISMA checklist.Using Me SH keywords,385 articles were ex...OBJECTIVE:To review beneficial effects of red clover(Trifolium pratense L.)on biological processes.METHODS:A systematic review was carried out according tothe PRISMA checklist.Using Me SH keywords,385 articles were extracted from national and international databases(Pub Med,Science Direct,SID,and Google Scholar search engine)without time limit.After removing duplicates,80 articles were reviewed.RESULTS:Our findings revealed that the compositions of red clover promote anti-oxidant and anti-cancer effects.Furthermore,they exude beneficial effects on cardiovascular functionand improvesymptoms of menopause.Also,these compounds can regulate blood glucose and lipid markers.The effects of the herb on have also been investigated on various tissues including endometrium,breast,skin and reproductive system.CONCLUSION:In recent studies,the anti-cancer effects of clover(Trifolium)extract co-administrated with standard drugs have been reportedin different cancers.展开更多
[Objective] The aim was to select and identify inorganic phosphorus-dissolving bacteria in rhizosphere of Trifolium repens,and to research related effects of growth promotion.[Method] Phosphate solubilizing bacteria i...[Objective] The aim was to select and identify inorganic phosphorus-dissolving bacteria in rhizosphere of Trifolium repens,and to research related effects of growth promotion.[Method] Phosphate solubilizing bacteria in rhizosphere of Trifolium repens in Guizhou Province were separated and selected to determine its ability of phosphate solubilizing and IAA secretion,and growth promotion effect.[Result] Phosphate solubilizing bacteria were multiple and varied in rhizosphere of Trifolium repens;solubilizing quantities of phosphorus from calcium phosphate by RW2,RW6 and RW18 were 337.39,447.45 and 462.03 μg/ml;solubilizing quantity was none of linear relation with organic acid;RW2 proved the one secreted most IAA at 12.69 μg/ml,followed by RW18 at 12.34 μg/ml;the three strains were all of Leclercia sp.,but were of none pathogenicity for seedlings of Trifolium repens,instead,a kind of growth promotion was found.Detailedly,RW18 was most effective in growth promotion for Trifolium repens and plant height,root length and weight,and aboveground biomass increased by 110.98%,9.17%,46.17% and 2% respectively.Hence,RW18 is of great potential.[Conclusion] The research provides scientific references for developing phosphate solubilizing bacteria and compound inoculation and develops a novel way to relieve barren soils,save phosphorus resource,reduce environment pollution,and guarantee sustainable development of agriculture and animal husbandry.展开更多
Three ethylene diurea （EDU） concentrations （0, 150 and 300 mg/L） were used to evaluate the negative impact of ozone （O3） on two cultivars of Trifoliurn repens L. cv. Vardan and Bundel grown under natural field c...Three ethylene diurea （EDU） concentrations （0, 150 and 300 mg/L） were used to evaluate the negative impact of ozone （O3） on two cultivars of Trifoliurn repens L. cv. Vardan and Bundel grown under natural field conditions in a suburban area of Varanasi, India. Mean O3 concentrations varied from 30.3 to 46.6 μg/L during the experimental period. Higher photosynthetic pigments and ascorhic acid concentrations were noticed in both EDU-treated cultivars over non-EDU-treated ones, but a reverse trend was found for lipid peroxidation. Growth parameters and biomass also showed increments under EDU treatment of both cultivars. The ratio of variable fluorescence to maximum fluorescence increased significantly in Vardan but not in Bundel upon EDU treatment. Results revealed that EDU concentration of 300 mg/L was more effective to combat the oxidative stress as well as protecting plants from O3 injury symptoms. The test cultivar Vardan is relatively sensitive to O3, thereby can be used as a bioindicator of O3 pollution in areas having higher O3 concentrations. Results also indicated that Bundel has more efficient antioxidant defense system than Vardan and hence was more tolerant to O3 stress.展开更多
Red clover (Trifolium pratense L.) is a legume forage abundant in phenolic compounds. It tends to brown when cut for hay, due to oxidation of phenolic compounds catalyzed by polyphenol oxidase (PPO), and subsequent bi...Red clover (Trifolium pratense L.) is a legume forage abundant in phenolic compounds. It tends to brown when cut for hay, due to oxidation of phenolic compounds catalyzed by polyphenol oxidase (PPO), and subsequent binding to proteins. Selecting for a greener hay may provide information about the relationship of browning, PPO, and phenolics to each other. The red clover Kenland cultivar was selected over eight breeding cycles for decreased browning after being cut and dried 48 h in the field. Expression of PPO1 and PPO3, in Kenland and three of the eight cycles, was compared by real-time quantitative PCR. Phenolic compounds in Kenland and Cycle 8, collected 0, 24, and 48 h after cutting, were quantified by high-performance liquid chromatography (HPLC). Visual browning scores decreased 12% between Kenland and Cycle 8 (P = 0.02). PPO1 and PPO3 gene expression were not affected by selection. Clovamide decreased 26% in Cycle 8 relative to Kenland (P = 0.016). Sissotrin decreased 10% in Cycle 8 (P = 0.043). Neither total formononetin nor total biochanin A was affected by selection (P = 0.63 and 0.45, respectively). These results suggest that when selecting clover for decreased postharvest browning, a decrease occurs in a phenolic compound that can bind protein independently of PPO. However, PPO1 and PPO3 gene expression, and the major red clover isoflavones, are minimally affected.展开更多
The clovers that comprise Trifolium genus are naturalized in the subtropical and tropical zones in China. They are valuable bioresources as important green manures and pasture grass, which contribute biologically fixe...The clovers that comprise Trifolium genus are naturalized in the subtropical and tropical zones in China. They are valuable bioresources as important green manures and pasture grass, which contribute biologically fixed dinitrogen （N2） and provide nutrition to farming systems. However, there are very few effective strains available for inoculant production and there is little information available about symbiotic rhizobia in Chinese legume clover root nodules. In this study, 139 root nodule bacteria were isolated from two clover species （Trifolium repens and Trifolium pretense） growing in the subtropical and temperate regions of China, 16S rRNA gene sequence analysis, BOX-PCR, whole cell protein SDS-PAGE, and nodulation tests were performed to characterize these strains. The results showed that phenotypic and genetic diversities among 139 isolates were large, with 83 protein patterns and 66 BOX- AIR profiles, respectively. The rhizobial strains were first divided into two large phenotypic protein groups. The sequencing strains representing the two groups were related to Rhizobium leguminosarum USDA2370T and R. sophorae CCBAU03386T and had 99.6%-100% similarities. The phylogeny specificity of the rhizobia from clover was elucidated, while showed a large variation in the fingerprints of the phenotypes and genotypes and genetic diversity was high （revealed by Shannon diversity index, H＇）. The rhizobial isolates from subtropical regions, such as Anhui Province, Yunnan Province and Hubei Province, had higher diversities than those from temperate areas, such as Hebei Province and Shanxi Province, which could be used to identify rhizobial strains from clover and screen efficient inoculum strains. A number of diverse rhizobial strains had been identified and a pool of currently available clover rhizobial strains were increased. This would ultimately increase the likelihood of identifying more efficient strains suited for developing a successful inoculation strategy for the production of white clover.展开更多
A new 5-O-(β-D-glucopyranosyl)-6 -O-benzoyl-2,5-dihydroxybenzoic acid was isolated from the ethyl acetate extract from the whole plants of Trifolium lupinaster L.Its structure was determined and deduced on the basis ...A new 5-O-(β-D-glucopyranosyl)-6 -O-benzoyl-2,5-dihydroxybenzoic acid was isolated from the ethyl acetate extract from the whole plants of Trifolium lupinaster L.Its structure was determined and deduced on the basis of their spectral data.展开更多
The suitability of models for describing the clonal growth of Trifolium repens population was discussed. The results showed that deterministic models were inadequate for describing its clonal growth, but the diffusion...The suitability of models for describing the clonal growth of Trifolium repens population was discussed. The results showed that deterministic models were inadequate for describing its clonal growth, but the diffusion models and the randomwalk models suited for the clonal growth characteristics of the population. And it was found that random-walk models were better than diffusion models for describing a population in an environment with rich natural resources, and the latter was better in a poor environment.展开更多
interactions,many flowers are known to display their attractive qualities,such as scent emission,flower rewards and floral vertical direction,in a rhythmic fashion.However,less is known about how plants regulate the r...interactions,many flowers are known to display their attractive qualities,such as scent emission,flower rewards and floral vertical direction,in a rhythmic fashion.However,less is known about how plants regulate the relationship between these flower traits to adapt to pollinator visiting behavior and increase reproduction success.Here we investigated the adaptive significance of the flower bending from erect to downward in Trifolium repens.We observed the flowering dynamic characteristics(changes of vertical direction of florets,flowering number,pollen grain numbers,pollen viability and stigma receptivity over time after blossom)and the factors affecting the rate of flower bending in T.repens.Then we altered the vertical direction of florets in inflorescence of different types(upright and downward),and compared the pollinator behaviors and female reproductive success.Our results showed that florets opened sequentially in inflorescence,and then bend downwards slowly after flowering.The bending speed of florets was mainly influenced by pollination,and bending angle increased with the prolongation of flowering time,while the pollen germination rate,stigma receptivity and nectar secretion has a rhythm of“lowhigh-low”during the whole period with the time going.The visiting frequency of all the four species of pollinators on upward flowers was significantly higher than that of downward flowers,and they especially prefer to visit flowers with a bending angle of 30°–60°,when the flowers was exactly of the highest flower rewards(nectar secretion and number of pollen grains),stigma receptivity and pollen germination rate.The seed set ratio and fruit set ratio of upward flowers were significantly higher than downward flowers,but significantly lower than unmanipulated flowers.Our results indicated that the T.repens could increase female and male fitness by accurate pollination.The most suitable flower angle saves pollinators’visiting energy and enables them to obtain the highest nectar rewards.This coordination between plants and pollinators maximizes the interests of them,which is a crucial factor in initiating specialized plant-pollinator relationships.展开更多
Starting from sissotrin (1), a natural isoflavonoid isolated from Trifolium baccarinii (Fabaceae), one new semisynthetic derivative, 6-nitrobiochanin A (1b) and two known derivatives, 8-nitrobiochanin A (1a) and 2&quo...Starting from sissotrin (1), a natural isoflavonoid isolated from Trifolium baccarinii (Fabaceae), one new semisynthetic derivative, 6-nitrobiochanin A (1b) and two known derivatives, 8-nitrobiochanin A (1a) and 2",3",4",6"-tetraacetylsissotrin (1c) have been obtained after performing nitration and acetylation reactions. Their structures were assigned after interpretation of their spectrometric (HR-ESI-MS) and spectroscopic (NMR 1D and 2D) data and by comparison with those reported in the literature. The substrate as well as the semisynthetic derivatives were evaluated for their antibacterial activities against six strains. The results reveal that they are inactive or weakly active on the strains tested with the exception of 8-nitrobiochanin A (1a) which showed moderate activity (MIC = 62.5 μg∙mL<sup>−1</sup>) on Staphylococcus aureus ATCC 43300.展开更多
This study presents the volatile constituents from leaves of Trifolium alexandrinum from Pakistan.The dried leaves were subjected to hydrodistillation for extraction and extracted volatile oil was subsequently charact...This study presents the volatile constituents from leaves of Trifolium alexandrinum from Pakistan.The dried leaves were subjected to hydrodistillation for extraction and extracted volatile oil was subsequently characterized by gas chromatography-mass spectrometry technique.A total of 22 compounds were identified where the most dominant constituents were:phytol(46.00%),palmitic acid(9.26%),phytol acetate(6.44%),and linolenic acid(3.47%).Most of these are well-known constituents to exhibit antibacterial,antioxidant,antitumor,and anti-inflammatory activities.展开更多
基金Supported by Doctor Foundation of Shanghai Institute of Technology~~
文摘[Objective] The aim was to study response of chlorophyll fluorescence parameters in Trifolium repens L.leaves to water stress from perspective of physiology.[Method] With T.repens cultivar ＂Haifa＂ as tested material,three soil water content levels were set to culture plants,including 75% （no stress,CK）,50% （moderate stress,LD） and 25% （severe stress,HD）,the effects of water stress on chlorophyll fluorescence parameters were determined.[Result] The results showed that the chlorophyll fluorescence parameters changed a little when the relative soil moisture content was 75% and 50%,while the chlorophyll fluorescence parameters such as conversion efficiency of primary light energy （Fv/Fm） of PS Ⅱ,the photochemical quenching coefficient （qP） and the quantum yield of PS Ⅱ electron transport （φPS Ⅱ） decreased respectively when the relative soil moisture content was 25%.[Conclusion] When T.repens in severe drought conditions,the physiological functions were damaged,showing symptoms of drought injury.
基金financially supported by SERC Fast Track OYSSchem,Department of Science and Technology(DST),New Delhi,India[grant No.304/2004(SR/FT/L-129/2004)]
文摘Objective:To investigate antibacterial potential of Trifolium alexandrinum(T.alexandrinum) Linn,against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for many tropical diseases.Methods:Non-polar and polar extracts of the leaves of T.alexandrinum i.e.,hexane,dichloromethane(DCM),ethyl acetate(EtOAc), methanol(MeOH) and aqueous(AQ) extracts at five different concentrations(1,2,5,10 and 15 mg/ mL) were prepared to evaluate their antibacterial value.NCCL standards were strictly followed to perform antimicrobial disc susceptibility test using disc diffusion method.Results:Polar extracts demonstrated significant antibacterial activity against tested pathogens.EtOAc and MeOH extracts showed maximum antibacterial activity with higher inhibition zone and were found effective against seventeen of the tested pathogens.While AQ plant extract inhibited the growth of sixteen of the test strains.EtOAc and MeOH plant extracts inhibited the growth of all seven gram positive and ten of the gram negative bacterial strains.Conclusions:The present study strongly confirms the effectiveness of crude leaves extracts against tested human pathogenic bacterial strains causing several tropical diseases.Since Egyptian clover is used as a fodder plant,it could be helpful in controlling various infectious diseases associated with cattle as well.
基金supported by the Science and Technology Planning Project of Educational Commission of Fujian Province,China(No.JB12198) and Fujian Province,China(No.2010N0023)
文摘AIM： The potential of Trifolium pratense （red clover） extract in the prevention of lipid disorder has attracted increasing attention in recent years. In this study, the aim was to determine whether and how red clover extract affected the development of murine diet-induced non-alcoholic steatohepatitis. METHOD： Non-alcoholic steatohepatitis was induced in C57BL/6 mice by feeding mice with a methionine-choline-deficient （MCD） diet. Hematoxylin and eosin staining was used for histological analyses. Real-time PCR was used to analyze the mRNA expression levels. RESULTS： Hepatic steatosis and neeroinflammation was observed in MCD diet-fed mice, and this diet-induced steatosis was sig- nificantly attenuated, whereas liver inflammation was not significantly attenuated, by red clover extract treatment. Consistent with the results of H＆E staining, the MCD diet-induced increase of liver triglycerides and cholesterol levels were significantly reduced by red clover extract treatment. However, with the improvement in hepatic steatosis, mRNA levels of acetyl CoA oxidase, carnitine palrnitoyl transferase-l, and liver fatty acid-binding protein, three genes regulated by peroxisome proliferator-activated receptor （PPAR） ct, were unaffected. CONCLUSION： Red clover extract alleviated MCD diet-induced hepatic steatosis, but did not ameliorate liver inflammation in C57BL/6 mice, and the improvement in hepatic steatosis was not through activating PPAR^t.
基金Supported by the Kermanshah University of Medical Science(KUMS)(No.980292)。
文摘OBJECTIVE:To review beneficial effects of red clover(Trifolium pratense L.)on biological processes.METHODS:A systematic review was carried out according tothe PRISMA checklist.Using Me SH keywords,385 articles were extracted from national and international databases(Pub Med,Science Direct,SID,and Google Scholar search engine)without time limit.After removing duplicates,80 articles were reviewed.RESULTS:Our findings revealed that the compositions of red clover promote anti-oxidant and anti-cancer effects.Furthermore,they exude beneficial effects on cardiovascular functionand improvesymptoms of menopause.Also,these compounds can regulate blood glucose and lipid markers.The effects of the herb on have also been investigated on various tissues including endometrium,breast,skin and reproductive system.CONCLUSION:In recent studies,the anti-cancer effects of clover(Trifolium)extract co-administrated with standard drugs have been reportedin different cancers.
基金Supported by Guizhou Program for Agricultural Development([2009]3067)Guizhou Science and Technology Foundation([2012]2199)~~
文摘[Objective] The aim was to select and identify inorganic phosphorus-dissolving bacteria in rhizosphere of Trifolium repens,and to research related effects of growth promotion.[Method] Phosphate solubilizing bacteria in rhizosphere of Trifolium repens in Guizhou Province were separated and selected to determine its ability of phosphate solubilizing and IAA secretion,and growth promotion effect.[Result] Phosphate solubilizing bacteria were multiple and varied in rhizosphere of Trifolium repens;solubilizing quantities of phosphorus from calcium phosphate by RW2,RW6 and RW18 were 337.39,447.45 and 462.03 μg/ml;solubilizing quantity was none of linear relation with organic acid;RW2 proved the one secreted most IAA at 12.69 μg/ml,followed by RW18 at 12.34 μg/ml;the three strains were all of Leclercia sp.,but were of none pathogenicity for seedlings of Trifolium repens,instead,a kind of growth promotion was found.Detailedly,RW18 was most effective in growth promotion for Trifolium repens and plant height,root length and weight,and aboveground biomass increased by 110.98%,9.17%,46.17% and 2% respectively.Hence,RW18 is of great potential.[Conclusion] The research provides scientific references for developing phosphate solubilizing bacteria and compound inoculation and develops a novel way to relieve barren soils,save phosphorus resource,reduce environment pollution,and guarantee sustainable development of agriculture and animal husbandry.
文摘Three ethylene diurea （EDU） concentrations （0, 150 and 300 mg/L） were used to evaluate the negative impact of ozone （O3） on two cultivars of Trifoliurn repens L. cv. Vardan and Bundel grown under natural field conditions in a suburban area of Varanasi, India. Mean O3 concentrations varied from 30.3 to 46.6 μg/L during the experimental period. Higher photosynthetic pigments and ascorhic acid concentrations were noticed in both EDU-treated cultivars over non-EDU-treated ones, but a reverse trend was found for lipid peroxidation. Growth parameters and biomass also showed increments under EDU treatment of both cultivars. The ratio of variable fluorescence to maximum fluorescence increased significantly in Vardan but not in Bundel upon EDU treatment. Results revealed that EDU concentration of 300 mg/L was more effective to combat the oxidative stress as well as protecting plants from O3 injury symptoms. The test cultivar Vardan is relatively sensitive to O3, thereby can be used as a bioindicator of O3 pollution in areas having higher O3 concentrations. Results also indicated that Bundel has more efficient antioxidant defense system than Vardan and hence was more tolerant to O3 stress.
文摘Red clover (Trifolium pratense L.) is a legume forage abundant in phenolic compounds. It tends to brown when cut for hay, due to oxidation of phenolic compounds catalyzed by polyphenol oxidase (PPO), and subsequent binding to proteins. Selecting for a greener hay may provide information about the relationship of browning, PPO, and phenolics to each other. The red clover Kenland cultivar was selected over eight breeding cycles for decreased browning after being cut and dried 48 h in the field. Expression of PPO1 and PPO3, in Kenland and three of the eight cycles, was compared by real-time quantitative PCR. Phenolic compounds in Kenland and Cycle 8, collected 0, 24, and 48 h after cutting, were quantified by high-performance liquid chromatography (HPLC). Visual browning scores decreased 12% between Kenland and Cycle 8 (P = 0.02). PPO1 and PPO3 gene expression were not affected by selection. Clovamide decreased 26% in Cycle 8 relative to Kenland (P = 0.016). Sissotrin decreased 10% in Cycle 8 (P = 0.043). Neither total formononetin nor total biochanin A was affected by selection (P = 0.63 and 0.45, respectively). These results suggest that when selecting clover for decreased postharvest browning, a decrease occurs in a phenolic compound that can bind protein independently of PPO. However, PPO1 and PPO3 gene expression, and the major red clover isoflavones, are minimally affected.
基金Supported by the National Natural Science Foundation of China(30970005,30370051,and 31360003)the Key Bioengineering Discipline of Hebei Province(1050-5030023)+2 种基金the Public Service Sectors(Agriculture)Research and Special Funds(201303061)the Key Discipline Project for Biotechnology of Hebei ProvinceHebei University Construction Project for Comprehensive Strength Promotion of Midwest Colleges and Universities
文摘The clovers that comprise Trifolium genus are naturalized in the subtropical and tropical zones in China. They are valuable bioresources as important green manures and pasture grass, which contribute biologically fixed dinitrogen （N2） and provide nutrition to farming systems. However, there are very few effective strains available for inoculant production and there is little information available about symbiotic rhizobia in Chinese legume clover root nodules. In this study, 139 root nodule bacteria were isolated from two clover species （Trifolium repens and Trifolium pretense） growing in the subtropical and temperate regions of China, 16S rRNA gene sequence analysis, BOX-PCR, whole cell protein SDS-PAGE, and nodulation tests were performed to characterize these strains. The results showed that phenotypic and genetic diversities among 139 isolates were large, with 83 protein patterns and 66 BOX- AIR profiles, respectively. The rhizobial strains were first divided into two large phenotypic protein groups. The sequencing strains representing the two groups were related to Rhizobium leguminosarum USDA2370T and R. sophorae CCBAU03386T and had 99.6%-100% similarities. The phylogeny specificity of the rhizobia from clover was elucidated, while showed a large variation in the fingerprints of the phenotypes and genotypes and genetic diversity was high （revealed by Shannon diversity index, H＇）. The rhizobial isolates from subtropical regions, such as Anhui Province, Yunnan Province and Hubei Province, had higher diversities than those from temperate areas, such as Hebei Province and Shanxi Province, which could be used to identify rhizobial strains from clover and screen efficient inoculum strains. A number of diverse rhizobial strains had been identified and a pool of currently available clover rhizobial strains were increased. This would ultimately increase the likelihood of identifying more efficient strains suited for developing a successful inoculation strategy for the production of white clover.
基金supported by the Overseas Scholars Foundation of Heilongjiang Province Education Department (No.1154h25)Scientific and Technical Agency of Heilongjiang Province Foundation of China(No.LC08C32)
文摘A new 5-O-(β-D-glucopyranosyl)-6 -O-benzoyl-2,5-dihydroxybenzoic acid was isolated from the ethyl acetate extract from the whole plants of Trifolium lupinaster L.Its structure was determined and deduced on the basis of their spectral data.
文摘The suitability of models for describing the clonal growth of Trifolium repens population was discussed. The results showed that deterministic models were inadequate for describing its clonal growth, but the diffusion models and the randomwalk models suited for the clonal growth characteristics of the population. And it was found that random-walk models were better than diffusion models for describing a population in an environment with rich natural resources, and the latter was better in a poor environment.
基金the National Natural Science Foundation of China,Grant Nos.31860051 and 31360044.
文摘interactions,many flowers are known to display their attractive qualities,such as scent emission,flower rewards and floral vertical direction,in a rhythmic fashion.However,less is known about how plants regulate the relationship between these flower traits to adapt to pollinator visiting behavior and increase reproduction success.Here we investigated the adaptive significance of the flower bending from erect to downward in Trifolium repens.We observed the flowering dynamic characteristics(changes of vertical direction of florets,flowering number,pollen grain numbers,pollen viability and stigma receptivity over time after blossom)and the factors affecting the rate of flower bending in T.repens.Then we altered the vertical direction of florets in inflorescence of different types(upright and downward),and compared the pollinator behaviors and female reproductive success.Our results showed that florets opened sequentially in inflorescence,and then bend downwards slowly after flowering.The bending speed of florets was mainly influenced by pollination,and bending angle increased with the prolongation of flowering time,while the pollen germination rate,stigma receptivity and nectar secretion has a rhythm of“lowhigh-low”during the whole period with the time going.The visiting frequency of all the four species of pollinators on upward flowers was significantly higher than that of downward flowers,and they especially prefer to visit flowers with a bending angle of 30°–60°,when the flowers was exactly of the highest flower rewards(nectar secretion and number of pollen grains),stigma receptivity and pollen germination rate.The seed set ratio and fruit set ratio of upward flowers were significantly higher than downward flowers,but significantly lower than unmanipulated flowers.Our results indicated that the T.repens could increase female and male fitness by accurate pollination.The most suitable flower angle saves pollinators’visiting energy and enables them to obtain the highest nectar rewards.This coordination between plants and pollinators maximizes the interests of them,which is a crucial factor in initiating specialized plant-pollinator relationships.
文摘Starting from sissotrin (1), a natural isoflavonoid isolated from Trifolium baccarinii (Fabaceae), one new semisynthetic derivative, 6-nitrobiochanin A (1b) and two known derivatives, 8-nitrobiochanin A (1a) and 2",3",4",6"-tetraacetylsissotrin (1c) have been obtained after performing nitration and acetylation reactions. Their structures were assigned after interpretation of their spectrometric (HR-ESI-MS) and spectroscopic (NMR 1D and 2D) data and by comparison with those reported in the literature. The substrate as well as the semisynthetic derivatives were evaluated for their antibacterial activities against six strains. The results reveal that they are inactive or weakly active on the strains tested with the exception of 8-nitrobiochanin A (1a) which showed moderate activity (MIC = 62.5 μg∙mL<sup>−1</sup>) on Staphylococcus aureus ATCC 43300.
文摘This study presents the volatile constituents from leaves of Trifolium alexandrinum from Pakistan.The dried leaves were subjected to hydrodistillation for extraction and extracted volatile oil was subsequently characterized by gas chromatography-mass spectrometry technique.A total of 22 compounds were identified where the most dominant constituents were:phytol(46.00%),palmitic acid(9.26%),phytol acetate(6.44%),and linolenic acid(3.47%).Most of these are well-known constituents to exhibit antibacterial,antioxidant,antitumor,and anti-inflammatory activities.
