Dichondra(Dichondra repens)is an important ground cover plant and is also used as a herbal medicine in China.Objectives of this study were to evaluate phenotypic and genetic diversities among 33 genotypes by using 18 ...Dichondra(Dichondra repens)is an important ground cover plant and is also used as a herbal medicine in China.Objectives of this study were to evaluate phenotypic and genetic diversities among 33 genotypes by using 18 simple sequence repeat(SSR)markers and to further identify the drought tolerance of these germplasms based on five physiological parameters.Results showed that natural variations in phenotypes including plant height,leaf area,leaf thickness,and petiole length were observed among 33 genotypes under well-watered conditions.All 18 SSR primer pairs were found to be polymorphic and significant genetic variation was found in these genotypes.In addition,there were obvious differences in leaf relative water content(RWC),electrolyte leakage(EL),chlorophyll(Chl)content,photochemical efficiency(Fv/Fm),and performance index on absorption basis(PIABS)among 33 genotypes in response to a prolonged period of drought stress(46 d).Drought tolerance of 33 genotypes was then ranked by using subordinate function value analysis(SFVA)and the most drought-tolerant or-sensitive genotypes were identified as Dr5 or Dr29,respectively.Principal component analysis(PCA)further classified 33 genotypes into group I(drought-tolerant),group II(droughtsensitive),and group III(medium types).Current findings showed that 18 selected SSR primers could be potentially used to analyze genetic diversity and varietal identification in dichondra species.Drought-tolerant wild dichondra resources provide a rich genetic base for breeding of new cultivars.展开更多
γ-Aminobutyric acid(GABA)is known for its positive effects on improving plant stress tolerance,while the association of its role in regulating nutritional availability and GABA priming-enhanced heat tolerance is not ...γ-Aminobutyric acid(GABA)is known for its positive effects on improving plant stress tolerance,while the association of its role in regulating nutritional availability and GABA priming-enhanced heat tolerance is not well documented.The objective of this study was to determine whether GABA priming may improve heat tolerance in cool-season grass species involving regulation of plant nutrition for macronutrients and micronutrient elements.Plants of creeping bentgrass(Agrostis stolonifera)(cv.'Penncross')in each pot were treated with 10 mL of water(control)or 0.5 mM GABA(GABA priming)by foliar spray and then subjected to heat stress(35/30°C,day/night)or optimal growth temperature(control)(21/19°C,day/night)(non-stress control)for 30 d in growth chambers.GABA-primed plants had significantly higher endogenous GABA content associated with improved heat tolerance compared to non-treated plants,as reflected by higher leaf cell membrane stability,relative water content,osmotic adjustment,chlorophyll content,photochemical efficiency,and net photosynthetic rate.Plants pretreated with GABA exhibited significantly higher content of nitrogen(N),phosphorus(P),calcium(Ca),sodium(Na),and copper(Cu)but lower content of boron(B)and manganese(Mn)in leaves than non-treated plants under heat stress.The enhanced accumulation of N,P,Ca,Na,and Cu and restricted B and Mn accumulation by GABA priming indicate that GABA could modulate mineral nutrient availability in plants,contributing to improved heat tolerance for creeping bentgrass.展开更多
文摘Dichondra(Dichondra repens)is an important ground cover plant and is also used as a herbal medicine in China.Objectives of this study were to evaluate phenotypic and genetic diversities among 33 genotypes by using 18 simple sequence repeat(SSR)markers and to further identify the drought tolerance of these germplasms based on five physiological parameters.Results showed that natural variations in phenotypes including plant height,leaf area,leaf thickness,and petiole length were observed among 33 genotypes under well-watered conditions.All 18 SSR primer pairs were found to be polymorphic and significant genetic variation was found in these genotypes.In addition,there were obvious differences in leaf relative water content(RWC),electrolyte leakage(EL),chlorophyll(Chl)content,photochemical efficiency(Fv/Fm),and performance index on absorption basis(PIABS)among 33 genotypes in response to a prolonged period of drought stress(46 d).Drought tolerance of 33 genotypes was then ranked by using subordinate function value analysis(SFVA)and the most drought-tolerant or-sensitive genotypes were identified as Dr5 or Dr29,respectively.Principal component analysis(PCA)further classified 33 genotypes into group I(drought-tolerant),group II(droughtsensitive),and group III(medium types).Current findings showed that 18 selected SSR primers could be potentially used to analyze genetic diversity and varietal identification in dichondra species.Drought-tolerant wild dichondra resources provide a rich genetic base for breeding of new cultivars.
文摘γ-Aminobutyric acid(GABA)is known for its positive effects on improving plant stress tolerance,while the association of its role in regulating nutritional availability and GABA priming-enhanced heat tolerance is not well documented.The objective of this study was to determine whether GABA priming may improve heat tolerance in cool-season grass species involving regulation of plant nutrition for macronutrients and micronutrient elements.Plants of creeping bentgrass(Agrostis stolonifera)(cv.'Penncross')in each pot were treated with 10 mL of water(control)or 0.5 mM GABA(GABA priming)by foliar spray and then subjected to heat stress(35/30°C,day/night)or optimal growth temperature(control)(21/19°C,day/night)(non-stress control)for 30 d in growth chambers.GABA-primed plants had significantly higher endogenous GABA content associated with improved heat tolerance compared to non-treated plants,as reflected by higher leaf cell membrane stability,relative water content,osmotic adjustment,chlorophyll content,photochemical efficiency,and net photosynthetic rate.Plants pretreated with GABA exhibited significantly higher content of nitrogen(N),phosphorus(P),calcium(Ca),sodium(Na),and copper(Cu)but lower content of boron(B)and manganese(Mn)in leaves than non-treated plants under heat stress.The enhanced accumulation of N,P,Ca,Na,and Cu and restricted B and Mn accumulation by GABA priming indicate that GABA could modulate mineral nutrient availability in plants,contributing to improved heat tolerance for creeping bentgrass.
