干旱及复水对不同种源河北木蓝气孔结构与内源激素等生理特征的影响OA

The aim of this study was to quantify and compare the physiological and biochemical responses between wild and cultivated Indigofera bungeana lines under drought stress and rehydration.Wild and cultivated varieties of I.bungeana were subjected to a progressive drought stress treatment for 3,6,10 and 13 days,imposed by controlling the water level in pots,followed by rehydration for 2 and 7 days.We conducted a comparative analysis based on multiple physiological and biochemical indicators,including biomass accumulation,stomatal morphology,leaf relative water content(RWC),cell membrane stability,antioxidant indexes[catalase(CAT)activity and hydrogen peroxide(H2O2)content],and the contents of endogenous hormones[auxin(IAA),ethylene(ETH),abscisic acid(ABA)].The main results were as follows:1)Under drought stress,compared with CK,the total biomass,stomatal density and aperture,leaf RWC,and ETH content decreased,whereas leaf relative electrical conductivity(REC),CAT activity,and IAA and ABA contents increased.Under drought stress,total chlorophyll and leaf H2O2 contents decreased in the wild variety,while root H2O2 contents increased.In contrast,both total chlorophyll and H2O2 contents increased under drought stress in the cultivated variety.2)After rehydration,all indexes gradually returned to the control level,indicating that the plants were capable of compensatory growth after drought.3)Correlation analyses revealed extremely significant positive correlations(P<0.01)between stomatal density and leaf RWC,chlorophyll content,H2O2 content,hormone contents,REC,and CAT activity in the two varieties of I.bungeana.In a principal component analysis,the first principal component(PC1)accounted for 57.6%of the variance,and was predominantly characterized by high loadings of ABA,IAA,H2O2 contents,and stomatal aperture;the second principal component(PC2)explained 20.9%of the variance,and was mainly associated with leaf RWC and CAT activity.These results show that both varieties of I.bungeana reduced the rate of water loss under drought stress by regulating stomatal structure,activating their antioxidant defense system and endogenous hormone signaling pathways and maintaining membrane stability,as resistance responses to drought stress.Of the tested varieties,the cultivated variety showed more significant responses of the various indexes to drought stress,demonstrating stronger drought adaptability.