ABA与EBR对水分胁迫下葡萄幼苗叶绿素荧光和抗氧化酶活性的调节

Regulation of chlorophyll fluorescence and antioxidant enzymes of grape seedlings by ABA and EBR under water stress

【目的】探讨脱落酸(abscisic acid,ABA)在24-表油菜素内酯(24-epibrassinolide,EBR)调节水分胁迫下葡萄幼苗光系统Ⅱ和抗氧化酶活性中的作用。【方法】以酿酒葡萄品种赤霞珠2年生盆栽扦插苗为研究对象,待幼苗长至10~12片真叶时,将其移栽至含1/2Hoagland营养液水培盆中进行培养,用EBR、ABA以及去甲二氢化愈创木酸(ABA合成抑制剂,NDGA)预处理赤霞珠幼苗,以终质量分数为10%的PEG6000模拟水分胁迫,设5个处理,分别为:CK1(正常生长,葡萄幼苗未经激素和水分胁迫处理),CK2(水分胁迫处理),EBR+PEG(0.1mg/L EBR+水分胁迫处理),ABA+PEG(20 mg/L ABA+水分胁迫处理),EBR+NDGA+PEG(0.1 mg/L EBR+2.95 mg/L NDGA+水分胁迫处理),研究不同处理葡萄幼苗的叶绿素含量、光系统Ⅱ参数、抗氧化酶活性及活性氧代谢情况。【结果】与CK1相比,水分胁迫引起赤霞珠幼苗叶绿素含量下降以及超氧阴离子自由基(O-·2)和丙二醛(MDA)积累。EBR+PEG、ABA+PEG和EBR+NDGA+PEG处理均能够缓解水分胁迫造成的叶绿素含量损失,提高光系统的最大光化学量子产量(Fv/Fm)、有效光化学量子产量(ФPSⅡ)、非光化学淬灭系数(NPQ),降低最小初始荧光(F0),减轻葡萄叶片的光抑制程度;同时提高超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)的活性,降低O-·2和MDA含量,使幼苗抗旱能力增强。【结论】ABA参与调控EBR对植株的缓解效应,但它不是限制EBR发挥作用的主要因素。

【Objective】This study investigated the effect of abscisic acid（ABA）and 24-epibrassinolide（EBR）on grape seedlings under water stress.【Method】Two-year-old Cabernet Sauvignon seedlings planted in pots were transported into 1/2Hoagland solutions when 10-12 true leaves grew out.The seedlings were subjected to mass fraction 10% PEG6000 after being treated with EBR,ABA,and NDGA.Five treatments included CK1（naturally growing）,CK2（water-stressed）,EBR＋PEG（0.1 mg/L EBR＋ waterstressed）,ABA＋PEG（20 mg/L ABA＋ water-stressed）,and EBR＋NDGA＋PEG（0.1 mg/L EBR＋2.95mg/L NDGA＋water-stressed）.The effects of different treatments on photosynthesis characters,reactive oxygen metabolism,and antioxidant enzymes were then studied.【Result】Compared to CK1,waterstress resulted in decrease of chlorophyll and caused increase of superoxide anion（O-·2）and malonaldehyde（MDA）contents in CS seedlings.PGRs applications ameliorated chlorophyll degradation and increased chlorophyll fluorescence parameters such as Fv/Fm,ФPSⅡand NPQ,while decreased F0.They also significantly increased activities of antioxidant enzymes（SOD,CAT,and POD）and decreased levels of O-·2and MDA,which made the grapevines more drought resistant.【Conclusion】ABA was involved in the alleviation of adverse effect due to water stress by EBR in grape seedlings.However,it was not the most significant factor.