EBR预处理对盐胁迫下葡萄幼苗叶片抗氧化物质及酶活性的影响

Effects of EBR Pretreatment on Antioxidant Substances and Enzyme Activities of Grapevine Seedling Leaves under Salt Stress

以2年生葡萄(Vitis vinifera L.)酿酒品种赤霞珠扦插苗为材料,在水培条件下,分别用0、0.05、0.10和0.20mg/L 24-表油菜素内酯(EBR)预处理幼苗,然后进行50mmol/L NaCl胁迫,分别在胁迫6d和12d测定幼苗叶片中超氧阴离子(O_2~)、丙二醛(MDA)、抗氧化物质含量以及相关酶活性,探讨EBR预处理对葡萄幼苗耐盐性的影响。结果表明:与单独盐胁迫处理相比,不同浓度的EBR预处理使盐胁迫葡萄幼苗叶片O_2~和MDA含量显著降低,同时使其抗氧化物质抗坏血酸(AsA)、脱氢抗坏血酸(DHA)、还原型谷胱甘肽(GSH)和氧化型谷胱甘肽(GSSG)含量以及抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)、超氧化物歧化酶(SOD)活性显著升高;其中,0.10mg/L EBR预处理的表现最佳,在盐胁迫12d时,其葡萄叶O_2~和MDA含量比单独盐胁迫处理分别显著降低30.5%和22.0%,其叶片相应AsA和GSH的含量较单独盐胁迫处理分别显著提高82.8%和27.9%,且GR、APX和SOD活性分别显著提高7.2%、8.5%和24.0%。研究发现,在盐胁迫条件下,适宜浓度的外源BRs预处理能够显著降低葡萄叶片中活性氧含量,提高抗氧化物质含量和抗氧化酶活性,以促进AsA-GSH循环的快速有效运转,有效减轻植株的过氧化伤害,缓解盐胁迫对葡萄幼苗的伤害,提高葡萄的耐盐性。

The2-year-old Vitis vinifera grape seedlings were cultured in nutrient solution and pretreated with0,0.05,0.10and0.20mg/L of exogenous24-Epibrassinolide(EBR),respectively,and then stressed with50mmol/L NaCl.The content of superoxide anion(O-·2),malondialdehyde(MDA),antioxidants and the activities of related enzymes in the seedling leaves were measured at6and12days after salt stress,respectively.This study was conducted to determine the influence of EBR pretreatment on antioxidant substances and enzyme activities of grapevine seedling leaves under salt stress.The results showed that compared with the salt stress alone,the EBR pretreatment at different concentrations decreased the contents of O-·2and MDA significantly in the grape leaves,as well as,the contents of ascorbate(AsA),dehydroascorbic acid(DHA),reduced glutathione(GSH)and oxidized glutathione(GSSG).In addition,the EBR pretreatment significantly increased the activities of ascorbate peroxidase(APX),glutathione reductase(GR)and superoxide dismutase(SOD).Among these treatments0.10mg/L EBR pretreatment showed the best performance.Compared with the salt stress alone,after salt treated for12days,the0.10mg/L EBR pretreatment decreased the contents of O-·2and MDA by30.5%and22.0%,significantly increased the contents of AsA and GSH by82.8%and27.9%,improved the activities of GR,APX and SOD by7.2%,8.5%and24.0%,respectively.The results showed that exogenous BRs pretreatment reduced the content of reactive oxygen and increased the contents of antioxidant substances and activities of enzymes through promoting the ascorbate-glutathione(AsA-GSH)cycle.Meanwhile,BRs pretreatment reduced the oxidative damage and mitigated the effects of grape seedling leaves in salt stress,enhancing the tolerance of grape seedling to salt stress.