表油菜素内酯对热胁迫下‘美乐’葡萄着色和抗氧化特性的影响

Effects of Epi-brassinolide on Coloration and Antioxidant Characteristic of'Merlot'Grape under Heat Stress

以盆栽2年生酿酒葡萄‘美乐’为试材,在转色前7 d对植株施加50℃高温胁迫,并浸泡5 mg·L-1的24-表油菜素内酯(EBR),以探索EBR缓解热胁迫对葡萄果实上色的影响,以及内源油菜素内酯(BR)合成与果皮花色苷等其他次生代谢产物积累的相关性。结果表明,热胁迫显著延缓了葡萄的转色,降低了果实品质。EBR通过上调花色苷合成及信号转导关键基因的表达,在一定时期内促进了过氧化物酶(POD)等多种抗氧化酶活性和相关基因的表达量,缓解了热胁迫对果皮花色苷积累的抑制作用,减轻了热胁迫对植物细胞膜造成的伤害。综上所述,EBR促进了热胁迫下葡萄果皮的着色,内源BR与葡萄花色苷的合成和多种次级代谢产物的积累密切相关。

Potted two-year-old wine grape'Merlot'was used as test material,the vines were subjected to high temperature stress with 50℃at seven days before version stage,and the vines were simultaneously selected to be soaked in 5 mg·L-1 of 24 Epi-brassinolide(EBR).In this study,the effects of EBR on alleviating heat stress on grape berry color were explored,and the correlation between endogenous BR biosynthesis and the accumulation of anthocyanins or other secondary metabolites in pericarp.The results indicated that heat stress significantly delayed the color change of grape berry and reduced fruit quality.By up-regulating the expression of key genes of anthocyanin synthesis and signal transduction,exogenous EBR promoted the activity of various antioxidant enzymes such as peroxidase(POD)and the expression of related genes in a certain period of time,alleviated the inhibitory effect of heat stress on anthocyanin accumulation in pericarp,and alleviated the damage caused by heat stress on plant cell membrane.In conclusion,EBR promotes the coloration of grape pericarp under heat stress,and endogenous BR is closely related to the synthesis of anthocyanins and the accumulation of multiple secondary metabolites.