表油菜素内酯对干旱胁迫条件下黄瓜幼苗的影响

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中图分类号：S642.2 文献标志码：A 文章编号：1673-2871（2025）11-077-08

Abstract：Droughtisoneofthemajorabioticstressesaffectingplant growthanddevelopment.Thisstudyaims toinvestigatetheeffctsof exogenous2，4-epibrassnolide（EBR）onthe growth，physiologicalcharacteristicsantioxidantdefense system，and key genes inthe MAPK cascade response of cucumber seedlings under droughtstress.Thecucumber variety Jinyou 186 wasused as the experimental material，and four treatments were setup：Distiled water spraying（CK）， 50mmol⋅L-1 PEG（PEG）， 50mmol⋅L-1PEG+0.02mmol⋅L-1 EBR spraying（PEG+EBR），and 50mmol⋅L-1PEG+ 24mmol⋅L-1 brassinosteroid biosynthesis inhibitor spraying（PEG + BRZ）.The results showed that compared with the PEG treatment，the PEG + EBR treatment significantly increased the plant height， fresh mass of the aboveground part， fresh mass of theundergroundpart，totalroot length，total root surfacearea，and totalchlorophyllcontentof cucumber seedlingsafter 48h of treatment. At 24h of treatment， compared with the PEG treatment，the PEG+EBR treatment significantlyincreasedtheactivityofcatalase by 27.86% and decreased theactivityof peroxidase by 41.58% ，while the content ofsolublesugarand prolineweresignificantlyincreasedby 51.47% and 30.69% ，respectively，andtherelativeconductivity was significantly decreased by 22.22% . Inaddition，EBR induced the up-regulation of the expression of CsMAPK6 and CsMAPK9 genes inthe MAPKcascade signaling pathway，thereby enhancing thedrought tolerance ofcucumber.Insummary，exogenous EBRapplicationcanefectivelyalleviate thedamageofdroughtstresstocucumberseedings byenhancingantioxidantcapacityandactivatingdrought-related signalingpathways，and promotethegrowthandroot system development of cucumber seedlings.Theresults of this study provide a theoretical basis for theuseof exogenous EBR to improve the drought tolerance of cucumber seedlings.

Key Words：Cucumber; Drought Stress; Epibrassinolide; Antioxidant;MAPK

黄瓜（CucumissativusL.）作为一种经济价值高且营养丰富的蔬菜，在世界各地广泛种植。（剩余12632字）