1⁃MCP预处理对杜鹃花高温胁迫下光合特性及相关基因表达的影响  

Effects of 1⁃MCP pretreatment on photosynthetic characteristics and related gene expression of rhododendron seedlings under heat stress

作　　者：王露露 耿兴敏[1] 宦智群 许世达 赵晖 WANG Lulu;GENG Xingmin;HUAN Zhiqun;XU Shida;ZHAO Hui(College of Landscape Architecture,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]南京林业大学风景园林学院,江苏南京210037

出　　处：《南京林业大学学报（自然科学版）》2023年第4期103-113,共11页Journal of Nanjing Forestry University：Natural Sciences Edition

基　　金：江苏高校品牌专业建设工程项目(PPZY2015A063)。

摘　　要：【目的】研究乙烯受体抑制剂1⁃MCP预处理对杜鹃花耐热性及高温胁迫下光合系统的影响,揭示乙烯对杜鹃花耐热性的调控机制。【方法】以两个耐热性不同的杜鹃花属(Rhododendron)品种[‘胭脂蜜’(‘Yanzhi Mi’)和‘红月’(‘Hong Yue’)]为试验材料,分析1⁃MCP预处理对高温胁迫下杜鹃花幼苗热害指数、光合色素含量、光合气体交换参数以及叶绿素荧光参数等的影响,利用‘红月’转录组数据,分析1⁃MCP及高温胁迫对光合通路相关基因的转录调控。【结果】高温胁迫下两个杜鹃花品种叶片的净光合速率(P_(n))、光合色素含量、最大荧光产量(F_(m))、PSⅡ最大光化学效率(F_(v)/F_(o))和潜在的光化学活性(F_(v)/F_(m))下降,初始荧光产量(F_(o))上升,但与‘红月’相比,‘胭脂蜜’中这些指标的变化幅度较小;适宜浓度的1⁃MCP预处理减缓了高温胁迫下杜鹃叶片光合色素含量的下降,使高温胁迫下杜鹃花叶片保持较高的光化学效率,缓解光合机构受到的高温伤害,降低光抑制程度。光合机构比活性参数变化显示,高温胁迫下两个杜鹃花品种叶片单位反应中心吸收的光能[ABS(吸收通量)/RC(反应中心),记为EABS/RC]都显著增加,单位反应中心捕获的用于电子传递的能量(EETo/RC)降低;单位面积光能的吸收、捕获和电子传递的量子产额显著降低,PSⅡ电子传递受阻;适宜浓度的1⁃MCP预处理减缓了两个杜鹃花品种在高温胁迫下单位面积电子传递的量子产额[受光面积,EETo/SSm]、单位面积吸收的光能(EABS/CSm)、单位面积捕获的光能(ETRo/CSm)的下降,通过增加单位反应中心电子传递,减轻电子传递链过度还原,以缓解PSⅡ反应中心电子传递受阻程度。‘红月’转录组数据分析结果显示,高温胁迫下光合通路相关基因,除psbA外,其余30个DEGs都下调表达,而1⁃MCP预处理在一定程度上缓解了部分与光合通路相关�【Objective】Our goals are to reveal regulatory mechanisms of ethylene on the heat tolerance of rhododendron seedlings,and to examine the effects of ethylene receptor inhibitor 1⁃MCP pretreatment on the heat tolerance and the photosynthetic system of rhododendron seedlings under high temperature stress.【Method】Two Rhododendron cultivars with different heat resistance were used to analyze the effects of 1⁃MCP pretreatment on the heat damage index,photosynthetic pigment content,photosynthetic gas exchange parameters and chlorophyll fluorescence parameters of rhododendron leaves under high temperature stress.Furthermore,the transcriptome data of‘Hong Yue’were used to analyze the transcriptional regulation of 1⁃MCP pretreatment and high temperature stress on the related photosynthetic pathway genes.【Results】High temperature stress reduced net photosynthetic rate(P_(n)),photosynthetic pigment content,fluorescence maximum(F_(m)),potential photochemical activity(F_(v)/F_(o))and maximal photochemical efficiency(F_(v)/F_(m)),whereas it increased fluorescence origin(F_(o))in the two Rhododendron cultivars.However,the change ranges of these indexes were smaller in‘Yanzhi Mi’than in‘Hong Yue’.The pretreatment with appropriate concentrations of 1⁃MCP slowed down the decline of chlorophyll content under high temperature stress,maintained the stability of relevant indexes of photosynthetic system of rhododendron leaves,alleviated the damage of photosynthetic apparatus induced by heat stress,and reduced the degree of photoinhibition.Changes of the parameters of the PSⅡreaction center activity showed that the absorption flux per reaction center(ABS/RC)increased significantly in the leaves of the two Rhododendron cultivars,while the rate of electron transport flux of the photosystemⅡreaction center(ETo/RC)decreased under high temperature stress.The quantum yield of light energy absorption,capture and electron transfer per unit area decreased significantly,suggesting that the electron transfer of t

关 键 词：杜鹃花 高温胁迫 乙烯受体抑制剂 光合作用 差异表达基因 

分 类 号：S685.21[农业科学—观赏园艺]