2,4-表油菜素内酯对盐胁迫下黄瓜幼苗叶片光合特性的影响  

Effects of 2,4-epibrassinolide on Photosynthetic Characteristics of Cucumber Seedlings under Salt Stress

作　　者：张帅磊 罗石磊 张文渊 李嘉琪 张国斌[1] ZHANG Shuailei;LUO Shilei;ZHANG Wenyuan;LI Jiaqi;ZHANG Guobin(College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China)

机构地区：[1]甘肃农业大学园艺学院,兰州730070

出　　处：《西北植物学报》2022年第2期272-279,共8页Acta Botanica Boreali-Occidentalia Sinica

基　　金：甘肃省教育厅产业支撑计划项目(2021CYZC-45);甘肃省干旱生境作物学重点实验室主任基金(GHSJ-2020-Z3);国家现代农业产业技术体系专项资金项目(CARS-23-C-07)。

摘　　要：以黄瓜品种’新春4号’为试验材料,研究了在中度盐胁迫(50 mmol/L NaCl)条件下,外源喷施0.01 mg/L 2,4-表油菜素内酯(EBL)和24μmol/L油菜素内酯抑制剂(BZR)处理对盐胁迫下黄瓜幼苗叶片快速叶绿素荧光诱导动力学曲线(OJIP)及相关荧光参数的影响,探讨EBL缓解黄瓜幼苗中度盐胁迫伤害的光合生理机制。结果表明:(1)盐胁迫导致黄瓜幼苗叶片净光合速率(P_(n))、气孔导度(G_(s))、蒸腾速率(T_(r))下降,胞间CO_(2)浓度(C_(i))增加,初始荧光(F_(o))、最大荧光(F_(m))下降,OJIP曲线中J点、I点显著增加,降低了黄瓜幼苗叶片光合性能,且对PSⅡ受体侧的伤害大于供体侧,表现为PSⅡ反应中心损伤,光合电子从Q_(A)向Q_(B)的传递效率降低,电子传递受阻。(2)在50 mmol/L NaCl处理下,外源喷施0.01 mg/L EBL可显著提升NaCl胁迫下黄瓜幼苗叶片P_(n)、G_(s)、T_(r)、光合性能(PI_(ABS)),降低C_(i),显著增加单位面积内吸收(ABS/CS_(m))、捕获(TR_(o)/CS_(m))、用于电子传递(ET_(o)/CS_(m))的光能以及有活性反应中心的数目(RC/CS_(m))。(3)与NaCl+EBL处理相比,NaCl+EBL+BZR处理后黄瓜幼苗叶片光合性能进一步降低,证明EBL对黄瓜幼苗盐胁迫引起的PSⅡ伤害有缓解作用。研究发现,外源喷施适量2,4-表油菜素内酯能有效缓解黄瓜幼苗叶片在盐胁迫条件下受到的光合电子传递链中(PSⅡ)受体侧的伤害,增加电子从Q_(A)向Q_(B)传递的效率,从而显著改善盐胁迫下黄瓜幼苗叶片的光合性能。Taking cucumber cultivar‘Xinchun 4’as experimental material,we studied the effects of exogenous spraying 0.01 mg/L exogenous 2,4-epibrassinolide(EBL)and 24μmol/L brassinolide inhibitor(BZR)on the rapid chlorophyll fluorescence induction kinetics curve(OJIP)and related fluorescence parameters of cucumber seedlings under moderate salt stress(50 mmol/L NaCl),and discussed the photosynthetic physiological mechanism of EBL alleviating the damage of cucumber seedlings under moderate salt stress.The results showed that:(1)salt stress led to the decrease of net photosynthetic rate(P_(n)),stomatal conductance(G_(s))and transpiration rate(T_(r)),the increase of intercellular CO_(2) concentration(C_(i)),the decrease of initial fluorescence(F_(o))and maximum fluorescence(F_(m)),and the increase of J point and I point in the OJIP curve,which reduced the photosynthetic performance of cucumber seedlings,and the damage to PSⅡreceptor side was greater than that on the donor side,showing the damage of PSⅡreaction center.The transfer efficiency of photosynthetic electron from Q_(A) to Q_(B) decreased,and the electron transfer was blocked.(2)Under 50 mmol/L NaCl treatment,exogenous spraying of 0.01 mg/L EBL could significantly improve P_(n),G_(s),T_(r),and photosynthetic performance(PI_(ABS))of cucumber seedlings,reduce C_(i),and significantly increase the absorption per unit area(ABS/CS_(m)),capture(TR_(o)/CS_(m)),light energy for electron transport(ETo/CSm),and the number of active reaction centers(RC/CS_(m)).(3)Compared with NaCl+EBL treatment,the photosynthetic performance of cucumber seedlings after NaCl+EBL+BZR treatment was further reduced,indicating that EBL could alleviate PSⅡdamage caused by salt stress in cucumber seedlings.It was found that exogenous spraying of appropriate amount of 2,4-epibrassinolide could effectively alleviate the damage of(PSⅡ)receptor side of photosynthetic electron transport chain on cucumber seedling leaves,increase the efficiency of electron transfer from Q_(A) to Q_(B),and thus sig

关 键 词：黄瓜 盐胁迫 2 4-表油菜素内脂 叶绿素荧光动力学曲线 光系统Ⅱ(PSⅡ) 

分 类 号：Q945.78[生物学—植物学]