外源脱落酸对高温胁迫下菠菜光合与叶绿素荧光参数的影响

Effects of Exogenous Abscisic Acid on the Photosynthesis and Chlorophy Ⅱ Fluorescence Parameters of Spinach under High Temperature Stress

【目的】研究外源脱落酸(Abscisic acid,ABA)对高温胁迫下菠菜叶片净光合速率(Pn)、叶绿素荧光参数与快速光曲线的影响,为菠菜抗高温栽培提供理论依据。【方法】以2个基因型菠菜为试验材料进行高温处理(昼夜温度33℃/27℃,各12 h),适温处理(昼夜温度23℃/17℃,各12 h)作为对照,通过喷施不同浓度ABA(0,5,25,125 mg/L)处理,对不同处理菠菜叶片的光合指标与叶绿素荧光参数进行了测定与比较。【结果】高温处理会显著降低菠菜叶片的P_n、胞间CO_2浓度、气孔导度(Gs)、光系统Ⅱ(PSⅡ)的最大光合效率(F_v/F_m)、PSⅡ的实际光合效率Y(II)、PSⅡ的相对电子传递速率(r ETR)与光化学淬灭(qP),而一定浓度的外源ABA能显著提高高温下两基因型植株叶片的P_n、G_s、F_v/F_m与非光化学淬灭(NPQ)。高温下菠菜叶片潜在最大相对电子传递速率(rETR_(max))与饱和光强较适温均降低,而施用5 mg/L ABA较未施用的rETRmax与饱和光强均显著提高。【结论】高温胁迫导致菠菜叶片光合能力降低,而喷施一定浓度ABA能够缓解高温胁迫对光合器官结构与功能的影响,提高菠菜叶片的光合能力,增强对高温逆境的抵抗力。

【Objective】The effects of exogenous abscisic acid(ABA)on the net photosynthetic rate(Pn),chlorophyII fluorescence parameters and rapid light curves of spinach leaves under high temperaturestress were studied to provide a theoretical basis for its culture resistant to high temperature.【Method】The photosynthetic indexes and chlorophyⅡfluorescence parameters of spinach leaves were determinedand compared under different treatments of high temperature(day and night temperature33℃/27℃,12h each)with concentrations of ABA(0,5,25,125mg/L)using a moderate temperature(day andnight temperature23℃/17℃,12h each)as the control for two genotypes as materials.【Results】Thehigh temperature treatment significantly decreased Pn,intercellular CO2concentration,stomatal conductance(Gs),the maximum photosynthetic efficiency of photosystemⅡ(Fv/Fm),actual photosyntheticefficiency(Y(II)),relative electron transfer rate(rETR)and photochemical quenching(qP).However,acertain concentration of exogenous ABA could significantly increase the Pn,Gs,Fv/Fm and non-photochemical quenching(NPQ)of the leaves of two genotypes under high temperature.The potentialmaximum relative electron transport rate(rETRmax)and the saturation light of spinach leaves weredecreased under high temperature compared with the moderate temperature.The application of5mg/LABA could increase rETRmax and the saturation light compared to those without ABA.【Conclusion】High temperature stress led to a reduction of photosynthetic capacity of spinach leaves.Spraying acertain concentration of exogenous ABA could alleviate the effects of high temperature stress on thestructure and function of photosynthetic organs and increase the photosynthetic capacity of spinachplants and enhance the resistance to high temperature stress.