利用叶绿素荧光技术分析2个草莓品种的低温适应性

利用快速叶绿素荧光诱导动力学曲线分析技术及JIP-test分析,研究了4℃低温胁迫1、2、4、6 d对一季草莓‘红颜’和四季草莓‘圣安德瑞斯’光系统Ⅱ的影响,结合相对电导率和叶绿素含量分析2个草莓品种的低温适应性。结果表明:胁迫条件下K相可变荧光占F_J-F_o振幅的比例(W_k)无显著增加,PSII放氧复合体未受到伤害;但随低温胁迫时间延长2个草莓品种最大光化学效率(F_v/F_m)及性能指数(PI_abs)降低,发生光抑制;同时用于电子传递到Q^-_A以下的效率(ψ_o)和电子传递的量子比率(φ_Eo)也在降低;反应中心的数量(RC/CS_o),反应中心吸收、捕获的能量(ABS/RC、TR_o/RC)随胁迫时间延长大致呈增加趋势,但低于各自对照;‘圣安德瑞斯’虽在胁迫后期反应中心吸收的光能(ABS/RC)较‘红颜’多,但没有更多用于推动电子传递(ET_o/RC),而是通过热耗散(DI_o/RC)减轻对植株的伤害,相反‘红颜’反应中心数量增加后吸收的能量多用于推动电子传递;4℃低温下,2个草莓品种质膜透性相对稳定;与各自对照相比,‘红颜’叶片的各参数在低温胁迫后变化幅度缓于‘圣安德瑞斯’。快速叶绿素荧光动力学参数、相对电导率和叶绿素含量的比较结果显示,‘红颜’对低温的适应性优于‘圣安德瑞斯’。

Studies on low temperature adaptability of two strawberries cultivars by chlorophyll fluorescence technology

The effects of 4℃low temperature stress(1 d,2 d,4 d and 6 d)on the photosystemⅡof‘Benihoppe’and‘San Andreas’were studied by using the fast chlorophyll fluorescence induction dynamics curve analysis and JIP-test,that the low temperature adaptability of two strawberry varieties was analyzed by combining the relative conductivity and chlorophyll content.The results showed that there was no significant increase of the ratio of K-phase variable fluorescence to F_J-F_Oamplitude(W_k)under stress,indicating that the oxygen releasing complex was not damaged.But the maximum photochemical efficiency(F_v/F_m)and performance index(PI_abs)of two strawberry cultivars decreased with the prolongation of low temperature stress,and photoinhibition occurred,while the efficiency of electron transfer to below Q^-_Aand the quantum ratio of electron transfer(ψ_o)and electron transfer(φ_Eo)were decreased with the prolongation of stress time.The number of reaction centers(RC/CS_o),and the energy absorbed and captured by the unit reaction center(ABS/RC,TR_o/RC)increased with the prolongation of stress time,but it was lower than the control,although‘San Andreas’absorbed more light energy(ABS/RC)in the reaction center at the later stage of stress than‘Benihoppe’,it was not more used for ER_o/RC,but reduced the damage to the plant through heat dissipation(DI_o/RC),on the contrary‘Benihoppe’,the absorbed energy was mostly used to promote electron transfer when the number of reaction centers increased.The plasma membrane permeability of the two strawberry varieties was relatively stable at 4℃.Compared with the control,the variation of the parameters of‘Benihoppe’was slower than that of‘San Andreas’after low temperature stress.According to the comparison results of chlorophyll fluorescence parameters and relative conductivity and chlorophyll content,it can be preliminary determined that the adaptability of strawberry cultivar‘Benihoppe’to low temperature is better than that of cultivar‘San Andreas’.