嫁接对高温和低温胁迫下辣椒幼苗快速叶绿素荧光诱导动力学特性的影响

Effects of Grafting on the Fast Chlorophyll Fluorescence Induction Dynamics of Pepper Seedlings Under Temperature Stress

以辣椒材料‘P205’和‘野力姆’为砧木,以‘三道筋’为接穗进行嫁接,研究了嫁接对高温(45±1)℃和低温(4±1)℃胁迫下辣椒快速叶绿素荧光诱导动力学特性的影响。结果表明:温度胁迫引起自根苗叶片快速叶绿素荧光诱导曲线(OJIP)发生显著变化,J、I、P相降低明显。JIP-test分析显示,荧光诱导曲线中出现了明显K相,且自根苗和嫁接苗在高温胁迫后的ΔK值均高于低温胁迫,说明辣椒叶片光合机构更易受到高温胁迫的损伤。温度胁迫降低了自根苗和嫁接苗的最大光化学效率(F_v/F_m)、性能指数(PI_(abs)),其中PI_(abs)对温度胁迫更敏感。自根苗和嫁接苗叶片的反应中心单位面积上吸收(ABS/CS_m)、捕获(TR_o/CS_m)和传递(ETo/CS_m)的光能以及反应中心数量(RC/CS_m)在温度逆境中下降,而J相相对可变荧光(VJ)、热耗散量子比率(Ψ_(Do))、单位面积的热耗散(DI_o/CS_m)和综合性能指数(PItotal)升高,其中自根苗所有荧光参数值均与常温对照差异显著。砧木‘P205’嫁接苗和砧木‘野力姆’嫁接苗分别对高温和低温胁迫具有较好的适应性。自根苗和嫁接苗叶片的PI_(total)在温度逆境下均大幅升高,胁迫解除后又迅速恢复,表明在温度胁迫下辣椒叶片光系统Ⅰ(PSⅠ)的受损伤程度较PSⅡ低。

Effects of grafting on the pepper fast chlorophyll fluorescence induction kinetics were studied under high temperature（45 ± 1）℃ and low temperature（4 ± 1）℃ stress in this study. The grafted pepper‘P205＇or‘Yelimu＇was used as a rootstock,and the self-rooted pepper‘Sandaojin＇was used as a scion. Results showed that the fast chlorophyll fluorescence induction curve（OJIP）of self-rooted seedlings had significant changes with a decrease in J,I and P points after heat and chilling stress. JIP-test revealed a significant K phase. Under heat treatment,the ΔK values of self-rooted and grafted seedlings were more than twice higher than those under the chilling stress,indicating that the photosynthetic apparatus of pepper leaves were more susceptible to heat injury. Under heat and chilling stress,the self-rooted seedlings had the greater decrease than those of the grafted seedlings in maximum photochemical efficiency（Fv/Fm）and performance index（PI（abs））. The PIabs was more sensitive to heat and chilling stress than Fv/Fm. For all the tested materials,the phenomenological energy fluxes per excited cross section（ABS/CSm？TRo/CSm and ETo/CSm）and the density of RCs（RC/CSm）were decreased,while the relative variable fluorescence at J-step（VJ）,the dissipated energy flux per CS（DIo/CSm）,the quantum yield for energy dissipation（ΨDo）and the total performance index（PI（total））were increased. All fluorescence parameters of self-rooted seedlings had significant difference compared to the control group. Rootstock‘P205＇and‘Yelimu＇were adaptable for heat and chilling treatment,respectively. The PItotal of grafted and self-rooted pepper increased sharply after high or low temperature stress,followed with a complete recovery at 25 ℃ after 4 h,suggesting that the photosynthetic apparatus of photosystemⅠ（PSⅠ）was less damaged than PSⅡ during the temperature stresses.