光质对番茄果实表面光系统活性的影响

以保罗塔番茄果实为试材,采用叶绿素成像荧光仪(MINI-IMAGING-PAM)测试分析了蓝(453±2)nm、绿(519±2)nm、红(623±2)nm 3种光质对番茄果实表面光化学活性的影响。结果表明:随着光强的增加(200～2 500μmol/(m.2s)),蓝光和红光处理番茄果实表面光系统Ⅱ(PSII)最大光化学量子产量Fv/Fm、PSII实际量子产量Y(Ⅱ)、电子传递速率ETR和PSII天线转化效率Fv’/Fm’均呈"S"型下降趋势;光系统间激发能分配不平衡偏离系数β/α-1急剧上升,反映出高光强导致光系统间激发能分配的不平衡,PSⅡ和PSⅠ间线性电子传递的协调性降低;而绿光处理番茄果实表面叶绿素荧光参数相对来说变化不大,可能是绿光减少了叶绿素对光能的过度吸收,使得光抑制程度较轻;蓝光处理番茄果实表面Fv/Fm、Y(Ⅱ)、ETR和Fv’/Fm’均小于红光和绿光处理,并且随着光强的增加这种差距越来越明显,表明蓝光对光抑制更敏感,更容易受到强光胁迫的影响;另外,当光强为200～1 000μmol/(m.2s)时,番茄果实表面Fv/Fm、Y(Ⅱ)和Fv’/Fm’值红光>绿光,超过1 000μmol/(m.2s)时,则绿光>红光,反映出绿光处理番茄果实适应强光的能力较强。

Effects of Light Quality on the Photosystem Activity of Tomato Fruit Surface

The effect of light quality on the photochemical activity of tomato fruit surface was studied by a MINI-IMAGING-PAM system.The results showed that as the intensity of light quality rises(200-2 500 μmol/(m2 · s)),the maximal photochemical efficiency(Fv/Fm),the effective PS II quantum yield(Y(II)),the apparent electron transport rate(ETR)and the open PSII reaction centers(Fv′/Fm′)of tomato fruit surface which was under red light and blue light treatments all decreased in the shape of "S",while the relative deviation(β/α-1)from full balance between two photosystems rised gradually,indicating that excitation energy high intensity has broken the balance of excitation energy distribution between PSII and PSI,thus leading to the poorer cooperation of two photosystems.Chlorophyll fluorescence of tomato fruit surface which was under green light treatments was proved to be feasible,showing that green light may reduce the chlorophyll to absorb excessive of light energy and decrease photoinhibition.Fv/Fm、Y(Ⅱ)、ETR and Fv′/Fm′ of tomato fruit surface which was under blue light was smaller than red light and blue light,these gaps will widen with an increase in intensity,which indicated blue light was sensitive to photoinhibition.In case of lower light intensity(200-1 000 μmol/(m2 · s)),Fv/Fm、Y(Ⅱ)and Fv′/Fm′ of tomato fruit surface which was under red light was higher than green light,while over 1 000 μmol/(m2 · s) leading to reverse results,which showed that the capacity of adapting to high light intensity of tomato fruit surface which was under green light was strong.