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以牡丹‘肉芙蓉’离体叶片为试材,以25℃为对照,研究了强光(1400μmol·m-2·s-1)下高温(40℃)和低温(15℃)处理对牡丹叶片PSⅡ光化学活性和生理特性的影响.结果表明:随处理时间的延长,各处理叶片的PSⅡ最大光化学效率(Fv/Fm)、PSⅡ实际光量子效率(ΦPSⅡ)和光下开放的PSⅡ反应中心激发能捕获效率(Fv’/Fm’)均持续降低.暗恢复4h后,对照和15℃处理叶片的Fv/Fm基本上完全恢复,而40℃处理叶片仅恢复到处理前的75.5%,即使15h后也不能完全恢复;强光下40℃处理使PSⅠ和PSⅡ间的激发能分配严重偏离平衡状态.强光下40℃处理抑制了超氧化物歧化酶活性,加剧了O2·-、H2O2、丙二醛的产生,导致叶绿素和可溶性蛋白含量不断下降.说明强光下40℃高温胁迫对牡丹叶片光合机构造成了不可逆的破坏,而15℃低温处理对其光合机构的影响相对较弱.
Taking the leaves of Peony ’hibiscus’ as test material, the effects of high temperature (40 ℃) and low temperature (15 ℃) under high light (1400μmol · m-2 · s-1) PSⅡ photochemical activity and physiological characteristics were studied.The results showed that the maximum photochemical efficiency of PSⅡ (Fv / Fm), PSⅡ actual photon efficiency (ΦPSⅡ) and the PSⅡ reaction center excitation energy capture efficiency (Fv ’/ Fm’) decreased continuously.After 4 h of dark recovery, the Fv / Fm of the control and 15 ℃ treated leaves were almost completely restored, while the leaves treated at 40 ℃ recovered only 75.5% of the untreated leaves, even after 15h And completely recovered.The intensity of excitation energy distribution between PSⅠ and PSⅡ seriously deviated from equilibrium after 40 ℃ treatment under high light.The activity of superoxide dismutase (SOD) was inhibited by 40 ℃ in the light, exacerbated by O2 · -, H2O2, malondialdehyde Resulting in the continuous decline of chlorophyll and soluble protein content, indicating that 40 ℃ under high light stress caused irreversible damage to the photosynthetic apparatus of leaves, while 15 ℃ low temperature treatment on its photosynthetic institutions relatively weak.