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比较研究了‘早美’和‘春蕾’2个早熟桃品种夏季叶色转红对太阳光能的利用和光系统Ⅱ的叶绿素荧光特征的影响。结果表明:早熟桃叶片色素组成的变化会显著影响其光合和叶绿素荧光特性。叶色转红后,早熟桃净光合速率(Pn)日均值、PSⅡ最大光化学效率(Fv/Fm)、PSⅡ实际光化学效率(ФPSⅡ)均上升,无显著光抑制,而绿叶对照‘红花碧桃’的电子传递速率(ETR)、Fv/Fm和ФPSⅡ值均显著下降,7月光合明显受抑制。叶色转红程度较深的‘早美’在夏季高温强光下表现优于‘春蕾’和对照。淬灭分析表明:叶片花色素苷的积累能在短时间内增加PSⅡ天线色素吸收的光能用于光化学反应的份额(P)与用于反应中心热耗散的相对份额(D)。转红后的叶片光化学淬灭系数(qp)显著高于绿叶,PSⅡ光化学效率较高,但耗散过剩激发能的能力显著低于绿叶对照。
A comparative study was conducted on the effects of summer leaf color turning red on the solar energy utilization and the chlorophyll fluorescence characteristics of photosystem Ⅱ in two early-maturing peach cultivars ’Early’ and ’Spring Bud’. The results showed that: the changes of pigment composition of early peach leaf will significantly affect its photosynthetic and chlorophyll fluorescence characteristics. The net photosynthetic rate (Pn), the maximum photochemical efficiency of PSⅡ (Fv / Fm) and the actual photochemical efficiency of PSⅡ (ФPSⅡ) increased with leaf color turning red, Of electron transfer rate (ETR), Fv / Fm and ФPS Ⅱ values were significantly decreased, July photosynthesis was significantly inhibited. Leaf color turn red deeper degree of ’early America’ in the summer under high temperature and high light performance better than ’Chunlei’ and control. Quench analysis showed that the accumulation of anthocyanin in leaf could increase the proportion of photochemical reaction energy (P) and the relative proportion of heat dissipation (D) used in reaction center in a short period of time. The photochemical quenching coefficient (qp) of leaves after turning red was significantly higher than that of green leaves. The photochemical efficiency of PS Ⅱ was higher, but the ability of dissipating excess excitation energy was significantly lower than that of green leaves.