高温胁迫对高羊茅光合作用的影响

为了解高温胁迫对高羊茅Festuca arundinacea光合作用的影响,以2个高羊茅品种为实验材料,研究高温处理对高羊茅气体交换、叶绿素荧光的影响。结果表明,高温胁迫后,2个高羊茅品种的净光合速率（Pn）均明显下降,其中气孔因素引起了猎狗5号的Pn下降,但并不是交战2号Pn下降的原因。高温胁迫降低了光系统Ⅱ（PSⅡ）最大光化学量子效率（Fv/Fm）、PSⅡ反应中心捕获激发能效率（F′v/F′m）、光化学猝灭（qP）和电子传递速率（RET）,且交战2号的下降幅度较大。但高温胁迫明显增加了高羊茅的非光化学猝灭（qNP）,交战2号的qNP则略低于猎狗5号。2个高羊茅品种均可有效地耗散过剩的激发能,尽可能保护化合机构免受高温胁迫的影响。

High temperature stress with photosynthesis in Festuca arundinacea

To uncover the adaptation mechanisms of photosynthesis for high temperature,gas exchange and chlorophyll fluorescence of Festuca arundinacea cultivars Crossfire 2 and Houndog 5 were tested under control （20 ℃） and high temperature stress （38 ℃） with four replications for net photosynthetic rate （Pn）,stomatal conductance （Gs）,intercellular CO2 concentrations （Ci）,maximum rate of photochemical quantum （Fv /Fm）,efficiency of excitation energy captured by PSⅡ （F′v /F′m）,photochemical quenching （qP）,non-photochemical quenching （qNP）, and electron transport flow （RET）. Results showed that after high temperature stress, Pn in both cuhivars significantly decreased （P〈0.05）, Gs and Ci decreased in ＇Houndog 5＇ , Gs slightly decreased l and Ci even increased in ＇Crossfire 2＇ Fv /F,, F′v/F′m, qP, and RET significantly decreased （P〈0.05） in both cuttivars; and qNP significantly increased（P〈0.05）. These resuits indicated that stomatal factors led to the P, decrease in ＇Houndog 5＇, but non-stomatal factors led to the P, decrease in nacea can protect its ＇Crossfire 2＇ , and that by effectively dissipating extra excitation energy, F. arundiphotosynthetic mechanism from high temperature stress.