摘要
在自然条件下以分布于兰州九州台(LZJ)、张掖临泽(ZYL)和武威民勤(WWM)3个地区的红砂为试材,利用PAM-2100便携式叶绿素荧光分析仪和Lcpro+便携式光合作用测定系统,在红砂生长季节对其叶绿素荧光参数及其环境因子进行测定和分析。结果表明:3个地区红砂叶片的初始荧光(Fo)、PSⅡ最大光化学量子产量(Fv/Fm)、实际光化学反应量子效率(ΦPSⅡ)和非光化学淬灭系数(qN)均存在明显的日变化。其中Fv/Fm和ΦPSⅡ均呈反正态分布曲线日进程,在中午13:00强光下降低至最低值;Fo和qN则呈正态分布曲线日进程,在中午13:00达到最大值。3个地区红砂的Fv/Fm虽在中午呈降低趋势,但因其值均高于0.8,所以并未发生光抑制现象。在环境因子中,光合有效辐射(PAR)、温度(Ta)以及水分条件协同作用于红砂的光化学效率。当水分条件较高时,PAR成为影响光化学效率降低的首要因子;而当水分降低时,RH成为加速光化学效率下降的主要因子。在土壤极端干旱叠加强光、高温和低湿的逆境中红砂主要采取依赖于叶黄素循环的热耗散和PSⅡ反应中心可逆失活两种保护机制来适应外界环境的变化。
The diurnal change in chlorophyll fluorescence parameters of desert plant Reaumuria soongorica (R. soongorica) that inhabit at Jiuzhoutai of Lanzhou (LZJ), Linze of Zhangye (ZYL), Minqin of Wuwei (WWM) in Gansu Province of China, and the influencing microclimate factors were determined by PAM- 2100 portable chlorophyll fluorometer and Lcpro+ portable photosynthesis analysis system once every hour from 07:00 to 18:00 of the plant's growth season under natural environment. The results showed that minimal fluorescence(Fo ), maximal photochemical efficiency of PS Ⅱ (Fv/Fm), actual photochemistry efficiency( ФPSⅡ) and non-photochemical quenching coefficient( qN ) all exhibited obvious diurnal variation. The diurnal curves of Fv/Fm and ФPSⅡ follow inverse normal distribution, showing the minimum value at 13:00. In contrast, curves of Fo and qN obey normal distribution with the maximum value at 13:00. Although Fv/F,, of R. soongorica in these three areas all declined at midday, there was not the photoinhibition phenomenon because the values of Fv/Fm all were larger than 0.8. Among the environmental factors, photosynthetically active radiation(PAR), air temperature(Ta), and water condition affected photoinhibition in combination. Influence of PAR was significant on photochemical efficiency of PSⅡ when water condition was better, then relative humidity(RH) became the main factor along with the water condition declining. There are two major photoprotective mechanisms that help R. soongorica to survive the adverse circumstances of extreme soil drought coupling with high temperature, strong solar radiation and low air humiditythermal energy dissipation through xanthophyll cycle and the reversible inactivation of PS Ⅱ reaction center.
出处
《中国沙漠》
CSCD
北大核心
2010年第3期539-545,共7页
Journal of Desert Research
基金
国家林业局重点科研项目(2006-35)
甘肃省科技攻关项目(2GS064-A41-003-01)资助
关键词
叶绿素荧光
环境因子
光化学效率
红砂
荒漠植物
chlorophyll fluorescence
environmental factors
photochemical efficiency of PS I]
Reaumuria soongorica
desert plant