不同海拔珠芽蓼叶片类囊体膜色素含量及光系统功能变化

Changes of pigment contents and photosynthetic electron transport activities of thylakoid membranes of Polygonum viviparum grown at different altitudes

以天山3个海拔(2 200,3 400,3 900m)处生长的珠芽蓼叶片为材料,研究了不同海拔珠芽蓼叶片类囊体膜色素含量、叶绿素荧光参数以及光系统电子传递活性的变化。结果表明,不同海拔珠芽蓼叶绿素总含量Chl(a+b)及叶绿素b(Chl b)含量随海拔升高而降低,而叶绿素a/b(Chl a/b),类胡萝卜素/叶绿素(Car/Chl)以及非光化学淬灭系数(NPQ)随海拔升高而增加。Fv/Fm在3 400m处较海拔2 200m处稍有增加,增幅不显著(P>0.05),在海拔3 900m处最低(P<0.05)。Fv/F0在海拔2 200和3 400m处保持稳定,在3 900m处显著降低(P<0.05)。从海拔2 200到3 900m,F734/F686随海拔升高而降低显著(P<0.05)。随海拔升高,PSⅠ、PSⅡ和光合电子传递总链的电子传递活性呈降低趋势。光合总链电子传递活性的降低,主要是由于PSⅠ电子传递活性的下降引起的,尤其是在海拔3 900m。说明在高海拔,PSⅠ较PSⅡ的光抑制程度更严重,低温强辐射所引起的光合电子传递活性降低的主要原因是PSⅠ的光抑制。

The pigment content,chlorophyll fluorescence parameters and photosynthetic electron transport activities of thylakoid membranes were investigated in Polygonum viviparum grown at three different altitudes on the Tianshan Mountains.As altitude increased,the values of Chl（a＋b） and Chl b decreased,while the values of Chl a/b,Car/Chl and NPQ increased.Fv/Fm was slightly higher in the leaves at 3 400 m than that at 2 200 m though the difference was not significant,whereas at 3 900 m,it had the lowest values and was significant（P0.05）.Fv/F0 was stable in leaves at 2 200 and 3 400 m,but at 3 900 m,it became smaller（P0.05）.From 2 200 to 3 900 m,F734/F686 decreased significantly（P0.05）.The activities of PSⅠ,PSⅡ and the whole chain electron transport activity decreased with an increase in altitude.The decrease in the whole chain of photosynthetic electron transport activity was mainly attributable to the decrease in photosynthetic electron transport activity of PSⅠ,especially at 3 900 m.The study revealed that PSⅠ suffered more servere photoinhibition than PSⅡ at higher altitudes,and the decrease in whole chain electron transport activity of leaves exposed to low temperature and strong irradiation was caused mainly by PSⅠ photoinhibition.