金叶女贞遮阴复绿过程中光系统Ⅱ功能转变研究

Transformation of photosystem Ⅱ function during greening in golden leaves of Ligustrum vicaryi

金叶女贞的阳生金叶经遮阴后可以复绿。借助调制式与非调制式2种叶绿素荧光仪,探测了该生物学现象中叶片光系统Ⅱ(PSⅡ)生理功能的转变过程。结果表明:遮阴处理前,阳生金叶Fv/Fm、F0均比阴生绿叶低;阳生金叶OJIP的P峰实际强度显著低于阴生绿叶,而OP双重标准化后阳生金叶J相的相对强度强于阴生绿叶。遮阴处理后,金叶逐渐变绿,荧光参数变化表明PSⅡ生理功能分两阶段恢复:2周前,F0增加,而Fv/Fm降低;2周后,F0减小,而Fv/Fm增加。经过2个月的遮阴处理,阳生金叶的F0、Fv/Fm以及OJIP均恢复到了阴生绿叶的水平。自然光照条件下,金叶女贞叶片上大部分PSⅡ单元受到光胁迫而失活,而剩余有活性的PSⅡ反应中心的受体侧的相对活性较低;遮阴处理后,阳生金叶的PSⅡ天线系统和反应中心的恢复速率并不同步,但最终能够恢复到阴生绿叶的水平。

Golden sun leaves of Ligustrum vicaryi could turn green after shadowing treatment.In this paper,the transformation of photosystemⅡ（PSⅡ） in the regreening course was studied by means of two kinds of chl a fluorometer：PAM2100 and PEA.The results indicated that Fv/Fm,F0 and OJIP transients of the golden sun leaves were lower than that of the green shade leaves.Relative intensity of J phase of golden leaves under the double normalization of O-P was higher than that of green leaves.Furthermore,the golden leaves turned green when they were overshadowed,and there were two steps in the recovery course of PSⅡ.Firstly,in the first 2 weeks,F0 increased while Fv/Fm declined;secondly,after 2 weeks,F0 declined while Fv/Fm increased.After two months shadowing,F0,Fv/Fm and OJIP of the golden leaves were similar to that of the shade green leaves.It suggested that most of PSⅡ units of L.vicaryi leaves would be damaged in sunshine condition,and activity of the accepter side was lower than that of donor side in the remainder activated PSⅡ of golden leaves.During shadowing process,the recovery rate of reaction center and the light-harvesting antenna system of PSⅡ of the golden leaves were not synchronous,but both of them could recover to the normal state as that of green shade leaves after 2 month shadowing.