不同叶色矢竹叶绿体结构和光系统特性差异

以矢竹(Pseudosasa japonica)、花叶矢竹(P.japonica f.akebonosuji)和曙筋矢竹(P.japonica f.akebono)为研究对象,借助叶绿体超微结构和荧光动力学曲线的变化揭示不同叶色矢竹的光系统活性及光合特性差异。结果表明:3个竹种的光合色素含量差异明显,除花叶矢竹条纹叶白色部分叶绿体内无完整类囊体片层结构外,花叶矢竹绿条纹和曙筋矢竹的基粒数明显少于矢竹,叶绿体发育成熟度不一致;OJIP曲线及参数表明,花叶矢竹条纹绿叶和曙筋矢竹光系统II(PSII)反应中心开放降低程度低于矢竹,捕获能量用于电子传递的份额变小,PSII活性变弱;而曙筋矢竹叶片P700至初级电子受体(QA)的电子传递链氧化还原平衡偏向于还原侧,推测其光系统I(PSI)反应中心P700至PSII QA电子传递链受损。因此,PSII活性变化导致叶绿体发育不成熟,可能是引起矢竹类叶色差异的直接原因。

Chloroplast Ultrastructure and Chlorophyll Fluorescence Characteristics of Three Cultivars of Pseudosasa japonica

We explored the different photosynthetic characteristics of three Pseudosasa cultivars: P. japonica, P. japonica f. akebonosuji, and P. japonica f. akebono. The differences in photosystem activity and photosynthetic characteristics of different leaf colors were revealed by the changes of chloroplast ultrastructure and fluorescence kinetics curves. The results showed that the photosynthetic pigment content of the three species was significantly different. Except for the intact thylakoid layer structure in the white part of the chloroplast, the green streak and the radix were significantly less than the radix. The chloroplast developmental maturity is inconsistent; the OJIP curve and parameters indicate that the open reduction of the flowering green leaf and the saplings of the PSII reaction center is lower than that of the yam, the capture energy that is used for the electron transfer share to be smaller, and the PSII activity is weaker; The redox balance of the electron transport chain of bamboo leaves P700 to Q_A is biased towards the reducing side, and it is presumed that the P700 reaction center P700 to PSII primary electron acceptor Q_A electron transport chain is damaged. Therefore, the chloroplast development caused by changes in PSII activity in the photosystem is immature, which may be the direct cause of the difference in leaf color of the species.