Romanowska Elzbieta, Drozak Anna
Department of Plant Physiology, Warsaw University, Warszawa, Poland.
Acta Biochim Pol. 2006;53(4):709-19. Epub 2006 Nov 14.
The photochemical characteristics of mesophyll and bundle sheath chloroplasts isolated from the leaves of C4 species were investigated in Zea mays (NADP-ME type), Panicum miliaceum (NAD-ME type) and Panicum maximum (PEP-CK type) plants. The aim of this work was to gain information about selected photochemical properties of mesophyll and bundle sheath chloroplasts isolated from C4 plants grown in the same moderate light conditions. Enzymatic as well as mechanical methods were applied for the isolation of bundle sheath chloroplasts. In the case of Z. mays and P. maximum the enzymatic isolation resulted in the loss of some thylakoid polypeptides. It was found that the PSI and PSII activities of mesophyll and bundle sheath chloroplasts of all species studied differed significantly and the differences correlated with the composition of pigment-protein complexes, photophosphorylation efficiency and fluorescence emission characteristic of these chloroplasts. This is the first report showing differences in the photochemical activities between mesophyll chloroplasts of C4 subtypes. Our results also demonstrate that mesophyll and bundle sheath chloroplasts of C4 plants grown in identical light conditions differ significantly with respect to the activity of main thylakoid complexes, suggesting a role of factor(s) other than light in the development of photochemical activity in C4 subtypes.
对从玉米（NADP-苹果酸酶型）、黍（NAD-苹果酸酶型）和大黍（PEP-羧激酶型）植物叶片中分离出的叶肉和维管束鞘叶绿体的光化学特性进行了研究。这项工作的目的是获取有关从生长在相同适度光照条件下的C4植物中分离出的叶肉和维管束鞘叶绿体的选定光化学特性的信息。采用酶法和机械法分离维管束鞘叶绿体。对于玉米和大黍，酶法分离导致一些类囊体多肽的损失。研究发现，所有研究物种的叶肉和维管束鞘叶绿体的PSI和PSII活性存在显著差异，这些差异与色素-蛋白复合体的组成、光磷酸化效率以及这些叶绿体的荧光发射特性相关。这是第一份显示C4亚型叶肉叶绿体光化学活性差异的报告。我们的结果还表明，在相同光照条件下生长的C4植物的叶肉和维管束鞘叶绿体在主要类囊体复合体的活性方面存在显著差异，这表明除光照外的其他因素在C4亚型光化学活性的发展中起作用。
