甘蔗叶不同部位ATP酶活性细胞化学定位

甘蔗叶片,叶鞘和肥厚带韧皮部 ATP 酶活性定位于筛管、伴胞的质膜、内质网和某些伴胞细胞基质、小囊泡和发育成熟的液泡上;叶片韧皮部薄壁细胞、厚壁细胞和厚壁通道细胞质膜及小囊泡中亦显示有 ATP 水解产物;维管束鞘细咆与厚壁细胞或厚壁通道细胞所构成的细胞间隙上也存在有 ATP 酶活性反应产物沉淀。甘蔗叶片大、中、小三种维管束,从小维管束到大维管束,面向细胞间隙的细胞表面上的 ATP 酶活性逐渐增强,而维管束鞘细胞质膜上的 ATP 酶活性则趋于减弱;同一维管束内则以韧皮部细胞的 ATP 酶活性最强。维管束鞘细胞与叶肉细胞之间存在很多的胞间连丝,并表现出高的 ATP 酶活性。讨论了 ATP 酶活性的分布状态与叶肉细胞的光合产物向韧皮部运输的关系。

CYTOCHEMICAL LOCALIZATION OF ATPase ACTIVITY IN THE CELLS OF VASCULAR BUNDLE OF DIFFERENT PARTS IN SUGARCANE LEAVES

The results obtained by the cytochemical localization of ATPase activity reaction indicate that the high enzyme activity was exhibited at the plasmalemma and endoplasmic reticulum in sieve elements and companion cells,and observed in the ground cytoplasm,vesicles and va- cuoles of some companion cells.The reaction products of ATPase activity were also found at the plasmalemma and in the vesicles of parenchymatous,sclerenchymatous and mestom cells,and shown in intercellular spaces between the bundle sheath cells and the sclerenchyma cells or the mestom cells.The reaction strength of ATPase activity in different kinds of vascular bundles and its neighbouring mesophyll cells appeared to be not consistent.The activity at the free surfaces of mesophyll cells around large vein is higher than that of middle vein,and that of small vein is the lowest.Contrarily,the ATPase activity at the plasmalemma in small vein sheath cells is higher than that of middle and large vien.The highest ATPase activity was localized at the plasmalemma of phloem cells.Very high ATPase activity was also found at the plasmodesmata between the bundle sheath cell and the mesophyll cell.The results suggest that the photosynthates may be moved from mesophyll cells into bundle sheath cells through the plasmodesmata,and exported to apoplast of phloem from chlorenchymatous bundle sheath cells,and then actively loaded into the sieve element-companion cell complex.