月季营养苗端的组织学和细胞学研究

HISTOLOGICAL AND CYTOLOGICAL STUDIES ON SHOOT APEX IN ROSA CHINENSIS

The vegetative shoot apex in Rosa chinensis Jacq. has two layers of tunica cells. The promeristem in the shoot apex consists of tunica, corpus and leaf primordium. Observing tunica and corpus in the promeristem center under an electron microscope, there were seen many rough endoplasmic reticulums, mitochondria and plastids which even more in tunica and corpus within the leaf buttress. The primary meristem, in which the vacuolization of cell begins and the mitosis being still frequent, is derived from the promeristem. It consists of the protoderm, fundamental meristem, mesophyll meristem and protocambium. All the primary meristems, except the centric fundamental meristem, contain a large amount of rough endoplasmic reticulum and other cell organs. The ratio of the cytoplasm is low due to the high vacuolization of the cell in the centric fundamental meristem. Therefore, the tunica and corpus of the leaf buttress and all the primary meristems with higher mitosis frequency form the vigorous zone while those of the centric promeristem and fundamental meristem with lower mitosis form the quiescent zone in the shoot apex.