Karyological observations on the occurrence of meiosis in the life cycle of Porphyra haitanensis Chang ef Zheng (Bangiales, Rhodophyta)

摘要

The occurrence of meiosis in the life cycle of the heteromorphic dioecious marine red alga, Porphyra haitanensis, is described. Chromosome numbers indicated that conchosporangial cells and conchospores are diploid (2n=10), while two- and three-celledstages of conchospore germlings, vegetative cells and spermatia of the gametophytic blades are haploid (n=5). We observed karyological changes in leptotene, zygotene, pachytene, diakinesis, metaphase and anaphase of the meiosis, and the change in ploidyat the two-celled stage of conchospore germling. Characteristics of the first division of the conchospore and the change in ploidy at the two-celled stage indicated that meiosis I occurs during the germination division of conchospore in this species.