阔口尖毛虫无性生殖和生理改组过程的比较

THE COMPARISON BETWEEN ASEXUAL REPRODUCTION AND PHYSIOLOGICAL REORGANIZATIONOF Oxytricha platystoma

阔口尖毛虫无性生殖中先后发生后口围带原基,前、后的波动膜原基,额腹横棘毛原基和左、右缘棘毛原基,老口围带也在此期间更新,结果形成2套新纤毛结构,原老结构瓦解消失;生理改组时按同样顺序产生口围带原基等几类腹面纤毛原基,结果形成1套新纤毛结构,替换老结构。在这两个截然不同的过程中,新纤毛结构的分化和老纤毛结构退化时也表现出某些相似的特征。作者据此推测,这种纤毛虫无性生殖和生理改组中,纤毛原基的发生、发育和定位在细胞控制机理上可能是相同的。

Protargol staining technique and scanning electron microscopy are used to study the morphology of Oxytricha platytoma, and morphogenesis of the ventral ciliatures during asexual reproduction and physiological reorganization. During asexual reproduction, adoral zone of membranelles primordium(AZMP, future opisthe) occurs at first, then, undulating membrane primordium(UMP), trontal-ventral-transverse cirri primordia(FVTP)and left- & right marginal cirri primordia (LMP, RMP) (future proter and opisthe) appear in succession while old AZM renews. The result is that two sets of ventral ciliatures are developed and old cilialures are disintegrated and disappeared. During physiological reorganization, AZMP, UMP, FYTP, LMP, and RMP formed in the same sequence as asexual reproduction. As a results, a set of ciliatures are produced and old ciliatures are replaced by the new ones. Because there are certain similar characters in the differentiation of new ciliatures and the degeneration of old ones, it is postulated that the regulation mechanism is same in occuring, developing and locating of the ciliary primordia ior both the asexual reproduction and the physiological reorganization.