小花盾叶薯蓣减数分裂与雄配子发育细胞学观察

Cytological study on the Meiosis and Male Gametophyte of Dioscorea parviflora

摘要:

运用压片法对小花盾叶薯蓣(Dioscorea parviflora C. T. Ting)小孢子减数分裂与雄配子体发育进行研究。结果表明: 小花盾叶薯蓣细胞减数分裂中期Ⅱ染色体排列主要有4种类型: 平行型、“八”字型、垂直(同面)、垂直(异面); 四分体有3种类型: 左右对称型、四面体型、交叉型; 小花盾叶薯蓣雄配子发育可分为5个时期: 单核居中期、单核靠边期、单核后期、双核初期和双核期。同时型胞质分裂和2-细胞型花粉证实了小花盾叶薯蓣所在薯蓣科是较原始的被子植物; 小花盾叶薯蓣减数分裂中期Ⅱ染色体排列多样性与2n配子发生无关。

Abstract:

The meiosis and male gametophyte development of Dioscorea parviflora were studied using squash preparation. The results showed that there were four types of chromosome configuration at the metaphase II, such as parallel-type, triangle-type, vertical-type (one plate) and vertical-type (two plate). The microspores in tetrad stage showed three arrangements, such as isobilateral tetrad, decussate tetrad, and tetrahedral tetrad. The male gametophyte development of D. parviflora could be divided into 5 stages, including unicleate central-located stage, unicleate side-located stage, late-unicleate stage, pre-bicleate stage, and bicleate stage. Cytokinesis of microspore mother cells during meiosis was simultaneous type, and pollen grains were 2-cell, it suggested that the Dioscoreaceae was rather primitive in Angiosperm. The diversity of chromosome configurations at the metaphase II had no relationship with the formation of 2n gametes.