三倍体葡萄‘夏黑’的花粉母细胞减数分裂行为观察及其育性研究

为探究三倍体葡萄‘夏黑’的育性及其细胞学机制,对其花粉母细胞减数分裂进程中的染色体行为及育性水平进行研究。结果表明:(1)三倍体葡萄‘夏黑’花粉母细胞减数分裂进程中存在部分染色体提前分向两极、落后染色体、染色体桥、平行纺锤体、不均等分离、微核等染色体异常行为,其中不均等分离现象出现的频率最高(65.68%)。(2)‘夏黑’葡萄的花粉离体萌发率为1.65%,花粉直径大小范围在18.0~50.0μm之间,且花粉直径分布呈双峰型。(3)‘夏黑’葡萄具有一定的育性,作为亲本与四倍体品种杂交均获得了杂交子代。研究认为,减数分裂的异常是三倍体葡萄‘夏黑’育性低的细胞学原因,但同时也形成了少量可育的未减数配子,可以作为中介材料应用于葡萄育种。     

Membranes in the spindle of Iris pollen mother cells during the second division of meiosis

Summary Spindle membrane in the second division of meiosis inIris comprises endoplasmic reticulum (ER) and small spherical vesicles (40–80 nm diameter). The vesicles are in all respects similar to those of dictyosomes and it is proposed that they originate in the Golgi system. ER on the other hand is generated from the nuclear envelope (NE). Invaginations and evaginations of the inner and outer membranes of the NE are present at interphase and they enlarge during prophase II and break to form spindle ER elements at the beginning of prometaphase II. The area enclosed by this ER continues to increase until the entire spindle is filled with irregular profiles at mid-prometaphase II. During late-prometaphase II the quantity of ER decreases and, concurrent with an increase in the number of microtubules (MTs), the cisternae align alongside MT bundles and accumulate at the poles. It is suggested that ER increases in quantity by growth of NE membranes. Furthermore, the alignment of ER along the interpolar axis and its transport polewardsprior to anaphase suggest the action of a force on each ER element.