Changes in Pattern of Microtubule Organization During Meiosis in Pollen Mother Cell of Autotetraploid Rice

Changes in microtubule distribution and chromosome behavior in autotetraploid rice during meiosis of pollen mother cell (PMC) were observed in detail using indirect-immunofluorescence laser scanning confocal microscopy. The result showed that microtubule distribution pattern in PMC of the autotetraploid rice was similar to that of the diploid rice during meiosis, but the microtubule behaviors were different, e.g., longer circumferential microtubules and more spindle microtubules in autotetraploid rice. At prophase I, microtubules were decreased in number and distributed unevenly at leptotene. At zygotene, microtubules with unobvious polar distribution formed a diffuse network. At pachytene, nucleolus disintegrated and distorted microtubules structures were found. At diplotene, no circumferential microtubule was found and microtubules depolymerization was observed in advance. At diakinesis, microtubules were decreased in number. Perinuclear microtubules were knitted abnormally. At metaphase I, many abnormalities appeared in spindle. At telophase I, phragmoplast was abnormal, and speckled microtubules were found in the cell. At telophase II-tetra stage, 2 daughter cells did not separate, and microtubules randomly arranged in trifission. These results showed that microtubule abnormal reorganization pattern had a close relationship with abnormal chromosome behavior, which may act synergistically on pollen fertility and seed setting rate of autotetraploid rice.

摘 要应用间接免疫荧光标记-激光扫描共聚焦显微术, 观察了同源四倍体水稻花粉母细胞减数分裂过程的微管骨架和染色体行为变化。结果表明: 同源四倍体水稻花粉母细胞微管组织形态变化与二倍体水稻的基本一致, 但出现一些不同, 如核周微管较长, 纺锤体微管数量较多; 并呈现许多异常现象。前期I细线期, 微管数量少, 分布不均匀; 偶线期, 呈现不规则网络状结构, 未见明显的极性分布; 粗线期, 核仁解体, 呈现混乱的网络状结构; 双线期, 微管提早解聚, 不形成环绕状微管; 终变期, 微管数量稀少, 核周未见明显的微管聚集; 中期I纺锤体形态出现多种异常现象; 末期I成膜体形状异常, 出现点状微管; 末期II-四分体时期, 二分体细胞两端不分开; 出现三分体细胞, 其内微管混乱。以上各时期的染色体行为也出现不同程度的异常。综合认为, 微管组织的异常可能与染色体的行为异常存在一定的关联, 两者共同作用影响花粉发育, 导致育性偏低。