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.