| Photoperiod-sensitive male sterile rice Nongken 58S occur fertility transition under different sunshine. The pollen is completely sterile under long-day high-temperature conditions while short-day low temperature can be sterility, so that we could use it as two-line hybrid rice. Based on 58S have this characteristics which regulated male fertility by external factors, it is very important in rice breeding programs and as well as a good material for study the mechanism of plant male sterile. In this paper, we used the PEG sections-indirect immunofluorescence labeling technique to compare the microtubule configuration changes of photoperiod sensitive genic male sterile rice (PGMR) Nongken58S and normal fertile Nongken58N during microsporogenesis. At the same time, we discuss the relationship between 58S microsporogenesis and the changes of microtubule in this process. It provided cytological evidence of infertility for comprehensive understanding of photosensitive genic male sterility mechanism and cloning sterility gene.Pollen germination and pollen tube growth of plants is an important step in pollination and fertilization, affecting plant seed. Many reports have already indicated that the microfilaments are closely related with pollen germination, pollen tube growth and protoplast flow of pollen tube. In this study, microfilament pattern during pollen germinationand and pollen tube were observed with a simple method in which there was no pre-fixation,with dimethylsulphoxide(DMSO) as a permeabilising agent and staining with FITC-Phalloidin. These results provided basic data in order to further study the relationship between the microfilament cytoskeleton and pollen tube growth.The main results were following:1. Changes in the pattern of organization of microtubules during microsporogenesis of Nongken58NMeiotic-prophase I, formed pernuclear microtubule in PMC; meiotic-metaphase I, microtubules reformed into spindle microtubules; meiotic-anaphase I, spindle fibers microtubule arised in the center part of PMC; meiotic-telophase I, formed phragmoplast microtubule; in each dyad cell,there were radial microtubule around the nucleolu; tetrad stage, pernuclear microtubule appeared in each tetrad cell; early microspore stage, microtubules randomly distributed in the cytoplasm of a reticulated..2. Changes in the pattern of organization of microtubules during microsporogenesis of sterile Nongken58SMost Nongken58S have same changes in the pattern of organization of microtubules during microsporogenesis as Nongken58N. But some Nongken58S microspore mother cell cytoplasm does not exist within the reticular perinuclear microtubules and were less than normal, they only exists in the nuclear layer around the microtubule. These small changes in microspore mother cells of microtubules may lead to some microspore abortion. In addition, part of the Nongken58S metaphase spindle formed were very abnormal, some showed broad poles, some distorted or longer than normal and some were quite incompletely formed spindles. These abnormal spindles may lead to parts of microspores of Nongken58S abortion as for the abnormal meiosis.3. Characteristics of rice pollen germination in vitro and the distribution of microfilament in pollen tubesThe pollen germinated after hydration for 2min and the growth speed of pollen tube was between 600-1500μm/h. In the hydration of the pollen grains without germination, a number of short fusiform microfilaments constituted a network-like structure. In the germination process, some microfilaments gradually transferred to the pollen tube as the short fusiform microfilaments releasing and their distribution mainly along the pollen tube were longitudinally. As the pollen tube elongation, microfilaments were mainly in the middle and front region of pollen tube, but there were no obvious microfilaments in the tip of pollen tube.The distribution of microfilament was diffuse and irregular in certain non-germination pollen. Some pollen germinated for the same time but shorter, the microfilaments were less and mainly gathered in the region near the apertures. This indicated that the distribution of microfilament cytoskeleton affected the germination and growth.of rice pollen tube. |
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