Cytological Study On Anther Development Of Japonica Low Thermo-sensitive Genic Male Sterile Rice Under Different Temperature Conditions

Japonica low Thermo-sensitive Genic Male Sterile Rice is fertile in high temperature and sterile in low temperature. The study selected Japonica Low Temperature Sensitive Male Sterile Rice304for research materials, put the materials in the natural high temperature and low temperature22℃.Through anther compressor method, semi-thin section method, ultramicrotomy, PAS reaction and the staining of ultrastructure to observe the process of anther development, the distribution of starch grains in the anther and the ultrastructure of anther to find the period of pollen sterility and the reason of anther abortion. The aim of the study is to provide the basis for theoretical research of rice male sterility mechanism.The main results are as follows:1. Japonica Low Temperature Sensitive Male Sterile Rice304is fertile in natural high temperature condition and sterile in low temperature22℃.2. Comparing the microstructure of fertile and sterile anther development of japonica low thermo-sensitive genic male sterile rice304under different temperature conditions. In fertile anthers, there are rich inclusions in mother cells and the mother cells can success through meiosis. In dyad and tetrad stage, the tapetum arranged rules.In early microspore stage,tapetum cells appear degenerate phenomenon.With the anther development,the large vacuole pushed the nucleus of microspore to opposite side of the pollen hole, the tapetum cells are further shrinked, only leaving tapetum cell remnants in the late microspore stage. There are rich inclusions in the mature pollen, pollen rounded.In sterile anthers,many mother cells can through meiosis. There are vacuoles in tapetum cells and the shape of tapetum cells are irregular in the dyad and tetrad stage.The tapetum cells are serious degeneration and the shape of microspores are irregular in microspore stage.There are no inclusions in mature pollen,only leaving pollen wall.3. Starch grains gradually reduced during the development of the fertile and sterile anthers. The distribution of starch grains is different in the same period in the development of fertile and sterile anther.The distribution of starch granules in fertile anther more than sterile anther and big in anther mother cell stage.From the period of the dyad to the late microspore stage of anther development,the starch grains within the parenchyma cells and endothecium cells in sterile anthers less than fertile anthers in the same period.There are no starch grains in mature pollen of sterile anthers.4. Comparing the ultrastrueture of fertile and sterile anther development of japonica low thermo-sensitive genie male sterile rice304.In fertile anther mother cell stage, the anther mother cells have strong cytoplasmic, regular shape and rich in mitochondria and endoplasmic reticulum, in this period,there are a large number of black granular sporopollenin distribute in plasmid of tapetum cells;In meiosis period,the tapetum cells have strong cytoplasm and rich in plasmid, in this period,sporopollenin on the surface of the plasmid;In early microspore stage of fertile anther, cytoplasm of tapetum cells contracted,show obvious degenerate signs, sporopollenin distribute on the surface of ubisch bodies. In sterile anthers, the anther mother cells have thinc ytoplasmic and less mitochondria,plastids and endoplasmic reticulum.In meiosisperiod,tapetum cells have severe vacuolization,dyad split unnormal and irregular in shape.Some microspores of sterile anthers can develop to the microspore stage,the tapetum cells are still complete and sporopollenin distribute in plasmid in this period. Through the research on fertile and sterile anther of japonica low temperature sensitive male sterile rice304can determine sterile anthers began to appear abnormalities in the microspore mother cell stage,abortion occur in both meiosis and early microspore;pollen sterility in sterile anthers is caused by the early degradation of tapetum cells.