香稻胚乳的垩白性状研究及扫描电镜观察

【目的】研究不同香稻品种垩白性状与胚乳细胞和淀粉粒的形状结构、排列方式及发育情况的关系,为进一步研究香稻垩白性状的形成机理及培育优良品质的香稻新品种打下基础。【方法】通过田间试验,调查11个香稻品种的垩白粒率、垩白面积和垩白度,并对香稻品种胚乳细胞及淀粉粒进行电镜观察。【结果】供试11个香稻品种间差异最明显的垩白性状为垩白粒率,其次是垩白面积,最小的是垩白度,垩白粒率和垩白度成正比,垩白粒率越高则垩白度越高。不同香稻品种稻米胚乳细胞的排列方式、形态及其横断面淀粉粒的分布存在明显差异,其与垩白性状的形成存在一定关联,根据稻米胚乳中垩白形成的位置不同,可将垩白性状分为腹白、心白和背白3种垩白亚类。同一香稻品种,垩白米与无垩白米在淀粉粒形状结构及排列方式等方面也存在明显差异,但垩白米的透明部位和无垩白米的淀粉粒间无明显差异,且垩白度低的部位淀粉粒发育良好。【结论】香稻稻米的垩白性状与胚乳细胞和淀粉粒的形状结构、排列方式及发育情况密切相关,可用于香稻稻米品质鉴定。

Chalkiness characters and scanning electron microscope observation of fragrant rice endosperm

Objective]In order to lay foundation for researching mechanism of grain chalkiness formation and breeding new high-quality fragrant rice varieties,the present study was conducted to investigate relation of chalkiness formation with structure,development and arrangement of endosperm and starch granule for different fragrant rice varieties. Method]Field trial was conducted to investigate chalkiness characters such as degree of percentage of grains with chalkiness (PGWC), endosperm chalkiness(DEC) and square of chalky endosperm(SCE) in eleven fragrant rice varieties. In addition,the en-dosperm structures and starch granules of rice grains were also observed by scanning electron microscope (SEM). Result]Results showed that,among eleven fragrant rice varieties,the biggest difference was PGWC,followed by SCE,and the last was DEC. There was proportional relationship between PGWC and DEC. Moreover ,there were some differences in arrange-ment of endosperm cells,distribution of starch granules and among different fragrant rice varieties,which was certainly cor-related with occurrence of chalkiness characters. According to chalkiness location on or within the endosperm ,grain chalk-iness could be divided into sub-types namely white belly,white core and white back among fragrant rice varieties. As for the same fragrant rice variety,there were obvious differences in starch granules of grains between chalky and non-chalky, while there were not obvious differences in starch granules between transparent parts of chalkiness grains and non-chalky grains,and the starch granules developed well in the location with low DEC. Conclusion]The chalkiness formation is closely related to structures, arrangement and development of endosperm and starch granules of different fragrant rice varieties. The results will provide useful references to identify quality of fragrant rice varieties.