杂交水稻主要亲本材料的垩白性状及其胚乳结构电镜扫描

Study on Chalkiness Characters and Endosperm Structures of the Main Parents' Kernel of Hybrid Rice

【研究目的】针对杂交稻米品质问题,研究杂交稻亲本垩白形成与胚乳细胞形态结构和发育以及与淀粉粒之间的关系,为进一步研究杂交稻米高垩白形成机理奠定基础;【方法】对几个应用面积较大的杂交稻主要亲本和两个米质对照品种,按GB/T17891-1999方法调查其垩白性状,对其米粒胚乳结构和淀粉粒的采用扫描电镜观察分析;【结果】亲本材料间垩白性状差异首先表现在垩白率上,其次为垩白度,最后为垩白面积。高垩白的保持系和桂朝2号垩白主要发生在中、腹部,而相对低垩白的恢复系主要在中部,腹白少或无。垩白度与垩白率间存在明显的线性关系,与垩白面积无明显相关性。淀粉粒在米粒横断面上分布的均匀性与垩白率和垩白度有较大的相关性,分布越均匀则垩白率和垩白度越小;而长方柱状细胞层数和多少与垩白率和垩白度有一定的相关性但不明显。5个恢复系和3个保持系垩白米粒的背部淀粉粒普遍发育良好而中部较差;保持系与恢复系的差异主要表现在腹部淀粉粒的发育形态上。【结论】杂交稻保持系与恢复系的垩白发生部位有所差异,垩白形成与其淀粉粒的分布有重要关系;中、腹部淀粉粒发育异常容易产生垩白,主要受胚乳细胞生理发育规律的影响。

[OBJECTIVE] In allusion to the quality of hybrid rice kernel, we would like to study the relation of the chalkiness formation and the development of endosperm structure and starch granule of hybrid rice parents, so as to be convenient for the clarification of high chalkiness of hybrid rice. [METHOD] The chalkiness characters were investigated as GB/T17891-1999. The endosperm structure and starch granules were observed with scanning electron microscope （SEM）. [RESULTS] The results showed that the remarkable difference of chalkiness characters between maintainers and restorers of hybrid rice was grains with chalkiness （PGWC） and degree of endosperm chalkiness （DEC）, while square of chalky endosperm （SCE） had no distinctive difference between maintainers and restorers. Chalkiness of maintainer was easily produced in the middle and abdomen of kernel, while that of restorer was only produced in the middle. The distribution uniformity of starch granule in the kernel transect correlated with chalkiness. The starch granule was more uniform, the chalkiness in kernel was much less. But the cuboid cells in endosperm were not the key parameter affecting chalkiness formation. Almost all of the maintainers and restorers could develop the starch granule in kernel backside all right and badness in middle kernel. The main difference of starch granule between maintainers and restorers was in abdomen of kernel, where starch granule .developed well in restorers but badly in maintainers. [CONCLUSION] The chalkiness positions are different between maintainers and restorers of hybrid rice parents. It has an important relation with the starch distribution in endosperm. The heteroplasia of starch granules in center and abdomen of endosperm easily leads to come into being chalkiness. The development of starch granules is closely relevant to the transport way of filling materials.