品质不同的稻米胚乳细胞形态特征的扫描电镜观察

IDENTIFICATION TO QUALITY OF RICE GRAIN WITH SCANNING ELECTRON MICROSCOPE

用扫描电镜观察了品质不同的水稻品种的米粒横断面,看到了一些与米质有关的形态结构特征.根据在电镜下形态完整的胚乳细胞内的淀粉粒是否可见,可将胚乳细胞分为“裸露型”、“非裸露型”和“中间型”三种基本类型.这三种基本类型可作为鉴定米质优劣的主要依据,“非裸露型”胚乳细胞占的比例越大,米质越优,“裸露型”胚乳细胞占的比例越大,米质越劣.淀粉粒的形态结构也是确定米质优劣的一个性状,当淀粉粒呈棱角多面体,大小一致.且粒径较小,紧密结合成复合淀粉粒时是优质米的特征,而淀粉粒为其他形状且结合松散、复合淀粉粒间留有空隙是劣质米的特征.另外,米粒横断面胚乳细胞的排列形式及胚乳细胞的形状与米质也有一定的关系.

To establish the relations between endosperm cell internal structure and ricegrain quality,we examined the kernels of rice varieties by the mid—cross section with SEM andfound that rice grain quality could be readily identified by endosperm cell.The endorperm cellswere divided into“uncovered type”,“covered type”and“Mid—type”according to the starchbeing observable or not in the whole endosperm cell.High proportion of“covered type”wasusually found in varieties of better grain quality and“uncovered type”in varieties with poorergrain quality.In addition,starch shape and size also varied with grain quality.Better grainquality was characterized by starches of rhomb polyhydron shape,uniform size and tightlypacked compound grannules while starch grannules variable in size and shape were often relatedto poorer quality.Finally,arrangement and shape of endosperm cells in cross section of kernelswere also studied.