栽培稻机动细胞硅酸体的形态特征及其在籼、粳亚种间的差异

Morphological Characteristics of Silica Bodies from Motor Cells in Rice ( Oryza sativa L.) and Their Differences Between indica and japonica

来源于水稻（ＯｒｙｚａｓａｔｉｖａＬ．）叶片机动细胞硅酸体的植物蛋白石，作为古代稻作的直接证据和籼、粳分类的指标，在稻作起源和传播以及籼、粳亚种演化的研究中具有重要意义。以中国水稻地方品种和改良品种为材料，分析了水稻机动细胞硅酸体的长、宽、厚和形状系数ｂ／ａ这４个形态性状在品种内、品种间和籼、粳亚种间的变异情况。结果显示，不论是籼稻还是粳稻，同一品种不同硅酸体的形态均有明显差异，表明单个或少数几个机动细胞硅酸体不足以代表该品种硅酸体的形态特征。以５０个硅酸体的平均值为代表进行比较的结果表明，机动细胞硅酸体上述４个形态性状在同一品种不同单株或同一单株的剑叶与倒三叶之间没有明显差异；而在同一叶片的叶基、叶尖和中间３个部位之间却有明显差异；在同一亚种的不同品种之间差异也达极显著水平；籼粳亚种间变异是硅酸体形态变异的主要方向。籼、粳两个亚种硅酸体形态性状的频率分布虽然存在很大程度的重叠，但籼稻的硅酸体形状较小、较薄，ｂ／ａ较大；相反，粳稻的硅酸体形状则明显存在较大、较厚、ｂ／ａ较小的趋势。因此，根据机动细胞硅酸体的４个形态性状可以判别籼、粳稻，其判别效率可达８５％以上。

Plant opal, derived from silica body of motor cell in leaf blade of rice( Oryza sativa L.) and can be excavated from archaeological sites, has been used for studying the origin and spread of rice cultivation and the differentiation of indica and japonica . Variations of the morphological characters of vertical length(VL), horizontal length(HL), lateral length(LL) and shape coefficient (b/a) of the silica bodies of 52 native varieties and 65 improved varieties in China within variety, between varieties and between indica and japonica were investigated. The results showed that there was a great significant difference within the same variety for the four morphological characters of silica bodies, whether indica or japonica rice, indicating that the morphological features of silica bodies of a variety can not be described by one or a few silica bodies. When compared by the averages of 50 silica bodies, no difference was observed among plants or leaf positions in the same variety.However, there was a great significant difference among the different parts of the same leaf blade.Significant difference was also found among different varieties whether in indica or japonica rice.The difference between indica and japonica was much greater than that among varieties of indica and japonica rice.There was an obvious tendency for the indica variety to have smaller morphological dimensions and greater b/a,and for the japonica variety to have larger morphological dimensions and smaller b/a. It is possible to discriminate rice groups of indica and japonica based on the shape of silica body and the efficiency of discrimination could be over 85%.