叶籽银杏胚乳淀粉特性及系统学意义

 旋光法和凯氏定氮法测定表明，叶籽银杏正常种子和叶生种子胚乳淀粉含量分别为63.22%和61.91%；蛋白质含量分别为11.35%和13.36%。SEM 观察结果表明，叶籽银杏淀粉粒形状大多为球形和椭圆形，有A、B、C（大、中、小）3 种类型。正常种子和叶生种子均含有A 和B 型淀粉粒，C 型淀粉粒仅在叶生种子中发现。正常种子A 型淀粉粒大小为14.28 μm × 11.96 μm，长轴/短轴比为1.24；叶生种子分别为13.63 μm × 10.55 μm 和1.30。正常种子B 型淀粉粒大小为8.29 μm × 7.28 μm；叶生种子为8.90μm × 7.68 μm。叶生种子C 型淀粉粒大小为2.07 μm × 1.84 μm。与正常种子相比，叶生种子淀粉粒特点是大小不一，B 型和C 型淀粉粒明显可见以“出芽”方式从大淀粉粒上长出，淀粉粒间空隙大，基质蛋白丰富，淀粉粒上有凹陷区。淀粉粒类型、大小、形态和含量在不同单株间存在较大差异，不同单株的基质蛋白质存在较大差异,尤其在正常种子和叶生种子间淀粉粒和蛋白质相互连接方式及在淀粉粒上的分布差异明显。叶生种子淀粉含量低及形态多样性与其胚乳发育滞后、种粒小有关。对叶籽银杏淀粉粒的系统学意义进行了探讨。

Comparison on Starch Characters in Endosperm of Ginkgo biloba var. epiphylla Mak.and Its Systematic Significance

The endosperm of normal seed and epiphyllous seeds were determined by Polarimetry and Kjeldahl nitrogen method.The result showed that the starch contents were 63.22% and 61.91%,and the protein contents were 11.35% and 13.36%,respectively.Observation by scanning electron microscopy(SEM)showed that most starch grain were spherical and elliptical,which can be divided into three types:A(large grain),B(medium grain),C(small grain).Type A and type B were contained in both normal seed and epiphyllous seeds,while t...