关键词: 叶籽银杏, 叶生种子, 淀粉粒, 胚乳淀粉含量, SEM 观测, 系统学评价

Abstract: 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 type C was only observed in epiphyllous seeds. The size and the ratio of long axis to short axis of A starch grain in nomal seeds were 14.28 μm × 11.96 μm and 1.24，which in epiphyllous seeds were 13.63 μm × 10.55 μm and 1.30，respectively. The size of B starch grain in normal seed and epiphyllous seeds were 8.29 μm × 7.28 μm and 8.90 μm × 7.68 μm，respectively. The size of C starch grain was 2.07 μm × 1.84 μm. Compared with normal seed，the starch grain in epiphyllous seeds has following properties: different in size, type B and type C starch grain were obvious, the starch grains producted by “gemmation” from large grain, interspaces among starch grain were large, stromatin were abundant, and there were concave field in starch grain. There were significant differnces in starch grain
types, size, shape and content as well as the stromatin among different individual, especially in the connection mode of starch grain and proteins in normal seeds and epiphyllous seeds and in the stromatin distribution on the starch grain. The low content of starch and various shape of epiphyllous seeds was related to delay development in endosperm and small seed size. The systematic significance of the starch grain in Ginkgo biloba var. epiphylla Mak. was discussed in this paper.

Key words: Ginkgo biloba var. epiphylla Mak., epiphyllous seeds, starch grain, starch content in endosperm, SEM observation, systematics evaluation