稀莶属三种植物的核形态学研究

研究了稀莶属３种植物的染色体核形态结构，除稀莶的染色体数目曾有报道外，毛梗稀莶、腺梗稀莶还未有报道，３种植物的核型为首次报道。它们的静止核均属于复杂染色中心微粒型，分裂前期染色体均属于渐变型。中期体细胞染色体数目都为２ｎ＝３０，本属的染色体基数为ｘ＝１５，核型分别为：（１）腺梗稀莶２ｎ＝３０＝２９ｍ＋１ｓｍ，属于１Ｂ型；（２）毛梗稀莶２ｎ＝３０＝２８ｍ＋２ｓｍ，属于１Ｂ型；（３）稀莶２ｎ＝３０＝２

A KARYOMOPHOLOGICAL STUDY OF THREE SPECIES OF GENUS SIEGESBECKIA

Karyomophological studies on the three species of genus Siegesbeckia from Kunming of China were carried out by root tips squash method. The three spedes were found to have the same chromosome numbers 2n = 30, basic chromosome number in this genus was x = 15, belonged to diploid. The morphology of the resting nuclei and that of the mitotic prophase chromosomes are very similar among the three species and can be classified as complex chromocenter and gradual types respectively. At mitotic metaphase, their karyotype formulas and karyotype asymmetry were showed as follows:(1) Siegesbeckia pubescens Makino. 2n = 30 = 29m 1sm, belonged to 1 B type;(2) Siegesbeckia glabrescens Makino. 2n = 30 = 28m 2sm, 1 B type;(3) Siegesbeckia orientalis L. 2n = 30 = 26m 4sm, 2A type;The karyotypes of three spotes were investigated for the first time except chromosome numbers of S. orientalis was reported.