苹果属植物苹果组及山荆子组花粉形态及其演化研究

STUDIES ON THE MORPHOLOGY AND EVOLUTION OF SECT.MALUS LANGENF,AND SECT.BACCATUS JIANG OF GENUS MALUS MILL THROUGH THE POLLEN GRAIN ANALYSIS

苹果属中苹果组和山荆子组的植物花粉为圆球形，近长球形和长球形，花粉Ｐ／Ｅ值在１．０２６０～１．５２７０之间。三购，极轴走向，沟中央较宽，向两极渐细。萌发孔３个，环列于三沟中央，孔沟属Ｎ＿３Ｐ＿４Ｃ５型。花粉中等大小，长轴在２５μ～３０μ左右。外壁为条网纹、条穴纹及条纹饰，无一定规律。但两组条脊间距、宽度和密度有差异。本研究支持ＬａｎｇｅｎｆｅｌｄｓＶ．将原苹果系Ｓｅｒ．ＰｕｍｉｌａｅＲｅｈｄ．与山荆子系Ｓｅｒ，ＢａｃｃａｔａｅＲｅｈｄ．上升为两个组，但在名称上用苹果组Ｓｅｃｔ．ＭａｌｕｓＬａｎｇｅｎｆ．与山荆子组Ｓｅｃｔ．ＢａｃｃａｔｕｓＪｉａｎｇ（不用脱萼组Ｓｅｃｔ．ＧｙｍｎｏｍｅｌｅｓＫｏｅｈｎｅ）。山荆子组花粉的Ｐ／Ｅ值较苹果组大，因此后者较前者进化。

The pollen grains of the species of sect. Malus Langenf.and sect. Baccatus Jiang are spheroidal,subprolate and prolate. The P/E value of these two sections varies from1. 0260 to 1.5270.They are 3 colpi parallel towards the polaraxis. The colpi are wide inthe middle but acuminate at the both ends,3 trema is zonotreme.So the colporate belongsto N_3P_4C_5 type. Pollen grain ranges in the middle sizes and the length of its axis is 25μ to30μ。The exine is sculpture striato-reticulate pattern,striato-faveolate pattern and striatepattern,There are differences among Liraes,Lirae width and Lirae density. The conclusionfrom the research agrees with the view point of Langenfelds V.,which promots Ser.Pumilae Rehd.to sect. Malus Langenf.and Ser. Baccatae Rehd.to sect, Baccatus Jiang(notsect.Gymnomeles koebne,).The P/E value of sect.Baccatus Jinag is larger than that ofsect Malus Langenf.So the former is more primitive than the later,and the later is moreevolutionary than the former.