杜鹃花属的子叶形态分类

COTYLEDON MORPHOLOGY AND CLASSIFICATION OF GENUS RHODODENDRON

通过对杜鹃花属中4个亚厲104种或变种的广叶形态观察发现:1、杜鹃花属中4个亚属间的子叶形态差异较大,杜鹃花鳞片的有无从子叶上就可以清楚地看出。2、常绿无鳞杜鹃亚属Subgenus Hymenanthes(BL)K.Koch的子叶边缘多只腺体状毛或白、棕色单毛,极少无毛。背面多为暗紫红色或为灰白及灰绿色,叶片多具侧脉少数仅具中脉;有鳞杜鹃亚屈SubgenusRhododendron的子叶边缘无毛或仅少数有白色单毛,背面基部或边缘具可数片,背面多为灰绿色极少暗紫色,叶片多具中脉少有侧脉;映山红亚属Subgeuus Tsutsusi(Sweet)Pojar-kova的子叶边缘无毛或仅一种有毛,背面灰绿色,具侧脉;马银花亚属Subgentis AzaleaslrumPlanch.的子叶近圆形,边缘无毛,具侧脉3-4对,背面白绿色。 有关杜鹃花属子叶形态研究,国外虽有报道,但仅涉及少数种类,最多的也不超过35种,其中野生种仅有7种,其代表性显然是不够的。在国内,有关杜鹃花属于叶形态分类方面的研究目前尚未见报道。杜鹃花是久负盛誉的世界名花,云南是杜鹃花的分布中心之一。观察杜鹃花和子叶形态并进行分类,不仅为杜鹃花的系统发育及杜鹃花属的分类提供佐证而且为杜鹃花的育种提供一个早期的鉴定指标。

Results of observation of the cotyledon morphology of 104 speies and varieties of Rhododendron show that 1. The cotyledon morphology of four subgenera of genus Rhododendron is different, the scales are clearly observed in the cotyledon stage. 2. The cotyledon morphology is as following: In subgenus Hymenanthes. the margin of cotyledon with white, brown glandular hairs or glan-like hairs, rarely?with no hairs, the dorsal face of cotyledon are mostly purpureous, glaucous, or greenish gray, the blades mostly with lateral veins and a few species with median vein only. In subgenus Rhododendron, the margin of cotyledon with no hair or a few species with hairs, the dorsal face of cotyledon is greenish gray and rarely purpureous. There are a few scales on the margin or base of the dorsal face of cotyledon, the blade with median vein and rarely with lateral veins. In subgenus Tsutsutsi, the margin of the cotyledon is with no hair or only one species with hairs, the dorsal face of the cotyledon is greenist gray, the blade is with lateral veins. In subgenus Azaleastrum, the cotyledon is nearly round, without hairs on the margin and with three to four pairs of lateral veins.It was reported about the research on cotyledon of genus Rhododendron abroad, but merely involved 35 species and seven Chinese wild Rhododendron species. The present author has not seen the report.Rhododendron is famous all over the world. Yunnan is one of the centers of distribution of Rhododendron. This paper is not only offered the evidence for evolution and classification of genus Rhododendron, but also offered an appraise target for breeding of Rhododendron.