金沙江中游地区山茶组4居群植物形态及花粉特征观察及其分类讨论

Observation on the plant and pollen morphological characteristics of four sect.Camellia populations and discussion on its classification from the middle reach of Jinsha River

关键词:  金沙江  山茶组  花粉  形态特征  西南山茶

Key words:  Jinsha River  sect.Camellia  pollen  morphological characteristics  C.pitardii

摘要:

对金沙江中游地区4个山茶组居群进行长期形态特征观察，并对其中32株的花粉进行了光学显微镜和电镜扫描观察。结果表明：不同居群及同一居群内不同植株间具有某些共同的形态特征，但具有明显的多样性、连续的变异性和性状的交叉性；花粉粒多为大型，形状为长球形，偶有超长球形、近长球形和不规则形状，极面观为三裂圆形、三裂近圆形和三裂钝三角形；花粉粒的外壁纹饰具有较明显差异，具皱疣状、皱网状、皱穴状、脑纹状、条状和网穴状等多种纹饰类型，但属于种内多型现象。研究结果认为该地区山茶虽在某些表征上差异明显，但幼枝和叶背无毛，叶片先端长渐尖或尾尖，花丝无毛，花柱合生，花、果及叶均较大等共同特征，均应属于山茶组的西南山茶。

Abstract:

The morphology of four populations of sect.Camellia from the middle reach of the Jinsha River was observed over an extended period，and pollens of 32 plants were examined under optical microscope and SEM. The results indicated that different plants had some common morphological characteristics，but with significant diversity，continuous variability and cross character traits. The pollen grains were generally large，usually prolate in shape，occasionally perprolate，subprolate or irregular，and 3 lobed circular，3 lobed subcircular or obtuse triangular in polar view. The pollen exine ornamentation had the following six types:regulate verrucate，regulate reticulate，regulate foveolate，cerebroid，striate and reticulate foveolate patterns，but the pollens belonged to the various types in one species. From the studies，we could conclude that the differences were significant in some characteristics of plants of sect.Camellia from the middle reach of Jinsha River，however，the plants had the following common characteristics:young branches and leaves glabrous，leaves apex long acuminate to caudate，filaments glabrous，style connate，flowers，fruit and leaves bigger，so these plants should be part of C.pitardii.