杜鹃属马银花亚属花粉形态的研究

Pollen Morphology of Rhododendron Subgenus Azaleastrum

首次报道了杜鹃属马银花亚属四组 2 0种 2变种植物的花粉形态。本亚属植物的花粉均为四合花粉 ,呈正四面体排列 ,四合体直径为 35 .85～ 6 0 .72 μm。单粒花粉球形或近球形 ,具三孔沟。在四合花粉上 ,相邻花粉粒上的沟相连 ,花粉粒表面或多或少具粘丝。在扫描电镜下 ,花粉粒呈现出粗糙、不明显聚颗粒状至致密的聚颗粒状等不同的纹饰 ,在不同的组间存在或多或少的差异 ,具有一定的分类学意义。对某些种的分类处理也能够提供某些孢粉学证据。

Pollen grains of 20 species and 2 varieties in 4 sections of genus Rhododendron subgenus Azaleastrum were examined by light microscope (LM) and scanning electron microscope (SEM) for the first time.The pollen grains of subg.Azaleastrum are arranged in tetrahedral tetrad,the tetrad diameter ranges from 35 85 μm to 60 72 μm.A single pollen is spheroidal or subspheroidal,with tricolporate aperture,which shaped as half colpus due to two neighborly grains of tetrahedral tetrad link together,and viscin threads can be seen on the pollen surface.The exine sculptures of subg.Azaleastrum can be divided into scabrid,compact granulate and unconspicuous granulate types in SEM.The exine sculptures are different among different sections in subg.Azaleastrum and therefore can provide some proof for identification of some species in Rhododendron.