都支杜鹃茎、叶解剖特征与环境的适应性

利用光学显微解剖技术，对生长于大别山区的都支杜鹃（Rhododendron shanii Fang)的茎、叶进行了解剖学与环境适应性之间的关系研究。结果表明：叶的上表皮具有厚的角质膜、复表皮、气孔缺失；下表皮被毛，气孔分布密集，气孔突出；叶肉中栅栏组织和纤维丰富，且纤维呈束存在，并形成了叶肉中的支撑系统，海绵组织内具有发达的通气组织；茎中木栓宽广，次生韧皮部与次生木质部厚度比是1/5，次生木质部中管孔直径狭窄、管密孔集，绝大多数为管胞，同时木纤维十分丰富。上述结构的特异性均表明茎和叶在诸多方面表现为结构与环境的统一性，是特殊综合生态环境长期作用的结果。复表皮、主脉周韧维管束、次生木质部缺少导管等这些特征均说明都支杜鹃在系统分类中应处于较原始的地位。

Anatomy Features and Environment Flexibility of Rhododendron shanii Fang

The relationships between the anatomy and the adaptation to the environment for stems and leaves of Rhododendron shanii Fang growing in the Dabie Mountain area were studied by means of optical microdissection technology.The results show that there are thick cuticle and multiple epidermis and stomatal absence on the leaves’ epidermis;there are hair and distribution of prominent stomatal are serried under epidermis of leaves;there are abundance of palisade tissue and fibre in mesophyll,the fibre constitutes fiber bundle forming the skeleton system of mesophyll.Cork is wide in stem,the thickness ratio is 1/5 between the secondary phloem and secondary xylem;Most of pores with pores diameter stenosis and over disperse are the tracheid and moreover fibre is very rich in secondary xylem.All these features indicate that stems and leaves have unity of structure and environment in many aspects,such structural features results from adapting to environments.These features with multiple epidermis and amphicribral bundle of the main vein and vessel deficiency etc suggests that R.shanii is at the original position of the classification system.