Research on structure of leaf epidermis of two species of Flos Lonicerae by SEM and its ecological adaptation

As an adaptive consequence,plants growing in drought habitats have developed various drought-resistant mechanisms on their leaf-structure such as well-developed epidermal hairs,conducting tissue and mechanical tissue. For finding valuable ecology-adoption characters,leaf epidermis of Lonicera japonica and L.confusa,which are in the genus of Flos Lonicerae were examined by scanning electron microscopes (SEM) to study the characteristics of stomata,trichomes and dermal cell,et al. To obtain more characters of morphology and anatomy of leaf,the optical microscopy was also used.The results showed that leaf epidermis consisted of epidermis cells and stoma complexes. On the lower epidermis,bushy trichomes including glandular hairs and non-glandular hairs are observed and some strumaes distributing regularly are hypothesized as oxalic calcium. In addition,the stomata apparatus are ruleless and only distribute on the lower epidermis. On the upper epidermis,anticlinal wall caves in sinuose groove to countercheck the transpiration. Evidences from leaf morphological structures sever as another proofs on drought-resistant mechanisms. L.japonica and L.confusa share typical xerophytic features and have bifacial leaves. Palisade tissues are well developed and cells of palisade tissue are cylindrical and cells of the spongy tissue are roundness. In addition,the conducting tissue and mechanical tissue are also well developed,which can improve the transportation efficiency of water. Therefore,the above characteristics of Flos Lonicerae can reduce the loss of water and make L.japonica and L.confusa adapt to the droughty environment at karst area in Southwest China. However,there is some difference of the two species. From the SEM result,it is shown that on the upper epidermis,some glandular hairs regularly present along the midrib of L.japonica,but L.confusa has no glandular hairs on the upper epidermis,which can verify the relationships of Flos Lonicerae species and provide the significance for classification of Flos Lonicerae.