Leaf epidermal characters of Lonicera japonica and Lonicera confuse and their ecology adaptation

Abstract

The leaf epidermis of Japanese honeysuckle (Lonicera japonica Thunb.) and Wild Honeysuckle (Lonicera confusa) in the genus of Flos Lonicerae were mainly observed by scanning electron microscopes (SEM) to study the characteristics of stomata, trichomes and dermal cell, etc.. The results showed that stoma exists only on the lower epidermis and its distribution is irregular, and leaf epidermis consist of epidermis cells, stoma complexes and bushy trichomes including glandular hair and non-glandular hair. On the upper epidermis, anticlinal wall caves in sinuous groove to countercheck the transpiration. Evidences from leaf morphological structures serve as another proof on drought-resistant mechanisms. Some strumaes distributing regularly are hypothesized as oxalic calcium on the lower epidermis under laser scanning confocal microscopy (LSCM) with Fluo-3/AM, which can increase their endurance to drought stress. Therefore, the above characteristics of Flos Lonicerae can reduce the loss of water and make Japanese honeysuckle and Wild Honeysuckle adapt to the droughty environment at Karst area in southwest China. However, there is some difference of the two species. From the SEM (Scanning Electron Microscopy) result, it is shown that on the upper epidermis, some glandular hair regularly present along the midrib of Japanese honeysuckle, but Wild Honeysuckle has no glandular hair on the upper epidermis, which can verify the relationships of Flos Lonicerae species and provide the significance for classification of Flos Lonicerae.