Anatomical structure characteristics of vegetative organs of endangered plant Calycanthus chinensis

The anatomical structure characteristics of vegetative organs(including root,stem,leaf and bud) of endangered plant Calycanthus chinensis W.C.Cheng et S.Y.Chang were observed by means of the paraffin method,and the relationship between these structure characteristics and ecological adaptability of C.chinensis was also discussed.The observation results show that the bud of C.chinensis is subpetiolar bud without bud scale.Primary xylem in root is triarch or tetrarch with more vessels whose diameter is big.And there are a lot of crystals in cortex and lignified parenchyma cells of root.The xylem of young stem contains more vessels with small sclerenchymatous cells on all sides and developed phloem fibres and pith.While the mature stem has protruding lenticels and epidermal hairs,and there are conglobate phloem fibres in every protruding parts.The leaf of C.chinensis is typical bifacial leaf and the anatomical characters are as follows: the leaf epidermis with thick cuticles;more crystals in epidermal and mesophyll cells;the stomata centralizing on lower epidermis of leaf and appearing T-shaped thickening in stomatal polar region;the palisade tissue being composed of one layer cell;the vascular bundles of primary vein being radial alignment and the vascular bundle sheaths in vein being thickened.It is suggested that the vegetative organs of C.chinensis have a certain primitive and drought tolerance structure characteristics.Meanwhile,those have some shade-tolerance anatomical characteristics,indicating that C.chinensis has a certain adaptability to shaded or valley habitats.