Vegetative anatomy of the rare plant Cypripedium japonicum Thunb.

Abstract

The anatomical structure of vegetative organs of endangered plant Cypripedium japonicum Thunb. were studied by means of paraffin sections. The results show that a large number of starch granules exist in the parenchyma cells of rhizomes,amphivasal bundles are distributed compactly in the vascular cylinder; the cortex covers most of the root cross-section,radially arranged groups of xylem and phloem alternate with each other in vascular cylinder,mycorrhizal fungi form pelotons in the cortical cells,the endodermis cells in both rhizome and root show horseshoe 一 shaped thickening; stomates occur on the surface of the stem,the cortex is relatively narrow,but the inside ground parenchyma is well developed,and collateral bundles are distributed scatteredly through it,nonglandular trichomes are associated with the surface of the stems and leaves; the leaves are isobilateral,mesophyll cells are arranged loosely,stomata which are mostly found on the abaxial surfaces extruded slightly outside the epidermis,chloroplasts and air cavities are found respectively in the guard cell and mesophyll of leaf margin. The anatomical characteristics mentioned above are adapted to their living environment.