OBJECTIVETo study the distribution and dynamic change of coumarins in the leaf and root of Dendrobium thyrsiflorum at different developmental stages, and provide an experimental evidence for utilizing the medicinal plant.

METHODThe leaf and root materials were collected at vegetative and reproductive stage. By applying laser scanning confocal microscopy, relative quantity of coumarins of each sample was observed and analyzed.

RESULTCoumarins located in D. thyrsiflorum leaf except fibers in vascular bundles which were close to the upper or lower epidermis. Coumarins were found in D. thyrsiflorum root structure at different developmental stages and walls of cells within cortex were especial appropriate places for the components distribution. Relative quantity of coumarins was changed obviously when plant was growing. The components reached the highest level during profuse flowering period whereas there were less coumarins at vegetative period and little during initial fruit period.

CONCLUSIONIn order to utilize D. thyrsiflorum reasonably and thoroughly, coumarins should be extracted from the plant leaf and root.