title: [Location and relative quantity of coumarins in the stem of Dendrobium thyrsiflorum].
abstract: OBJECTIVE
  To determine the location and relative quantity of coumarins in the stem of Dendrobium thyrsiflorum Rchb. f. , and to provide a scientific basis for evaluating and utilizing the famous medicinal plant.
  
  
  METHODS
  The stems of one, two and three years old, separately, were collected in February. Location and relative quantity of coumarins in the top, middle and basal parts of each stem sample were determined by using laser scanning confocal microscopy (LSCM). ANOVA and Tukey's test were employed in the statistical analysis.
  
  
  RESULTS
  The coumarins located mainly in vascular bundles, especially on the walls of the outer fiber cells. There was significant difference or great significant difference exist in every part of the stem from different ages. The values of significant difference were as follows: basal part P = 0.004 (< 0.01); middle part P = 0.009 (< 0.01); top part P = 0.036( < 0.05).
  
  
  CONCLUSIONS
  Two years old stem could be the best choice when collecting Dendrobium thyrsiflorum in Feburary.
authors.affiliation: School of Chinese Pharmacy Medicine, China Pharmaceutical University, Nanjing 210038, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zheng
authors.forename: Luo-shan
authors.initials: LS
authors.lastname: Xu
authors.forename: Zheng-tao
authors.initials: ZT
authors.lastname: Wang
authors.forename: Chao-ying
authors.initials: CY
authors.lastname: Zhang
mesh_terms: D003374:Coumarins / Q000032:analysis*; D031667:Dendrobium / Q000737:chemistry*; D018613:Microscopy, Confocal; D018547:Plant Stems / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D013997:Time Factors
chemical_list: D003374:Coumarins