Carbon, Nitrogen and Phosphorus Ecological Stoichiometry Traits of Dendrobium officinale Organs in Different Growth Stages

To reveal the characteristics of ecological stoichiometry of carbon (C), nitrogen (N), phosphorus (P) in the stems and leaves for different seasons, the contents of C, N, P and their ecological stoichiometry were studied in Dendrobium officinale with good cultivation traits.The results show that the variation coefficients of C, N and P contents in stems are 13.71%, 24.99% and 29.71% respectively, while they are 4.99%, 9.83% and 10.42% in leaves.The variation coefficients of C/N ratio, C/P ratio and N/P ratio in stems are 34.38%, 46.53% and 21.13% respectively, while they are 11.15%, 13.20% and 8.54% in leaves.The contents of nitrogen in the stem and leaf are significantly positively correlated to the content of phosphorus respectively.The value of N/P ratio is mainly associated with P content.From March to May, the high value of C/N ratio and C/P ratio indicate that it is the best period for harvesting D.officinale.The contents of C, N and P and the ecological stoichiometry in the stems of D.officinale vary greater than those in the leaves with the seasonal variation.Therefore, the contents of C, N and P in the stems are important index for evaluating the nutrient change of D.officinale and obtaining the highest carbon benefit.