Biomass and Nutrient Allocation of Tipularia Discolor (Orchidaceae)

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Abstract
T. discolor (Orchidaceae) plants were sampled in a deciduous forest in Maryland [USA] to determine how biomass and nutrients were allocated to different plant structures during an annual cycle. Corms older than 1 yr lose weight gradually during the year and most vegetative growth goes into current year corms. Leaves and sexual reproductive structures account, at peak biomass, for .apprx. 20% of the total plant biomass. The largest percentages of macronutrients (N, P, Mg, Ca, K) and micronutrients (Fe, Al, B, Sr, Mn, Zn, Cu, Pb) were found in corms 2 yr and older, and nutrient concentrations were also high in newly formed leaves and inflorescence. Analysis of the biomass and nutrient data suggest that translocation is important, but that it does not account for all of the uptake in new growth. Plants must, therefore, assimilate nutrients from the soil during periods of growth. The importance of large underground storage structures is discussed.