Ecological functions of carbohydrates stored in corms of Tipularia discolor (Orchidaceae)

1. The orchid Tipularia discolor possesses two to five subterranean corms containing a high concentration of total non-structural carbohydrates (TNC). W e investigated the role of corms in the initiation of new growth following seasonal dormancy, in reproduction, and in the response of plants to artificial defoliation. 2. Severance of older corms (representing c. 3O0/0 of total corm biomass) influenced new shoot initiation, but had little o r n o effect on plants during fruit production o r in their response to defoliation. 3. Shading of plants during growth initiation had n o detectable impact on shoot growth o r storage use. Growth initiation caused a reduction in corm mass but n o change in per cent T N C in corms. Reproduction was associated with reductions in both corm mass and per cent TNC. 4. Artificial defoliation had little impact on the utilization of existing carbohydrate stores. 5. I t is concluded that carbohydrate storage in corms was relatively unimportant for the recovery of plants from herbivory in comparison to its role in growth initiation and reproduction.