Physiological Responses of Bambara Groundnut (Vigna subterranea L. Verdc) to Short Periods of Water Stress During Different Developmental Stages

摘要

The study was conducted to evaluate the responses of bambara groundnut (Vigna subterranea L. Verdc) to short periods of water stress imposed at different growth stages, and the recuperative ability of the species from drought stress. A major problem associated with Bambara groundnut production is its very low yields due to intra-seasonal and inter-seasonal variability in rainfall in semi-arid regions. The response pattern of physiological processes to water stress imposed at different growth stages might provide a basis for development of strategies in order to stabilize yields. Water stress reduced relative w ater content, chlorophyll fluorescence, stomatal conductance and the reduction was more pronounced in plants stressed during the pod filling stage and less pronounced in plants stressed during the vegetative stage. Chlorophyll content was not affected by water stress at all stages of grow th and development. Proline levels were increased by water stress mostly during the pod filling stage. When plants were rewatered after each stress treatment, plants stressed during the pod filling stage failed to fully recover the relative w ater content and chlorophyll fluorescence. A ll water stressed plants at different stages of growth and development fully recovered in stomatal conductance and proline concentration. Bambara groundnuts appear to reduce water loss under water stress and have the ability to recover from the effects of water stress after rainfall or irrigation. The nature and extend of damage and the ability of bambara groundnut to recover from water stress depends on the developmental stage at which the plant encounters water deficit.