Comparative Carpology of South Indian Rauvolfia Species

摘要

Morphology and physiology of fruit and seed development were compared in five south Indian Rauvolfia species viz., R. hookeri, R. mierantha, R. serpentina, R. tetraphylla and R. verticillata. Drupes being a sole propagule of Rauvolfia among Apocynaceae, study on fruit development and phenology has become relevant for establishing species conservation. Phenology of flowering/fruiting spreads almost thromughout the year in R. hookeri, R. mierantha and R. tetraphylla and it was found from February-September and from February-October, respectively in R. serpentina and R. verticillata. Rauvolfia hookeri, R. mierantha and R. serpentina took 6 weeks after anthesis (WAA) while R. tetraphylla and R. verticillata took 10 and 8 WAA to develop into mature drupes. All the species followed a sigmoidal pattern in morphological as well as physiological characters of fruit/seed development. The single-sigmoidal growth curve for increase in fruit length of all the species differs from the double-sigmoidal one of R.tetraphylla. Rauvolfia hookeri and R. mierantha followed single-sigmoidal pattern in fruit and seed dry mass accumulation while others followed double-sigmoid pattern. But the dry matter accumulation continued till full ripening in fruits and it almost completed in seeds of R. hookeri, R. mierantha and R. verticillata. The inferences on fruit set and related issues like dry matter allocation among seed components, purity and cues on the harvestable maturity of fruits/seeds may amugment species conservancy.