Ecophysiological and genetic characteristics of three wetland plant species occurring in lake Victoria region in Kenya.

Abstract

This study was carried out to investigate the ecophysiological and genetic characteristics of some selected wetland plant species in Lake Victoria basin, Kenya. Seedlings of Cyperas esculentus L., Aframomum angustifolium (Sonn.) and Phragmites australis ((Cav.) Trin. Ex Steudel) were grown outdoors in pots. Plants were provided with four nutrient dosage levels of 0 mg [no fertilizer added], 50 mg, 100 mg, 150 mg fertilizer [N: P: K, 10:26:10] per pot and replicated five times. Data on Leaf area, number of tillers per pot, Leaf chlorophyll concentration, Gas exchange parameters and chlorophyll fluorescence parameters were determined. Separation of means was carried out to compare nutrient treatments and species. Increasing nutrient availability significantly (P≤0.05) influenced most of the morphological and physiological parameters investigated. Cyperas esculentus had significantly greater leaf area compared to A. angustifolium and P. australis. Number of tillers per pot was significantly increased in C. esculentus than in all other species, suggesting that this species was greatly influenced by nutrient availability than the other species. Phragmites australis had significantly higher carotenoids compared to the other species. Cyperas esculentus showed a higher photosynthetic activity compared to A. angustifolium and P. australis at increasing nutrient availability. Stomatal conductance increased with increase in nutrient availability in all the three species, but interestingly, P. australis and A. angustifolium had higher stomatal conductance compared to C. esculentus. Transpiration rates also increased with increasing nutrient availability but A. angustifolium and C. esculentus had significantly higher transpiration rates compared to P. australis. The study reveals Cyperas esculentus as a physiologically superior species compared to Aframomum angustifolium and Phragmites australis.