Physiological responses of mango (Mangifera indica) rootstock seedlings to water stress

Water stress affects plant growth and crop productivity in the vast semi-arid and arid regions of Kenya. The present study was aimed at investigating the effect of different watering regimes on the growth of young mango rootstock seedlings. Six months old mango (Mangifera indica) rootstock seedlings were grown in polythene pots in a green house at Maseno University, Kenya and were subjected to four watering regimes namely watering daily, twice in a week, once in a week and once in two weeks. Treatments were in a completely randomized design replicated six times. The physiological parameters determined were stomatal conductance, transpiration rate, CO2 assimilation rate and intercellular CO2 concentration, all determined by infra red gas analyser and leaf chlorophyll content determined by standard methods. The results showed that increasing water stress reduced the physiological parameters particularly at the later days of plant growth, due to stomatal and non-stomatol factors. Leaf chlorophyll content however, chlorophyll content was slightly increased since the chrophyll pigments may have been resistant to dehydration. It was concluded that increase in water stress reduces the gas exchange parameters of mango rootstock seedlings but slightly increased chlorophyll content.