Effect of salinity stress on growth and nutrient uptake in polyembryonic mango rootstocks

摘要

Six-month-old, uniform-sized seedlings of seven mango (Mangifera indica L.) rootstocks namely Moovandan, Bappakai, Nekkare, Kurukkan, Clour, Terpentine and Chandrakaran were irrigated to 70% of field capacity with water containing 0, 50, 100, and 150mM NaCI for 90 days. Growth in terms of plant height, number of leaves and leaf area per plant decreased with increasing levels of salinity in all rootstocks. The decrease in growth was greatest in the salt-susceptible Chandrakaran rootstock (32.02%) athigher levels of salinity. However, in the salt-tolerant Clour and Nekkare, NaCI caused only a slight decrease in numbers of leaves and leaf area per plant. A declining trend was observed in fresh and dry weight of plant with increasing concentration ofNaCI in all rootstocks and maximum decrease was found in Chandrakaran (73.43% In shoot and 57.20% in root) whereas minimum was in Clour. The concentration of Na* ions in leaf tissues increased to a maximum (123.53%) in Chandrakaran and in root tissues Bappakai had the highest Na^ ions (77.27%) content. The maximum increase (109.09%) in leaf Cl' ions level occurred in Moovandan and Chandrakaran had the highest (139.29%) root C|-ions content at 150 mM NaCI. These data suggest that lower levels of Cl' andNa~+ accumulation could be used as indicators for screening mango rootstocks for resistance to NaCI stress. Clour, Terpentine and Nekkare can exclude Cr ions; however, Kurukkan, Bappakai, and Moovandan rootstocks seems to be Na~+ excluder upto lower level of salt concentrations. Based on overall performance and leaf scorching, it could be said that salinity tolerance increased in the following order Chandrakaran < Moovandan < Bappakai < Nekkare < Kurukkan < Terpentine < Clour.