Effect of Potassium on Salinity Tolerance of Mungbean (Vigana radiata L. Wilczek)

It is established that salinity disturbs mungbean plant growth by creating nutrient imbalance and disturbance in plant water relations. This study was undertaken to observe whether external application of K mitigates the harmful effect of salinity. Mungbean plant (var. BARI mung 3) was grown in pot at three levels of K viz. 14, 40 and 60 kg ha ha-1 under 0 and 75 mM NaCl saline conditions. Salinity decreased seriously relative water content and water retention capacity, while increased water saturation deficit and water uptake capacity. Salinity also decreased xylem exudation rate and leaf water potential. Application of higher amount of K improved the plant water relationship in mungbean plant. Salinity disturbed dry matter distribution in different plant parts as well decreased total dry matter. Similarly yield and yield contributing characters were also seriously affected by salinity, except number of seeds per pod. Application of different levels of potassium did not influence on dry matter production. However, yield and yield contributing characters were improved to some extent with the increasing levels of K. Salinity decreased significantly the uptake of N, P, K and Ca, while increased Na uptake several fold. Mg accumulation was unchanged due to salinity. K doses had no significant influence on nutrient uptake by mungbean plant, though the uptake of most of the nutrients showed an increasing tendency with the increased levels of K application. It was concluded that application of higher levels of K improves water relations as well as growth and yield of mungbean under mild level of saline conditions.