Combined effect of cytokinin, paclobutrazoland ascorbic acid on nitrogen metabolism and yield of wheat (Triticum aestivum L.) under water deficit stress condition

Drought is the most significant factor restricting wheat production in the majority of agricultural fields not only in India but also in the world. A pot culture study was conducted to study the effect of exogenous application of cytokinin (TDZ), paclobutrazol (PBZ) and ascorbic acid (AsA) in combination on two contrasting wheat cultivars viz., HD 2733 and HD 2987 differing on the basis of their tolerance to drought. The results revealed that water stress condition leads to decrease in the activity of two main enzymes of nitrogen assimilation pathway i.e. nitrate reductase (NR) and glutamine synthetase (GS). Cytokinin, paclobutrazol and ascorbic acid application in combination enhanced the activity of both the enzymes across the cultivar and water regimes. Increase in level of total nitrogen was also found in treated plants under two water regimes. Protease activity was also found to be up regulated under water stress condition, which led to the degradation of protein, while treated plants showed significant reduction in the level of protease activity under stress condition. Yield related traits also showed significant reduction under water stress condition, while combined application of cytokinin, paclobutrazol and ascorbic acid enhanced the yield and its components.