Nitrogen Use Efficiency Regulates Drought Stress in Pearl Millet Genotypes: Morpho-Physiological Evaluation

In this paper, the author discusses the effects of drought stress on pearl millet genotypes during the vegetative stage of development and the plant's mechanisms for survivability under stress with various nitrogen treatment regimes. A total of six treatment conditions were imposed on plants, i.e., N0 (no Nitrogen-0 mM), N0+PEG-10%, LN (low Nitrogen-2.5 mM), LN+PEG-10%, HN (high Nitrogen-7.0 mM), and HN+PEG-10%. Five days of moderate drought stress caused significant morphophysiological changes, as evidenced by a reduction in fresh and dry biomass, as well as relative water content (RWC), relative electrolyte leakage, and chlorophyll fluorescence,. A significant reduction in plant biomass and RWC when compared to the controls was seen. Reactive oxygen species (ROS) and lipid peroxidation (MDA) levels increased in the shoot in response to drought stress along with a loss of membrane integrity. A nitrogen treatment regime regulated the drought stress. In relation to N0-treated batches, proline accumulation increased in various N-treated batches. Results revealed that GHB-538 is less tolerant to drought stress in different N treatment conditions, while RHB-234 and 223 showed better tolerance to drought under nitrogen treatments. The significance of this study is to uncover the regulatory role of nitrogen over the drought stress in pearl millet.