Supplemental exogenous NPK application alters biochemical processes to improve yield and drought tolerance in wheat (Triticum aestivum L.)

Abstract

The recent food security issues, combined with the threats from climate change, demand future farming systems to be more precise and accurate to fulfill the ever increasing global food requirements. The role of nutrients such as nitrogen (N), phosphorous (P), and potassium (K) in stimulating plant growth and development is well established; however, little is known about their function, if applied in combination, in improving crop yields under environmental stresses like drought. The aim of this study was to evaluate the effects of combined foliar spray of supplemental NPK (NPKc) on physiological and biochemical mechanisms that enhance the drought tolerance potential of wheat for improved yield. Foliar NPKc markedly influenced the accumulation of osmoprotectants and activity of both nitrogen assimilation and antioxidant enzymes. It significantly improved the concentration of proline (66 %), total soluble sugars (37 %), and total soluble proteins (10 %) and enhanced the activity of nitrate reductase, nitrite reductase, catalase, and peroxidase by 47, 45, 19, and 8 %, respectively, with respect to no spray under water-deficit conditions which, in turn, improve the yield and yield components. The accumulation of osmolytes and activity of antioxidant machinery were more pronounced in drought tolerant (Bhakkar-02) than sensitive genotype (Shafaq-06).

Alleviation of Drought Stress by Nitrogen Application in Brassica campestris ssp. Chinensis L.

“…Total free amino acids were determined according to the method described by Shabbir R. N. et al [18] with slight modifications. For this, sample mixture containing 0.3 mL of the extract, 1 mL of pyridine (10%, w/v) and 1 mL of ninhydrin solution (3%, w/v), was heated in boiling water bath for 15 min.…”

Cross Talk between Nitric Oxide and Phytohormones Regulate Plant Development during Abiotic Stresses

“…Drought stress is one of the major limiting factors afecting multiple aspects of plant growth and productivity [2]. The typical mechanism of plants response to water stress, frequently caused by drought, is closure of stomata to conserve water.…”

“…Plants respond to such adverse conditions through perception of endogenous and exogenous stress factors via hormone signaling networks along with the coordination of several downstream signal transduction mechanisms involving cyclic nucleotides, calcium ions, and reactive oxygen (such as hydrogen peroxide) or nitrogen (e.g., nitric oxide) species. Acclimation to abiotic stresses is achieved through turgor maintenance [1], accumulation of osmolytes [2], regulation of photosynthetic and transpiration rate, and activation of antioxidant machinery [3]. Moreover, stress-induced alterations in gene expression and metabolism stimulate several anti-stress compounds, which help to modify physiology, phenology, growth, and reproduction of plants exposed to adverse environmental conditions [4].…”

Seed priming with KNO3 mediates biochemical processes to inhibit lead toxicity in maize (Zea mays L.)

“…It regulates ionic balance in cells and plays a key role in respiration and carbohydrate metabolism through the activation of the enzyme pyruvate kinase . Similarly, nitrogen is an essential element for healthy and vigorous plant growth at early growth stages . The positive role of KNO 3 seed priming against various abiotic stresses such as drought, salinity, high temperature and cadmium toxicity is well reported; however, reports regarding the possible effects of KNO 3 seed priming on growth and Pb accumulation in plant species are scant.…”