Exploration of physiological and biochemical processes of canola with exogenously applied fertilizers and plant growth regulators under drought stress

Abstract

Environmental stresses may alter the nutritional profile and economic value of crops. Chemical fertilizers and phytohormones are major sources which can enhance the canola production under stressful conditions. Physio-biochemical responses of canola altered remarkably with the use of nitrogen/phosphorus/potassium (N/P/K) fertilizers and plant growth regulators (PGRs) under drought stress. The major aim of current study was to evaluate nutritional quality and physio-biochemical modulation in canola (Brassica napus L.) from early growth to seed stage with NPK and PGRs in different water regimes. To monitor biochemical and physiological processes in canola, two season field experiment was conducted as spilt plot under randomized complete block design (RCBD) with four treatments (Control, Chemical fertilizers [N (90 kg/ha), P and K (45 kg ha-1)], PGRs; indole acetic acid (IAA) 15g ha-1, gibberellic acid (GA3) 15g ha-1 and the combination of NPK and PGRs] under different irrigations regimes (60, 100, 120, 150 mm evaporations). Water stress enhanced peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), polyphenol oxidase (PPO), soluble sugar, malondialdehyde (MDA), proline contents as well as leaf temperature while substantially reduced leaf water contents (21%), stomatal conductance (50%), chlorophyll contents (10–67%), membrane stability index (24%) and grain yield (30%) of canola. However, the combined application of NPK and PGR further increased the enzymatic antioxidant pool, soluble sugars, along with recovery of leaf water contents, chlorophyll contents, stomatal conductance and membrane stability index but decreased the proline contents and leaf temperature at different rate of evaporation. There is positive interaction of applied elicitors to the water stress in canola except leaf area. The outcomes depicted that the combination of NPK with PGRs improved the various morpho-physiological as well as biochemical parameters and reduced the pressure of chemical fertilizers cost about 60%. It had also reduced the deleterious effect of water limitation on the physiology and grain yield and oil contents of canola in field experiments.

Interaction between Rhizobacteria and Andrographis paniculata Under Water Limitation

“…On the other hand, under drought stress conditions the relative water content decreased when compared to normal irrigation as a control treatment (T1). A similar result was presented by Aslam et al (2021), who found a reduction in leaf water content when using chemical fertilizer alone under severe evaporation for improved Canola growth, decreasing relative water content as a result of water limitation. In contrast, the application of microbial biofertilizer (PGPR) maintained relative water content in plant leaves.…”

Proline Enhances Resistance and Recovery of Oilseed Rape after a Simulated Prolonged Drought

“…There is no doubt that one of the most important changes in metabolic functions during drought is the loss of photosynthetic pigments or a decrease in their synthesis. Numerous studies have reported that drought-induced oxidative stress significantly reduces chlorophyll content in crop plants [ 28 , 34 , 35 , 40 ]. This was also confirmed by the data of our study, which showed that moderate and severe drought stress significantly reduced the content of chlorophyll a, b compared to control plants ( Table 4 ).…”

“…Similar drought-induced oxidative stress was recorded in oilseed rape plants in studies by other authors [ 28 , 34 , 36 ]. Excessive concentrations of free radicals, including H 2 O 2 , can cause damage to cell membranes, ion leakage, and osmotic imbalance, so maintaining their level is very important [ 34 , 40 ]. Plant spraying with exogenous proline significantly reduced H 2 O 2 content in prolonged-drought-stressed rapeseed leaf tissues.…”

Factors Affecting the Quality of Canola Grains and Their Implications for Grain-Based Foods

“…Adequate soil fertility can lead to better plant growth and yield and higher oil content [75,76]. Adequate soil fertility can lead to better plant growth and yield and higher oil content [77,78]. However, excessive use of fertilizers can lead to the accumulation of nitrates in B. napus seeds, which can be harmful to human health [79].…”