Physiological Basis of Combined Stress Tolerance to Low Phosphorus and Drought in a Diverse Set of Mungbean Germplasm

Abstract

To understand the physiological basis of tolerance to combined stresses to low phosphorus (P) and drought in mungbean (Vignaradiata (L.) R. Wilczek), a diverse set of 100 accessions were evaluated in hydroponics at sufficient (250 μM) and low (3 μM) P and exposed to drought (dehydration) stress. The principal component analysis and ranking of accessions based on relative values revealed that IC280489, EC397142, IC76415, IC333090, IC507340, and IC121316 performed superior while IC119005, IC73401, IC488526, and IC325853 performed poorly in all treatments. Selected accessions were evaluated in soil under control (sufficient P, irrigated), low P (without P, irrigated), drought (sufficient P, withholding irrigation), and combined stress (low P, withholding irrigation). Under combined stress, a significant reduction in gas exchange traits (photosynthesis, stomatal conductance, transpiration, instantaneous water use efficiency) and P uptake in seed and shoot was observed under combined stress as compared to individual stresses. Among accessions, IC488526 was most sensitive while IC333090 and IC507340 exhibited tolerance to individual or combined stress. The water balance and low P adaptation traits like membrane stability index, relative water content, specific leaf weight, organic acid exudation, biomass, grain yield, and P uptake can be used as physiological markers to evaluate for agronomic performance. Accessions with considerable tolerance to low P and drought stress can be either used as ‘donors’ in Vigna breeding program or cultivated in areas with limited P and water availability or both.

Cross Tolerance to Drought and low Phosphorus Stress in Mungbean is Regulated by Improved Antioxidant Capacity, Biological N2-Fixation, and Differential Transcript Accumulation

“…PEPC and MDH are key enzymes in the TCA cycle; the metabolites of this pathway (citrate, malate, oxalate) are exuded into the rhizosphere under low P stress. We observed enhanced exudation of organic acids in IC333090, which corroborates with the expression pattern of genes regulating their synthesis (Meena et al 2021). Similar enhancements in the transcript level of PEPCase have been reported for white lupin (Uhde-Stone et al 2003) and soybean under low P stress.…”

“…This grouping was done based on extensive physiological studies where the accessions showed tolerance to individual stresses of drought, low P as well as to their combined stress (Meena et al 2021).…”

“…The mungbean accessions were grown in soil and subjected to four treatments: (1) control (su cient P, irrigated), (2) low P (no P, irrigated), (3) drought (su cient P, irrigation withheld), and (4) combined stress (no P, irrigation withheld). The experiment was conducted as mentioned in our previous report (Meena et al 2021). Seeds were sown during the summer season in earthen pots (30 cm diameter, 30 cm height) lled with sandy loam soil (pH 7.9, EC 0.155 mS m -1 ) with low available soil P (Olsen P 7.8 mg kg -1 soil).…”

Effects of Shade and Planting Methods on the Growth of Heracleum moellendorffii and Adenophora divaricata in Different Soil Moisture and Nutrient Conditions

“…The growth and survival of plants are normally associated with their ability to intercept light efficiently [ 28 ] and the amount of nutrients and moisture available in soil [ 29 , 30 ]. One significant finding of this study was that shading improved the height growth of H. moellendorffii in both unfertilized and fertilized plots and aboveground production in unfertilized ones.…”

High phosphorus supply enhances leaf gas exchange and growth of young Arabica coffee plants under water deficit

“…In fact, the cytosolic P i concentration controls the rate of photosynthesis and partitioning of photoassimilates between starch and sucrose (Rychter and Rao, 2005). While the scientific literature is rich when considering how low P supply affects plants (Partelli et al, 2009;Meena et al, 2021), little is known about how extra P supply may benefit plants under stressful conditions. Under nonlimiting conditions, coffee plants receiving extra P supply (twice the recommended) presented enhanced plant hydraulic conductance, leaf carbohydrate, and chlorophyll contents, resulting in improved growth as compared with trees supplied with the recommended P fertilization (Silva et al, 2010).…”