Exogenous ascorbic acid application ameliorates drought stress through improvement in morpho-physiology, nutrient dynamics, stress metabolite production and antioxidant activities recovering cellulosic fibre production in jute (Corchorus olitorius L.)

Drought is known to alter the physiological responses in plants affecting their growth and development. Jute (Corchorus olitorius L.), an important lignocellulosic fibre crop, is susceptible to drought stress at early growth stage. Limited information on plants’ response to early drought and its mitigation are available in jute. Here, we investigated early drought response in contrasting jute genotypes and focused on drought mitigation using different plant growth regulators to identify the best growth regulator and genotypic combination. Comparative effect of these plant growth regulators showed that 10 mM ascorbic acid aided in maximum drought recovery. Drought arrested biomass yield (72%) and plant height (16.3%), reduced leaf number (44.7%) and chlorophyll content (41.9%), affected nutrient (N, P, K, Fe and Ca) uptake and modified the cell wall composition reducing fibre productivity and quality. Drought enhanced biosynthesis of proline, ascorbic acid, flavonoids and antioxidants coupled with increase in endogenous ascorbic acid. Endogenous ascorbic acid exhibited significant correlation with more traits (25) under drought compared to control (11 traits). Exogenous ascorbic acid resulted in recovery of plant height (6.5%), fresh biomass (17.25%), dry biomass (6.0%), fibre cellulose (60.2%), total chlorophyll (31.2%), N (10.5%), P (18.1%), K (5.7%), Fe (44.6%), Ca (31.3%) and membrane stability (70.69%) whereas proline content was reduced up to 9.6 times. With exogenous ascorbic acid application, the endogenous ascorbic acid increased by 14.4% exhibiting significant positive correlation with 22 traits. The drought tolerance of genotypes, cv. JRO 204, is attributed to higher endogenous ascorbic acid, proline, nutrient content and anti-oxidants which contributed to higher cellulose in fibre and biomass. Hence, the cultivation of drought tolerant genotype supplemented with exogenous ascorbic acid can be a robust mitigation strategy for early drought management in jute.