Implication of Jasmonic Acid on Physiological Alterations on Salt Stressed Fodder Sorghum (Sorghum bicolor L.)

Abstract

One of the main environmental factors that restricts the growth and productivity of sorghum is salt stress, which interferes with physiological processes including relative water content, NBI (nitrogen balance index), photosynthetic rate, etc. Agricultural land affected by soil salinity is growing significantly worldwide, therefore, strategies are needed to improve the salinity tolerance and most efficient one can be opted by studying the response of sorghum against salinity. Salt stress can be reduced by plant stress hormones such jasmonates, ABA, brassinosteroids, etc. In order to assess the effects of jasmonic acid (JA) (4.5, 6.5 & 8.5 mM) on the physiological properties of sorghum (HJ 541 and CSV 21F) grown in saline soil (4, 6 & 8 dS/m), green house experiment was executed on a complete randomized design (CRD), with three replications. The results shows that the salinity adversely effected photosynthetic efficiency, chlorophyll content, antioxidants (anthocyanin and flavonoids), nitrogen balance index, ash content which can be used as the most suitable parameter for determining tolerance to salinity stress. While, foliar application of jasmonic acid significantly improved the relative water content, chlorophyll content, photosynthetic rate, stomatal conductance, etc. Jasmonic acid concentrations of 8.5 mM had more noticeable effects. Percent enhancement in chlorophyll index, transpiration rate, stomatal conductance, was 14.5% and 13.4%, 16.7% and 19.9%, 42.0% and 58.0% in HJ 541 and CSV 21F, respectively at 8 dS/m as compared to control.  CSV 21F performed better as compared to HJ 541 at all levels of salt stress after application of jasmonic acid.