Biochemical responses of water-stressed triticale (X Triticosecale wittmack) to humic acid and jasmonic acid

Abstract

The efficacy of humic acid (HA) and jasmonic acid (JA) application to modulate the adverse effects of water stress on pigment content, relative water content (RWC), antioxidant enzyme activity, and ion balance of two triticale genotypes (ET-83-3 and ET-84-8) was investigated in a pot experiment under controlled conditions. Application of both HA and JA in ET-84-8, increased chlorophyll a and b content 19.9 and 21% under water stress, respectively. Carotenoid content was also increased from 7.7 mg/g fresh weight to 9.5 mg/g fresh weight under water stress. Furthermore, catalase (CAT) and peroxidase (POD) activities and proline content were increased 34.8%, 13% and 99.5%, respectively when ET-84-8 genotype was exposed to HA and JA together. RWC of water-stressed plants was lowered in both genotypes however, the decreasing rate was greater in ET-84-8genotype. Higher K‏+ accumulation in water-stressed ET-84-8 genotype was accompanied by an increase in pigment content, CAT and POD activity as well as RWC. There was a negatively significant relationship between the main shoot grain yield and the malondialdehyde (MDA) activity. Significant and positive relationships were also found between the main shoot grain yield with CAT activity as well as RWC. Overall, it was found that concomitant foliar application of HA (1.0 mM) with JA (50 µM) was able to alleviate the inhibitory effects of water stress in the ET-84-8 genotype via enhancing proline content, CAT and POD activity, and lowering MDA.