Flax ( Linum usitatissimum L.) is one of the drought sensitive crops and its production under water deficit conditions is challenging. The objective of this research was to assess the effectiveness of individual and synergistic treatments of different concentrations of salicylic acid, indole acetic acid and moringa leaf extract to enhance drought resilience in flax. A pot experiment was conducted with a completely randomized design with three replicates comprising 12 treatments with various concentrations of salicylic acid (SA), indole acetic acid (IAA) and moringa leaf extract (MLE), both individual and in combination. Among the tested treatments, the synergistic treatments proved to have better results in mitigating the adversities of drought than the alone. Primarily, 3% moringa leaf extract (MLE) treatment with various concentrations of indole acetic acid (IAA) (2 and 4 mgL − 1 ) and SA (0.5 and 1.0 mM) proved to be one of the promising mitigators for flax under drought stress and helped in improving a number of plant parameters. The treatment of 3% MLE and 2 mgL − 1 IAA, resulted in highest shoot length (87.63 cm), while treatment of 3% MLE + 0.5 mM SA (T10) showed the highest number of leaves (188.33). Highest leaf relative water content (105.96%), number of seed capsules and seed yield was observed at 3% MLE and 4 mgL − 1 IAA (T13). MLE at 3% + IAA 4 mgL − 1 (T13) exhibited highest chlorophyll contents (69.53 SPAD units). In case of phytochemical parameters, highest value of phenolic compounds (7.20 mg GAE g − 1 of fresh weight) was observed at 3% MLE + 1.0 mM SA (T11). At 3% MLE + 2 mgL − 1 IAA (T12) highest flavonoid content (0.51 mg CatE g − 1 of fresh weight) was observed and at 3% MLE + 0.5 mM SA (T10) highest proline contents (13.83 µmol g − 1 ) was observed. These results support the positive and surpassing role of MLE in combination with SA and IAA in flax under drought stress.
Ahsan et al. (Fri,) studied this question.