Ameliorating effects of exogenous paclobutrazol and putrescine on mung bean [Vigna radiata (L.) Wilczek] under water deficit stress

Plant growth regulators play crucial roles in modulating plant response to environmental stresses. In this experiment, the effect of different doses of paclobutrazol (PBZ) and putrescine (Put), i.e., 0, 50, 100 and 150 mg/L on mung bean in two conditions of water deficit (WD) and well-watered (WW) was investigated. The seed yield decreased due to water deficit stress, while the PBZ and Put application alleviated the damage of drought stress through increasing proline and leaf chlorophyll content and improving membrane stability, and thus increased plant yield compared to untreated control plants. According to regression equations, the high PBZ levels (150 mg/L or more) and moderate levels of Put (about 90 mg/L) were determined as the optimal concentrations to maximise mung bean yield in WD conditions. In WW conditions, the mung bean responses to PBZ were inconsistent, whereas Put application positively affected some physiological traits and seed yield. In conclusion, the physiological attributes and, subsequently, the seed yield of drought-stressed mung bean plants could be improved by foliar application of PBZ and Put.