Paclobutrazol alleviates seed germination and growth inhibition in Amorpha fruticosa under PEG-induced drought stress

An in-depth quantitative analysis of the relationships between plant functional and physiological characteristics in arid areas will help to explore the response of xerophytic shrubs in the desert. Therefore, it is necessary to study the vegetation in arid areas. Through artificial intervention, exploring whether the medicament (Paclobutrazol, Pbz) can improve the adaptation of plants to the arid environment. In this study, the Amorpha fruticosa seeds soaked by Pbz at various concentrated applications at 150, 300, 450, and 600 mg/L (T1, T2, T3, T4) and then to explore the optimum concentration of drought-stress resistance. The results showed that seed germination was increased by 35.2% (p < 0.05) after 450 mg/L (T3) Pbz immersion compared with the control. Under mild drought stress, the seedling growth height and leaf area were reduced by 28.8% and 54.3%, then the stem diameter and seedling weight were increased by 1.6 and 2.4 times, respectively. Pbz significantly increased POD activity, SOD activity, Chlt content and Ss content (p < 0.05). However, it significantly inhibited the MDA content (p < 0.05). The combined effect showed that Pbz solution significantly improved seed germination quality, while effectively alleviating drought stress on seedlings and delaying plant growth, with the best treatment of T3.