Paclobutrazole use as a tool for anticipate water stress response of sour passion fruit

Abstract

• Paclobutrazole (PBZ) applied in the molting phase promotes morphological and biochemical changes after transplantation. • Water stress promotes morphophysiological and biochemical changes in Passiflora edulis Sims plants. • The PBZ optimizes the exhaust mechanism under water stress. • Under excess water, low concentrations of PBZ result in greater water absorption and storage capacity in the tissues. • Low concentrations of the regulator protect isohydric expression under water restriction. • The growth restriction imposed by the regulator reduces the potential for biomass accumulation under water restriction. Water status such as drought or excess water, have led to great socio-economic impacts on sour passion fruit ( Passiflora edulis Sims) crops. Relevant studies have highlighted the impact of growth regulators on the activation and modulation of plant escape mechanisms to water stress. This study aimed to analyze whether PBZ affect morphophysiology and biochemistry of sour passion-fruit seedlings inducing a better adaptation to water stress after transplanting. In general, the irrigation regime was the factor that promoted the most expressive effect for all the evaluated characteristics, while the PBZ concentration factor affected only the morphology. The interaction between these factors was observed for leaf water potential (ѱ w ) and mass accumulation, characterized by increases as a function of increasing water availability. The 40 and 80 mg L −1 PBZ concentration induced the maintenance of higher ѱ w throughout the variation of water regime evaluated in this study, when it was determined at 140 days after emergence. The shifting from the quadratic model to the linear model of morphological characteristics as a function of the irrigation regimes, corroborates regulator effect to becoming it more directly associated with water availability, without interactions with other factors not addressed. The relationship between mass accumulation and PBZ concentrations were evidenced for the water excess regimes (90 and 120% pot capacity), characterized by decreases. Under water excess, 40 mg L −1 of PBZ results greater water uptake and storage capacity, increasing the plants' vigor. Although the anticipation of the escape mechanisms optimizes the plant's water status, the growth restriction imposed by the regulator reduced the biomass accumulation potential of the plants under water restriction.