Estratégias de mitigação do estresse hídrico em mudas de Talisia esculenta (A. St.-Hil.) Radlk

Abstract

Talisia esculenta (A. St.-Hil.) Radlk. (pitombeira, Sapindaceae) is a fruit tree with potential for food, timber, and forestry, but little is known about its water requirements. Thus, the objective of this study was to evaluate strategies for mitigating water stress in T. esculenta seedlings. Two independent experiments were conducted in which T. esculenta seedlings were subjected to water restriction (15 and 35 days) and flooding (15, 30, and 45 days), with these water treatments combined with the application of salicylic acid (SA - 200 mg L -1) and potassium silicate (K2SiO3 - 10.0 mL L-1). The experimental design was completely randomized in a split-plot factorial scheme. During water restriction, T. esculenta seedlings reduced photosynthetic metabolism and chlorophyll indices, increased proline content in leaves and roots, but there was no reduction in seedling growth. The use of salicylic acid and potassium silicate minimized the effects of water restriction and allowed for a longer period of tolerance to this condition, demonstrating their beneficial effects for up to 15 days. During flooding, T. esculenta seedlings survived and emitted hypertrophied lenticels, despite exhibiting lower photosynthetic activity. Potassium silicate, at the dose used, was more efficient than salicylic acid in mitigating the effects of flooding stress for 45 days on metabolic and growth characteristics. The use of salicylic acid was ineffective in the growth of flooded plants. T. esculenta was sensitive to water stress, both from deficit and flooding, but showed potential for resilience. The use of potassium silicate has the potential to mitigate stress, representing a strategy for seedling production under atypical environmental conditions for a determined period.