Brazilian Journal of Botany | 2021
2,4-Epibrassinolide mechanisms regulating water use efficiency and fruit production in tomato plants
Abstract
Tomato (Solanum lycopersicum L.) plants are able to adapt to restrictive environmental conditions mainly due to hormones such as brassinosteroids (BRs) that play important roles in determining stomata conductance and leaf transpiration. However, BRs effects on morphological traits like stomata and trichome position, size, and density, as well as on physiological traits resulting in better plant water use efficiency (WUE) and productivity, remain poorly understood. The objective of this study was to better understand the 2,4-epibrassinolide (EBL) mechanisms regulating leaf transpiration and WUE that can affect fruit production in tomato plants. According to results, treating tomato plants with exogenous EBL resulted in lower leaf transpiration, mainly from 9 to 16\xa0h during the day, as well as lower stomata conductance and aperture, higher leaf water potential, higher net CO2 assimilation rate, higher number of stomata and trichome on leaf abaxial and adaxial surfaces, and higher plant dry mass accumulation, which improved plant WUE, compared to non-treated plants. EBL treatment also increased fruit size, fruit production per plant, and fruit quality traits such as higher dry mass and soluble solids content. In conclusion, BRs can improve plant adaptation to water stress conditions by regulating important physiological and morphological mechanisms, controlling plant WUE, and leading to higher fruit production.