Aspectos fisiológicos em soja tratada com brassinosteroide e submetida a déficit hídrico no estádio vegetativo

Abstract

Soybean (Glycine max (L.) Merrill) is a legume that is widely used in the market, as it can be used both in the food production agroindustry and in feed production, where it is highlighted for its high protein value. In addition, it is used for the production of biofuels, having a great prominence in the world economy. However, water deficit can be one of the major limiting factors for the development of this crop. Thus, the present work seeks to understand how the use of the bioregulator brassinosteroid can influence the attenuation of the effect of water deficit in soybean plants. Soybean plants that received different concentrations of brassinosteroids (0, 50, 100, 150 and 200 nM) were evaluated in the seeds that were later sown in pots in a greenhouse and submitted to water deficit. Brassinosteroid promoted positive responses in the plant, as the application of the hormone allowed a mitigation of damage caused by water deficit, when compared to treatments where the bioregulator was not used. The 100 nM concentration was considered the ideal concentration to be used in the preparation of soybean seeds, as it resulted in increased photosynthetic CO2 assimilation, relative water content, stomatal conductance, transpiration, water use efficiency, carboxylation efficiency and total dry mass, in addition to reducing internal carbon concentration in the leaf, when compared to plants without brassinosteroid application.