Crescimento e conteúdo de solutos orgânicos em couve-flor cultivada com água salobra em sistema hidropônico

Abstract

Organic osmolytes compatible with cellular metabolism play a fundamental role in the acclimatization of plants under conditions of abiotic stress. Therefore, the objective of the present study was to evaluate the content of soluble carbohydrates, total free amino acids, soluble protein, and free proline in the cauliflower leaves and inflorescence at different developmental stages, under salt-stress in hydroponic conditions. The experimental design was in randomized blocks with six levels of electrical conductivity of the nutrient solution - ECsol (1.7, 5.3, 7.4, 9.6, 11.2, and 12.9 dS m-1) and five replications. The results obtained show that the salt stress affects the fresh and dry mass of the aerial part and contents of organic solutes in the leaves at 30 and 60 days after transplanting (DAT). There was a reduction in the soluble carbohydrate contents in the leaves at 60 DAT as the salinity increased. For the contents of free amino acids, soluble proteins, and free proline in the leaves a reduction was observed up to a certain level of water salinity, increasing at the highest levels, mainly free proline. In the inflorescence, the contents of organics solutes had a greater increase in comparison to the leaves under ECsol 12.9 dS m-1. Overall, organic solutes did not contribute to the osmotic adjustment as a response to salt stress, but at higher levels of ECsol 9.6, 11.2, and 12.9 dS m-1, may have contributed to mitigating the effects of salts in the cauliflower plants.