Stress index, water potentials and leaf succulence in cauliflower cultivated hydroponically with brackish water

Índice de estresse, potenciais de água e suculência foliar em couve-flor cultivado hidroponicamente com águas salobras

ABSTRACT

The tolerance of crops to salinity is greater in hydroponic systems due to the low contribution of the matric potential to the total potential of the water. The objective of this study was to evaluate the use of brackish water, to prepare the nutrient solution and replace the evapotranspired volume, and rates of application of this solution on the water stress index, water potential, leaf succulence and water consumption of cauliflower cv. ‘Piracicaba Precoce’. The experimental design was completely randomized in a 6 x 2 factorial scheme, with six salinity levels used to prepare the nutrient solutions (0.2, 1.5, 2.5, 3.5, 4.5 and 5.5 dS m^-1) and two application rates of these solutions (1.5 and 2.5 L min^-1), with four replicates. Water stress index (WSI), water and osmotic leaf potentials, leaf succulence (LS) and water consumption were analyzed. The increase in water salinity reduced LS and increased WSI. Water salinity reduced the water and osmotic leaf potentials and water consumption of the crop; however, the effects were more pronounced at the rate of 2.5 L min^-1. Application rate of 2.5 L min^-1 led to the highest WSI and lowest LS.

Key words:
water relations; hydroponics; salinity