Ácido salicílico e prolina como indutores de tolerância a estresse hídrico em feijão-caupi

Abstract

The use of salicylic acid and proline may mitigate the deleterious effects of water deficiency on plants. Therefore, the research aims to evaluate in field conditions the effect of salicylic acid and proline on stress attenuation due to water deficiency in cowpea (Paulistão genotype) in its phenological period V5. The experimental design was completely randomized using the 2 x 4 factorial scheme in a five replicate system. The factors were constituted by two irrigation slides: 100% of the evapotranspiration (W100) and 50% of the evapotranspiration (W50) and four treatments: Control, AS (550 mg L^-1), Proline (690 mg L ^-1) and Proline + AS (690 mg L^ -1 proline and 550 mg L^ -1 AS). Water, growth and biochemical status assessments were performed to elucidate the effects of stress under these parameters. Under water restriction during the seven day period, the genotype did not present a significant difference for the water status variables (CRA and U%). This non-differentiation was possibly due to the marked increase in the variables PRO, total soluble sugars ) and water soluble proteins (PST) that have been shown to be responsive to stress and the different sources of attenuation. Growth was affected by water restriction however the use of proline and Proline + AS contributed to a better development of the plant even under these conditions. The activity of the CAT enzyme was enhanced water deficit and by the use of the attenuators Proline and Proline + AS. The activity of the SOD and APX enzymes was reduced with the use of attenuators, possibly by the non-enzymatic action of removing ROS. The compounds Proline and Proline + AS diminished the damages caused by the water deficiency since the plants submitted to them presented the best responses in relation to the development and accumulation of compatible osmolytes, the AS promoted increase in the increase of the activity of enzymes under water deficiency.