THE IMPORTANCE OF SALICYLIC ACID IN THE MITIGATION OF WATER DEFICIT IN COFFEE PLANTS

Abstract

Water stress in plants can be mitigated through the application of eliciting substances that stimulate different defense physiological responses in plants. The aim of this study was to evaluate the effectiveness of salicylic acid (AS) as a pre-activator of the water deficit defense system to growth and photosynthetic characteristics of coffee plants. The work was carried out in a greenhouse covered with transparent plastic and sides with a screen that intercepts 50% of solar radiation. The experimental design was completely random in a 6 x 2 factorial arrangement, with six concentrations of AS (0.0 mM, 0.05 mM, 0.1 mM, 0.2 mM, 0.4 mM and 0.8 mM) and two cultivars of coffee plant (IPR 100 and Tupi) with five repetitions. The AS was supplied at 100, 120 and 140 days after emergence (DAE) through foliar application. At 135 DAE, all plants were submitted to 10 days of severe water deficit with total suspension of irrigation. At 145 DAE, growth variables, photosynthetic pigments, relative water content and perspiration rate were evaluated. AS in concentrations between 0.05 to 0.8 mg L^-1 led to reduced growth and accumulation of biomass in coffee cultivars. The AS didn’t activate the defense mechanisms of coffee plants under water deficit and the tested concentrations had a negative influence on the physiological characteristics of plants. Thus, the hypothesis of action of the plant regulator as an elicitor hasn’t been proven in this study. However, the theme of this research is new, incipient and brought clarifying information, it is emphasizes the need to future research and development of works with varied and effective concentrations for metabolic and physiological reprogramming of plants.