Fisiologia e produção de pinheira cultivada sob turnos de rega e aplicação de prolina.

Abstract

The prolonged periods of drought have hampered the cultivation of fruit trees in the semi- arid region of Paraíba, making their growth and development unfeasible, bringing a series of losses to producers, making it necessary to adopt irrigation management strategies, and the search for alternatives that may mitigate the effects of stress on plants. Thus, the objective of this work was to evaluate the effects of foliar application of proline as a mitigator of water stress on the physiology and production of sugar apple in the semi-arid region of Paraíba. The research was carried out under field conditions in São Domingos, PB, using a randomized block design in a 4 × 2 factorial scheme, whose treatments resulted from the combination of four irrigation shifts (1, 4, 8 and 12 days) and two concentrations of proline (0 and 10 mM), with four replications, whose plot consisted of four useful plants, making a total of 128 experimental units. The increase in watering shifts reduced gas exchange in sugar apple plants, 298 days after transplanting. The application of proline at a concentration of 10 mM increased electrolyte leakage in the leaf blade, stomatal conductance, chlorophyll a, totals and carotenoids, and decreased the internal concentration of CO2 in sugar apple plants. The exogenous application of proline at a concentration of 10 mM stimulated the biosynthesis of chlorophyll b, and the increase in the fresh mass of fruits in plants cultivated under a 12-day irrigation shift.