Fisiologia, crescimento e anatomia de plantas de Capsicum chinense cultivada sob salinidade e aplicação de prolina

Abstract

The pout pepper (Capsicum chinense Jacq.) is a crop that plays a prominent role in the cultural, gastronomic and economic spheres in Brazil. However, salinity is a major problem that affects several areas of irrigated cultivation. In this way, technologies have been used as a way to mitigate salt stress, as is the case with the application of proline. In this context, the objective was to test the effects of exogenous application of proline on the physiology, growth and anatomy of pout pepper plants cultivated under saline stress. The work was divided into two chapters. For this, an experiment was carried out with a randomized block design in a 5 x 5 incomplete factorial scheme. The treatments were a combination of five salinity levels of irrigation water (0.50; 1.3; 3.25; 5.2 and 6.0 dS m-1) and five doses of proline (0.0; 2 .90; 10; 17.09 and 20 mM). In chapter I, the effect of exogenous proline on the growth and ecophysiology of pout pepper irrigated with saline water was studied. Irrigation with water of 0.5 dS m-1 provided greater growth of pepper plants. Plants irrigated with medium salinity (2.71 and 3.25 dS m-1), combined with the application of low doses of proline (0.0 and 5.5 mM), showed greater net photosynthesis, transpiration, intrinsic carboxylation efficiency, intrinsic efficiency of water use, chlorophyll a and b, electrolyte extravasation and relative water content. In chapter II, the vegetative organs of pepper were anatomically characterized. The structural characteristics of the vegetative organs of pout pepper were common to those of species from the Solanaceae family. Anatomical characteristics that help optimize light capture were identified, such as convex cells in the epidermis of the stem and leaf, and stomata were also observed located above the cuticle lining, a characteristic related to greater water loss by the plant.