Impact of drought and flooding stresses on Gabiroba plants

Abstract

The aim of this study was to evaluate the tolerance of Gabiroba plants (Campomanesia spp) to drought and flooding stresses for 0, 3, 6, 9, 12, 15, and 18 days. The contents of dry matter, water, nitrate reductase activity, total soluble sugars, sucrose, starch, insoluble and soluble protein, and soluble amino acid in leaves and roots were periodically determined. Drought and flooding induced a significant reduction in the contents of water and dry matter of leaves and roots. The contents of total soluble sugars, sucrose, and starch suggest a reduction in the photosynthetic rate, remobilization of starch reserves, and transport blocking in the phloem. Drought stress leads to decreased protein synthesis and accumulation of amino acids. The higher concentration of insoluble proteins in the leaves and roots of plants under flooding is a consequence of the synthesis of new polypeptides. For the leaves, the lowest and highest contents of amino acids were found under drought and flooding stresses, respectively; whereas for the roots, the lowest rates were found under drought stress. Gabiroba plants are tolerant to drought stress and remobilize soluble carbohydrates from the shoots to the roots.