Respostas fisiológicas de dois híbridos de palma de óleo (Elaeis guineensis Jacq.) à salinidade.

Abstract

This study evaluated the changes in nitrogen metabolism in two oil palm hybrids (BRS Manicoré and Tenera) subjected to saline stress. The experiment was conducted in a greenhouse, with plants exposed to increasing concentrations of NaCl (up to 400 mmol L⁻¹). The plant water status (predawn and morning leaf water potential and relative water content), substrate attributes (pH, electrical conductivity), and nitrogenous and osmoregulatory compounds (nitrate, ammonium, total amino acids, proline, glycine betaine, soluble proteins, carbohydrates) were analyzed. The results demonstrated that saline stress significantly reduced the predawn and morning leaf water potential in the salinized plants of both hybrids, but without a reduction in the relative water content, whose general average was around 87% considering all treatments, indicating osmotic adjustment. In relation to the control, both hybrids accumulated two times more total amino acids and proline under salinity. The Tenera hybrid stood out for its greater accumulation of nitrate (+20%) and glycine betaine (+22%), while the Manicoré hybrid elevated total soluble proteins (+125%) and sucrose (+7%). It is concluded that the hybrids employed distinct metabolic strategies: Tenera prioritizes organic osmolytes (proline, glycine betaine) for rapid osmotic adjustment, and Manicoré invests in protein stability and carbohydrates for stress tolerance. These genotypic differences provide support for the selection of salinity-tolerant hybrids in oil palm.