Silício e restrição hídrica na integridade do aparato fotossintético e crescimento inicial de Inga vera Willd

Abstract

The silicon (Si) applied leafy way can mitigate damage to the photosynthetic apparatus and increase the resilience of seedlings under water deficit. The objective of this study was to discuss the potential of silicon to mitigate the stressful effect and aid in physiological recovery of Inga Vera Willd during and after water restriction. Two water regimes were studied: control: daily irrigation and water restriction (RH): suspension of irrigation, until the plants presented symptoms of water deficit (SDH). The RH regimen was combined with three doses of Si: 0.84, 1.68 and 3.36 g of Si. The plants were kept under water deficit until they presented symptoms of water deficit, when the irrigation was resumed for 30 days, characterizing the recovery period (REC). Untreated plants with 3.36 g od Si had SDH at 7 days of RH, while with 0.84 and 1.68 g they tolerate 9 and 11 days of RH, respectively. There was a reduction in the photosynthetic rate, with values close to zero in the SDH period, in plants without and with 3.36 g of Si. Intermediate doses of Si, especially 0.84 g, mitigated the damage to the photosynthetic apparatus and water use, and favored physiological recovery. The beneficial effect of Si in the reaction centers occurred with 0.84 g, favoring the increase of photochemical efficiency in photosystem II in the REC. I.vera has physiological plasticity, because despite the initial growth being negatively affected by water restriction, there was recovery after the water supply resumed. Si application is a promising practice for contributing to the regulation of I.vera gas exchange during and after the stress period.