| Abstrakt: |
Silicon (Si) could contribute to the stability of photosystem II processes and gas exchange. Moreover, it can increase antioxidant enzyme activity, maintaining the growth of Eugenia myrcianthesNied. seedlings under water fluctuation, favoring seedling tolerance and recovery after stress suspension. We aimed to evaluate the effect of the foliar application of silicon on E. myrcianthesseedlings subjected to water fluctuation and the potential to recover photosynthetic and enzymatic metabolisms and seedling growth at the post-stress period. There were two water regimes: continuous irrigation (I), with 75% of the water retention capacity of the substrate, and water stress (S), with irrigation suspension followed by flooding. The water regimes were associated with different Si concentrations: 0, 2, and 4 mmol L−1. The seedlings were evaluated in five periods: time zero (T0), with initial evaluations and irrigation suspension; first photosynthesis close to zero under water deficit, 1st P0; first recovery, 1st REC; second photosynthesis close to zero under flooding, 2nd P0; second recovery, 2nd REC. Water fluctuation negatively affected the photosynthetic and enzymatic metabolism of E. myrcianthes. However, we observed 100% survival of the all seedlings, suggesting the physiological plasticity of the species. The application of 2 mmol L−1of Si on the seedlings helped them to tolerate the stressful effect of water fluctuation. Water stress decreased the development of E. myrcianthesseedlings, damaging the photochemical and biochemical metabolism of photosynthesis, increasing antioxidant enzyme activity, and reducing root growth and seedling quality. However, 2 mmol of Si mitigated water stress (deficit and flooding) effects, favoring seedling development and tolerance to water fluctuation. The species can adjust to these stressful conditions and it shows potential for survival and tolerance at this stage of development, recovering its metabolism and growth after stress. |
Full text from SpringerLink