Condicionamento de sementes de espécies florestais nativas: respostas fisiológicas e bioquímicas

Abstract

The recovery of degraded areas depends on the use of seeds of high physiological quality to ensure the proper establishment of seedlings. Physiological conditioning has proven to be a promising strategy for improving germination and vigor. This study evaluated the effects of physiological conditioning with different signaling molecules, such as sodium nitroprusside, gibberellic acid, potassium nitrate, and aqueous smoke extract, on the physiological and biochemical aspects of seeds from four forest species. Seed conditioning increased the germination rate, germination speed, and uniformity of seeds from the four species studied. The same was observed in the seedbeds, which presented a greater emergence rate and more uniform growth than did the control. The conditioned seeds presented a reduction in hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) levels, indicating decreased oxidative stress. An increase in the activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) was observed, reinforcing the ability to reduce damage caused by reactive oxygen species. The evaluation of storage after conditioning revealed that although physiological conditioning improved germination and seedling vigor, there was a reduction in seed longevity, increasing susceptibility to deterioration over time. These results reinforce the importance of physiological conditioning to improve seed performance and the need to consider viability after storage.