Mecanismos fisiológicos induzidos pelo iodato de potássio via solo na mitigação de estresse por déficit hídrico em cafeeiros (Coffea Arabica L.)

Abstract

Water deficit directly impacts plant growth and development, promoting physiological disturbances that trigger oxidative stress. As an alternative to this problem, the exogenous application of a sort of molecule that can minimize these damages and reduce productivity losses. Applying iodine (I) has shown considerable results in improving photosynthetic efficiency and stimulating the antioxidant system in stressed plants. Nevertheless, there are few results for mitigating the water deficit in coffee plants. Thus, coffee plants were grown in 10-liter pots arranged wholly randomized. Four doses of potassium iodate (KIO3) were tested: 0.0, 2.5, 5.0, and 10.0 mg dm-3

of soil, then the plants were subjected to water deficit and compared to treatments with no KIO3 and water deficit (Control). In our stydy we show the influence of water deficit on biomass decline and relative growth of the coffee plant. However, the application of 2.5 mg dm-3

of KIO3 attenuated the water deficit symptoms, increasing photosynthetic efficiency, relative water content, water deficit tolerance index, content of photosynthetic pigments, and compatible osmolytes. In addition, we observed the stimulation of the antioxidant enzymatic system, causing a decline in the degradation of cell membranes. Doses of 5.0 and 10.0 mg dm-3

of KIO3 induced greater activation of the antioxidant system without influencing plant development, compared to plants exposed to water deficit, implying a possible toxicity effect due to excess KIO3. Therefore, it was observed that the application of 2.5 mg dm-3 KIO3 via the soil can modulate metabolic and biochemical processes, allowing an improvement in the growth and development of coffee plants subjected to water deficit, suggesting that it could serve as a viable strategy for managing plants under drought conditions.