Germination of Seeds of Melanoxylon brauna Schott. under Heat Stress: Production of Reactive Oxygen Species and Antioxidant Activity

In this article, the authors aimed to analyze the physiological and biochemical alterations in Melanoxylon brauna seeds subjected to heat stress. For this, seed germination, electric conductivity (EC), the production of reactive oxygen species (ROS), and the activity of antioxidant enzymes were assessed. Seeds were incubated at constant temperatures of 25, 35, and 45 ◦C. Independent samples were first incubated at 35 and 45 ◦C and then transferred to 25 ◦C after the intervals of 24, 48, 72, and 96 h. To evaluate EC, seeds were soaked for 0, 24, 48, and 72 h, at 25, 35, and 45 ◦C and then transferred to Erlenmeyer flasks containing 75 mL of deionized water at 25 ◦C, for 24 h. ROS production and enzyme activity were assessed every 24 h in seeds soaked at the aforementioned temperatures. Germination did not occur at 45 ◦C. Seeds soaked at 35 ◦C for 72 h and then transferred to 25 ◦C showed higher percentages of germination and a higher germination speed. Seed soaking at 45 ◦C increased peroxide production, which compromised the antioxidant enzyme system due to a reduction in the activity of enzymes APX, POX, and CAT, thus ultimately also compromising the cell membrane system.

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Author(s): Marcone Moreira Santos, Eduardo Euclydes de Lima e Borges, Glauciana da Mata Ataíde, Genaina Aparecida de Souza

Publication: Forests - 2019