Evaluation of biochemical component determinants for superior seedling performance in high-vigor maize seeds under accelerated aging stress

ABSTRACT

Under stressful conditions, the use of high-vigor seeds is a relevant alternative to reduce losses, as they can germinate in a wide range of environmental conditions. However, it is necessary to understand the biochemical strategies adopted by high-vigor seeds to achieve better performance during periods of stress. Thus, the objectives of this research were to evaluate the tolerance of maize seeds of contrasting vigor subjected to different levels of stress due to accelerated aging and to verify whether differences in antioxidant metabolism and starch reduction explain the differences between vigor levels. The experiment was conducted with a high-vigor seed lot and a low-vigor seed lot, in a completely randomized design. The lots were subjected to 0, 24, 48, 60 and 72 hours of accelerated aging (45°C and 100% relative humidity), and after that the tests were carried out. The variables analyzed were the percentage of normal (first and second count) and abnormal seedlings, dead seeds, vigor index, electrical conductivity, total soluble sugars in the leachate, alpha-amylase activity, soluble sugar content, catalase activity, peroxide hydrogen, lipid peroxidation, proline, and carotenoid content. High-vigor seeds better tolerate stress conditions caused by high temperature and humidity. The higher content of total soluble sugars and alpha-amylase activity may explain the better performance of high-vigor seeds.

Key words
antioxidant metabolism; seed physiology; sugar metabolism; Zea mays