Biochemical compounds and enzymatic systems related to tolerance to water deficit of maize seedlings

Abstract

The use of vigorous seeds in drought situations, it may be a strategy to ensure tolerance to drought for better development of the seedlings. It was evaluated whether maize (Zea mays L.) plants from seeds with high vigor possess greater tolerance to water deficit than low vigor seeds and to identify which morphological parameters, biochemical compounds and enzymatic systems are more important for this tolerance. Two maize hybrids with contrasting seed vigor were used: HT1 (high vigor) and HT2 (low vigor). Two pre-established moisture treatments were used one without stress (control, 80% maximum gravimetric moisture) and the other with water restriction (50%). After 20 days, the size and volume of the roots were analyzed and the contents of total soluble proteins, proline and hydrogen peroxide and the activity of antioxidant enzymes, such as superoxide dismutase, catalase and ascorbate peroxidase, were determined for leaf tissue. The HT1 hybrid (high vigor) demonstrated a greater capacity to combat oxidative stress with the accumulation of proline and increased activity of antioxidant enzymes, which may be indicative of tolerance to water deficit. The variables that most contributed to the tolerance to water deficit in HT1 were increased activity of the enzymes catalase and ascorbate peroxidase, and a reduction in hydrogen peroxide content.