Oxidant and antioxidant compounds, gas exchange and growth of young Schizolobium parahyba var. amazonicum plants under high boron and calcium concentrations

Abstract

Boron (B) and Calcium (Ca) unbalance in plants during early stages can generate oxidative stress and consequently to interfere negatively on growth and quality of seedlings. This study aims to evaluate the gas exchange and measure the biochemical responses, responding how high concentrations of B and Ca can affect the growth and quality of young Schizolobium parahyba plants. The experimental design used was completely randomised with four treatments [1 -25 µM B + 5 mM Ca (control); 2 -25 µM B + 50 mM Ca (Ca high); 3-250 µM B + 5 mM Ca (B high) and 4 -250 µM B + 50 mM Ca (B and Ca high)]. Negative impacts on gas exchange, photosynthetic pigments and total glutathione were obtained, besides increases in hydrogen peroxide and electrolyte leakage were verified in plants treated with B and Ca high, indicating oxidative stress. Thus, application 250 µM B combined with 50 mM Ca promoted disorders in plant metabolism, decreasing the growth and quality of young Schizolobium parahyba plants. Callegari, et al.: Boron and calcium in Schizolobium parahyba plants Emir. J. Food Agric • Vol 29 • Issue 12 • 2017 995 Fig 4. Ascorbate in leaf (A), ascorbate in root (B), glutathione total in leaf (C) and glutathione total in root (D) in young S. parahyba plants subjected to different of B and Ca supplies. Bars with different letters indicate significant differences from the Skott-Knott test (P<0.05). Bars represent the mean values and error bars represent the standard deviations from five repetition.