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Aluminum toxicity and water deficit effects on leaf photosynthesis and stomatal conductance, growth traits, proline, organic acids, and mineral nutrients in sorghum
Abstract
Sorghum (Sorghum bicolor L. Moench) grown in acid soils (high Al) shows growth and root physiology symptoms similar to plants grown under drought. Since compatibility exists between Al tolerance and drought resistance, the effects of Aluminum (Al) toxicity and water deficit (WD) stresses on net photosynthesis, leaf stomatal conductance, growth traits, proline, organic acids, and mineral nutrient concentrations in shoots and roots need to be determined. SC283 (drought- and Al-tolerant) and 'Redlan' (drought- and Al-sensitive) sorghum genotypes were grown under Al and WD individually, and Al + WD combined in nutrient solutions. Photosynthesis and stomatal conductance decreased as Al and WD in nutrient solution increased. Additive Al + WD stresses decreased photosynthesis and stomatal conductance more than Al or WD separately. Increased Al and WD stresses decreased shoot, root and total dry matter yields (DMY). Aluminum increased shoot/root DMY ratios, and WD increased shoot/root DMY ratios in some experiments and decreased them in others. Leaf areas and root lengths decreased similar to other DMY as Al level and WD increased. Increased Al did not affect proline in shoots and roots. Water deficit treatments increased proline, and had greater effect than Al. Combinations of 200 or 400 $\mu$M Al levels with $-$0.09 or $-$0.13 MPa WD resulted in higher proline in shoots and roots than Al or WD separately. Shoots had higher proline than roots. Shoot organic acids were not affected when grown with Al. t-Aconitic acid in roots was less in plants grown with 200 $\mu$M Al than in plants grown at control treatment. Control compared to WD treatments increased shoot fumaric and oxalic acids. Water deficit affected shoot and root organic acids more than Al. Adding Al to nutrient solutions increased shoot and root P and Al and decreased shoot S and Fe and shoot and root Mg, Ca, Mn, and Zn concentrations. Water deficit increased shoot and root P, Mg, and Zn, and decreased shoot and root S, K, Ca, Mn, and B and root Fe.
Subject Area
Agronomy
Recommended Citation
Zaifnejad, Mojtaba, "Aluminum toxicity and water deficit effects on leaf photosynthesis and stomatal conductance, growth traits, proline, organic acids, and mineral nutrients in sorghum" (1993). ETD collection for University of Nebraska-Lincoln. AAI9412213.
https://digitalcommons.unl.edu/dissertations/AAI9412213