Changes in root cell wall chemistry induced by manganese exposure with two tobacco genotypes

Document Type

Article

Publication Date

7-18-2003

Abstract

Induced effects by manganese (Mn) uptake on root cell walls of two tobacco (Nicotiana tabacum L.) genotypes KY 14 (Mn sensitive) and T.I. 1112 (Mn tolerant) were evaluated. The tobacco genotypes were grown in half-strength Hoagland solutions containing 0 (deficient), 46 (non-toxic), and 300 μM (toxic) Mn. Root cell walls were isolated and characterized for total polysaccharides, proteins, and individual sugars and amino acids. For both genotypes, the largest and significant difference (P ≤ 0.01) in cell wall polysaccharides and proteins were between Mn levels of 0 and 46 μM. Either deficient or toxic levels of Mn exposure decreased uronic acid, a component of cell wall pectins although the decrease was smaller in T.I. 1112 than in KY 14. Beside uronic acid, significant changes in arabinose, galactose, and rhamnose contents were also observed in cell wall pectins. In addition, toxic level of Mn exposure greatly elevated serine in T.I. 1112 whereas the Mn deficient condition generally reduced serine but increased proline in both genotypes. Serine and hydroxyl-proline are major amino acid components of extension, a major cell wall structural protein. The results suggest that Mn deficiency and toxicity may affect both metal uptake and mechanical characteristics of tobacco root cell walls. Manganese-induced changes in root cell wall chemistry appear to differ from the effects of metal stresses of non-essential elements such as aluminum (Al) and sodium (Na).

Publication Source (Journal or Book title)

Journal of Plant Nutrition

First Page

1527

Last Page

1540

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