tailieunhanh - SOYBEAN MOLECULAR ASPECTS OF BREEDING_2

The book Soybean: Molecular Aspects of Breeding focuses on recent progress in our understanding of the genetics and molecular biology of soybean and provides a broad review of the subject, from genome diversity to transformation and integration of desired genes using current technologies. This book is divided into four parts (Molecular Biology and Biotechnology, Breeding for Abiotic Stress, Breeding for Biotic Stress, Recent Technology) and contains 22 chapters. | 11 Genotypic Influence on the Absorption Use and Toxicity of Manganese by Soybean Andre Rodrigues dos Reis1 and Jose Lavres Junior2 Department of Civil and Environmental Engineering Waseda University. 169-8555 Shinjuku-ku Okubo 3-4-1 Tokyo 2Laboratory of Plant Nutrition University of Sao Paulo. - 13400-970 - Piracicaba SP 1Japan 2Brazil 1. Introduction Plant species and genotypes within species can differ widely in their tolerance to excess manganese Mn Foy et al. 1988 or susceptibility to its deficiency Graham 1988 in the soil or other substrate in which they grow. Often these differences are hereditary Broadley White 2005 Pittman 2005 . Although manganese Mn toxicity can be a common problem in tropical regions with acid soils Mn deficiency in soybeans Glycine max L. grown in Brazilian Cerrado savanna has been recognized as a nutritional disorder frequently related to excessive liming Tanaka et al. 1992 . However the variations in the concentrations of Mn in plants have been attributed either to genetic factors or to soil fertility conditions Fageria 2001 . Plant species and genotypes within the same species can differ widely in the tolerance to high Mn Foy et al. 1988 as well as in susceptibility to the deficiency when grown under conditions of low Mn availability Graham 1988 . The mechanisms of tolerance to excess Mn have been associated with oxidation of the Mn in the roots restricted absorption by the roots and translocation of the excess Mn to the leaves as well as uniform distribution in the tissues greater internal tolerance and interaction with other elements mainly K Ca Mg Fe and Si and defense mechanisms against oxygen reactive species such as activation of enzymes like ascorbate peroxidase catalase Mn-superoxide dismutase and glutathione peroxidase Demirevska-Kepova et al. 2004 Morita et al. 2006 . On the other hand better internal utilization or lower requirement greater redistribution of Mn increased rate of absorption exudation of organic .