Distribution and Amelioration of Manganese Toxic Soils

“…Manganese (Mn) excess represents an important factor limiting growth and crop yields particularly on acid and insufficiently drained soils with low redox potential (Foy, 1984;Schlichting and Sparrow, 1988). The oxidation of Mn II and phenolic compounds catalyzed by peroxidase (apoplastic peroxidase [POD]) in the leaf apoplast is considered as a key reaction leading to Mn toxicity symptoms and finally leaf injury in cowpea (Vigna unguiculata L. Walp.…”

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confidence: 99%

The Role of Hydrogen Peroxide-Producing and Hydrogen Peroxide-Consuming Peroxidases in the Leaf Apoplast of Cowpea in Manganese Tolerance

et al. 2006

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The apoplast is considered the leaf compartment decisive for manganese (Mn) toxicity and tolerance in cowpea (Vigna unguiculata). Particularly apoplastic peroxidases (PODs) were proposed to be key enzymes in Mn toxicity-induced processes. The presented work focuses on the characterization of the role of hydrogen peroxide (H 2 O 2 )-producing (NADH peroxidase) and H 2 O 2 -consuming peroxidase (guaiacol POD) in the apoplastic washing fluid (AWF) of leaves for early stages of Mn toxicity and genotypic differences in Mn tolerance of cowpea. Leaf AWF of the Mn-sensitive cultivar (cv) TVu 91 but not of the Mntolerant cv 1987 showed an increase of guaiacol-POD and NADH-peroxidase activities at elevated AWF Mn concentrations. two-dimensional resolutions of AWF proteins revealed that cv TVu 91 expressed more and additional proteins at high Mn treatment, whereas Mn-tolerant cv TVu 1987 remained nearly unaffected. In both cultivars, NADH-peroxidase activity and accompanied H 2 O 2 formation rate in vitro were significantly affected by Mn 21 , p-coumaric acid, and metabolites occurring in the AWF. The total phenol concentration in the AWF was indicative of advanced stages of Mn toxicity but was rather unrelated to early stages of Mn toxicity and genotypic differences in Mn tolerance. The NADH oxidation by AWF PODs was significantly delayed or enhanced in the presence of the protein-free AWF from cv TVu 1987 or cv TVu 91, respectively. High-performance liquid chromatography analysis of AWF indicates the presence of phenols in cv TVu 1987 not observed in cv TVu 91. We conclude from our studies that the H 2 O 2 -producing NADH peroxidase and its modulation by stimulating or inhibiting phenolic compounds in the leaf apoplast play a major role for Mn toxicity and Mn tolerance in cowpea.

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“…Selection was therefore carried out at high soil water content either in the field or in sealed tanks containing Phytophthora-infested soil (Beard and Kawaguchi 1978). Such conditions may have produced a poor soil aeration (waterlogging) which would have resulted in increased concentrations of Mn 2+ in the soil solution (Schlichting and Sparrow, 1988), particularly if the soil contained sufficient quantities of reducible Mn. Cimmaron was also selected for Phytophthora resistance, and has been noted as a more waterloggingtolerant lucerne cultivar in South Australia (I Kahne, pers comm).…”

Section: Discussionmentioning

confidence: 99%

Tolerance to manganese toxicity among cultivars of lucerne (Medicago sativa L.)

1992

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Two sand culture experiments were carried out to identify commercial cultivars of lucerne or alfalfa (Medicago sativa L.) which contain elite, Mn-tolerant plants for use in a selection programme to increase the acid-soil tolerance of this perennial legume. Differences in Mn tolerance, both within and between cultivars, were observed when a range of cultivars were exposed to regular waterings with dilute nutrient solution containing 20 or 25 mg Mn L 1. Under these moderately toxic regimes, the winter dormant cultivars Cimmaron and WL 318 were found to contain elite plants that had greater dry matter yields than their mean cultivar yield under non-toxic Mn conditions. Cultivars which contained elite, Mn-tolerant plants could not be identified by phenotypic characteristics such as their height or their toxicity symptom score, nor by their winter dormancy class. Possible reasons for the occurrence of elite plants in these cultivars are discussed. The elite, high yielding Mn-tolerant plants could not be identified from the other plants within their cultivar population by their Mn toxicity symptoms nor by their height.

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Distribution and Amelioration of Manganese Toxic Soils

Cited by 26 publications

References 77 publications

Physiological and proteomic characterization of manganese sensitivity and tolerance in rice (Oryza sativa) in comparison with barley (Hordeum vulgare)

Physiological and proteomic characterization of manganese sensitivity and tolerance in rice (Oryza sativa) in comparison with barley (Hordeum vulgare)

The Role of Hydrogen Peroxide-Producing and Hydrogen Peroxide-Consuming Peroxidases in the Leaf Apoplast of Cowpea in Manganese Tolerance

Tolerance to manganese toxicity among cultivars of lucerne (Medicago sativa L.)

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