Mitteilungen der Gesellschaft für Pflanzenbauwissenschaften Band 23

Mitt. Ges. Pflanzenbauwiss. 23: 151 (2011)
Manganese leaf tissue tolerance and sensitivity in rice
(Oryza sativa L.)
Martin Duschyk, Hendrik Führs and Walter J. Horst
Institute of Plant Nutrition, Gottfried Wilhelm Leibniz University-Hannover. E-Mail: duschyk@pflern.unihannover.de
Introduction
On acid soils of many tropical and subtropical regions Mn toxicity reduces yields of
crops (Foy, 1984). In subsistence agriculture liming is often not economic or
recommended. Great differences in Mn sensitivity were observed between different
species and cultivars, which could contribute to develop Mn-tolerant cultivars. Rice
(Oryza sativa) represents a plant species with generally high Mn leaf-tissue tolerance
compared to other cereals. The physiological and molecular mechanisms of Mn
tolerance in rice are not yet understood.
Material and Methods
In addition to necrosis and chlorosis primarily typical Mn toxicity symptoms in rice are
brown spots on old leaves which consist of oxidized Mn and oxidized phenols (Horst,
1988).Therefore, the area of brown spots was used as parameter for the screening
for Mn sensitivityof a Recombinant Inbred Line (RIL) population of 92 individuals.
Since preliminary studies substantiated that also in rice the apoplast is a key
compartment for Mn tolerance (Führs et al. 2010), apoplastic washing fluid (AWF)
was extracted from leaves and activities NADH-peroxidase, guaiacol-peroxidase, the
protein, phenol and Mn concentrations were measured.
Results and Discussion
The phenotyping for Mn toxicity symptoms of the RILs revealed great differences in
Mn tolerance among the population exceeding by far the differences between the
parents of the population. No correlation existed between Mn toxicity symptoms and
Mn bulk-leaf concentrations. Two tolerant and two sensitive RILs were selected from
this population for further in-depth studies. After prolonged and high Mn supply the
Mn-tolerant RILs showed lower activities of NADH- and guaiacol-POD and lower Mn
concentrations in the AWF although the bulk-leaf Mn concentrations did not differ.
References
Foy, C.D. 1984: Physiological effects of hydrogen, aluminium, and manganese toxicities in acid soils.
In: Adams, F. (ed.) Soils acidity and liming. Agron. Monograph 12 ASA-CSSSA, Madison, USA, pp.
57-97
Führs, H. et al. 2010: Physiological and proteomic characterization of manganese sensitivity and
tolerance in rice (Oryza sativa) in comparison with barley (Hordeum vulgare). Annals of Botany
105:1129-1140.
Horst, W.J. 1988: The physiology of Mn toxicity. In: Graham, R.D., Hannam, R.J., Uren, N.C. (eds.)
Manganese in soils and plants. Kluwer, Dodrecht/Boston/London. pp 175-188.