Genotypical differences among graminaceous species in release of phytosiderophores and uptake of iron phytosiderophores
- 233 Downloads
Graminaceous species can enhance iron (Fe) acquisition from sparingly soluble inorganic Fe(III) compounds by release of phytosiderophores (PS) which mobilize Fe(III) by chelation. In most graminaceous species Fe deficiency increases the rate of PS release from roots by a factor of 10–20, but in some species, for example sorghum, this increase is much less. The chemical nature of PS can differ between species and even cultivars.
The various PS are similarly effective as the microbial siderophore Desferal (ferrioxamine B methane sulfonate) in mobilizing Fe(III) from a calcareous soil. Under the same conditions the synthetic chelator DTPA (diaethylenetriamine pentaacetic acid) is ineffective.
The rate of Fe(III)PS uptake by roots of graminaceous species increases by a factor of about 5 under Fe deficiency. In contrast, uptake of Fe from both synthetic and microbial Fe(III) chelates is much lower and not affected by the Fe nutritional status of the plants. This indicates that in graminaceous species under Fe deficiency a specific uptake system for FePS is activated. In contrast, the specific uptake system for FePS is absent in dicots. In a given graminaceous species the uptake rates of the various FePS are similar, but vary between species by a factor of upto 3. In sorghum, despite the low rate of PS release, the rate of FePS uptake is particularly high.
The results indicate that release of PS and subsequent uptake of FePS are under different genetic control. The high susceptibility of sorghum to Fe deficiency (‘lime-chlorosis’) is most probably caused by low rates of PS release in the early seedling stage. Therefore in sorghum, and presumably other graminaceous species also, an increase in resistance to ‘lime chlorosis’ could be best achieved by breeding for cultivars with high rates of PS release. In corresponding screening procedures attention should be paid to the effects of iron nutritional status and daytime on PS release as well as on rapid microbial degradation of PS.
Key wordsbarley chlorosis resistance cucumber genotypical differences grasses iron mobilization iron uptake maize microorganisms oat phytosiderophores rice root exudates root growth rye sorghum wheat
Unable to display preview. Download preview PDF.
- Awad, F, Römheld, V and Marschner, H 1988 Mobilization of ferric iron from a calcareous soil by plant-borne chelators (phytosiderophores). J. Plant Nutr. 11, 701–713.Google Scholar
- Clark, R B, Römheld, V and Marschner, H 1988 Iron uptake and phytosiderophore release by roots of sorthum genotypes. J. Plant Nutr. 11, 663–676.Google Scholar
- Crowley, D E, Reid, C P P and Szaniszlo, P J 1987 Microbial siderophores as iron sources for plants. In Iron Transport in Microbes, Plants and Animals. Eds. G Winkelmann, D Van der Helm and J B Neilands. pp 375–386. VCH Verlagsgesellschaft, Weinheim, FRG.Google Scholar
- Kannan, S 1980 Differences in iron stress response and iron uptake in some sorghum varieties. J. Plant Nutr. 2, 347–358.Google Scholar
- Kawai, S, Sato, Y and Takagi, S 1987 Separation and determination of mugineic acid and its analogues by high-performance liquid chromatography. J. Chromatography 391, 325–327.Google Scholar
- Kawai, S, Itoh, K and Takagi, S 1988 Studies on phytosiderophores: Biosynthesis of mugineic acid and 2′ deoxymugineic acid in Hordeum vulgare L. var. Minori mugi. Tetrahedron Letters 29, 1053–1056.Google Scholar
- Kissel M 1987 Eisenmangel-induzierte Abgabe von Phytosiderophoren aus Gerstenwurzeln als effizienter Mechanismus zur Eisenmobilisierung. Ph. thesis University Hohenheim, Stuttgart, FRG.Google Scholar
- Marcar, N E and Graham, R D 1986 Effect of seed manganese content on the growth of wheat (Triticum aestivum) under manganese deficiency. Plant and Soil 96, 165–173.Google Scholar
- Marschner, H, Römheld, V and Kissel, M 1986 Different strategies in higher plants in mobilization and uptake of iron. J. Plant Nutr. 9, 695–713.Google Scholar
- Marschner, H, Römheld, V and Kissel, M 1987 Localization of phytosiderophore release and iron uptake along intact barley roots. Physiol. Plant. 71, 157–162.Google Scholar
- McDaniel, M E and Brown, J C 1982 Differential iron chlorosis of oat cultivars: A review. J. Plant Nutr. 5, 545–552.Google Scholar
- McKenzie, D B, Hossner, L R and Newton, R J 1986 The influence of NH4 +-N vs. NO3 --N nutrition on root reductant release by Fe stressed sorghum. J. Plant Nutr. 9, 1289–1301.Google Scholar
- Mengel, K and Geurtzen, G 1986 Iron chlorosis on calcareous soils: Alkaline nutritional condition as the cause for the chlorosis. J. Plant Nutr. 9, 161–173.Google Scholar
- Nishizawa, N and Mori, S 1987 The particular vesicle appearing in the barley root cells and its relation to mugineeic acid secretion. J. Plant Nutr. 10, 1013–1020.Google Scholar
- Römheld, V 1987 Existence of two different strategies for the acquisition of iron in higher plants. In Iron Transport in Microbes, Plants and Animals. Eds. G Winkelmann, D van derHelm and J B Neilands. pp 353–374. VCH Verlagsgesellschaft, Weinheim, FRG.Google Scholar
- Takagi, S 1976 Naturally occurring iron-chelating compounds in oat- and rice-root washings. Soil Sci. Plant Nutr. 22, 423–433.Google Scholar
- Takagi, S, Nomoto, K and Takemoto, T 1984 Physiological aspect of mugineic acid, a possible phytosiderophore of graminaceous plants. J. Plant Nutr. 7, 469–477.Google Scholar
- Takagi, S, Kamei, S and Ming-Ho, Yu 1988 Efficiency of iron extraction from soil by mugineic acid family phytosiderophores. J. Plant Nutr. 11, 643–651.Google Scholar
- Treeby, M, Marschner, H and Römheld, V 1989 Mobilization of iron and other micronutrient cations from a calcareous soil by plant-borne, microbial and synthetic metal chelators. Plant and Soil 114, 217–226.Google Scholar
- Vose, P B 1982 Iron nutrition in plants: A world overview. J. Plant Nutr. 5, 233–249.Google Scholar