Shaw G, Leake J R, Baker A J M, Read D J
Department of Animal and Plant Sciences, The University of Sheffield, Sheffield S10 2TN, UK.
New Phytol. 1990 Jun;115(2):251-258. doi: 10.1111/j.1469-8137.1990.tb00450.x.
The role of the ericoid mycorrhizal endophyte Hymenoscyphus ericae (Read) Korf & Kernan in the regulation of iron uptake by ericaceous plants is investigated. Growth of the fungus is not inhibited in solution cultures containing a range (0-144 [ig ml ) of iron concentration ([Fe] ) typical of those obtained in extracts from heathland soil. Absorption of iron by the fungus occurs rapidly at low [Fe] but more slowly as [Fe] increases. Concentrations of iron in the mycelium ([Fe] ), reach 6000μg g dry weight. Mycorrhizal (M) roots of Vaccinium macrocarpon Ait. and Calluna vulgaris L. (Hull) showed a very high affinity for iron at low [Fe] , a feature not shown by non-mycorrhizal (NM) roots. The involvement of a hydroxamate siderophore in the absorption of Fe by M plants at low [Fe] is suggested. Concentrations of iron in shoots ([Fe] of NM plants of V. macrocarpon increase linearly with increasing [Fe] while those of M plants fall in the mid-range of [Fe] relative to initial and final values. Ratios of [Fe] to [Fe] are lower in M than in NM plants across the range of [Fe] examined. The extent of involvement of mycorrhizal infection in excluding the metal from shoots as [Fe] increases, is discussed, and the importance of the mechanisms of iron capture and storage in the root are assessed in terms of iron availability in natural heathlands.
研究了欧石楠类菌根内生真菌欧石楠 Hymenoscyphus ericae（里德）科夫和克南在调节欧石楠科植物铁吸收中的作用。在含有一系列（0 - 144μg/ml）典型的石南荒地土壤提取物中铁浓度（[Fe]）的溶液培养中，真菌的生长未受到抑制。真菌在低[Fe]时快速吸收铁，但随着[Fe]增加吸收速度减慢。菌丝体中的铁浓度（[Fe]）达到6000μg/g干重。大果越桔和普通石楠的菌根（M）根在低[Fe]时对铁表现出非常高的亲和力，而非菌根（NM）根则没有此特征。推测在低[Fe]时，一种异羟肟酸型铁载体参与了M植物对铁的吸收。大果越桔NM植物地上部的铁浓度（[Fe]）随[Fe]增加呈线性增加，而M植物的铁浓度在[Fe]的中间范围相对于初始值和最终值下降。在所研究的[Fe]范围内，M植物的[Fe]与[Fe]之比低于NM植物。讨论了随着[Fe]增加菌根感染在阻止金属进入地上部中的参与程度，并根据天然石南荒地中铁的有效性评估了根部铁捕获和储存机制的重要性。
