Arbuscular mycorrhizal fungi and nitrogen uptake
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MI NI-R EVIE W
Arbuscular mycorrhizal fungi and nitrogen uptake Mohammad Miransari
Received: 3 August 2010 / Revised: 19 November 2010 / Accepted: 22 November 2010 / Published online: 7 December 2010 © Springer-Verlag 2010
Abstract Nitrogen (N) is among the most important macro-nutrients signiWcantly aVecting plant growth and yield production. Accordingly, N must be supplied adequately so that optimum amounts of yield are resulted. There are diVerent ways of supplying N to the plant including the use of chemical and biological fertilization. The chemical properties of N make it very mobile, especially under humid conditions. Hence, N must not be overfertilized with respect to the economical and environmental points of view. N Biological fertilization includes the use of plant growth-promoting rhizobacteria (PGPR) including the N-Wxing bacteria, rhizobium. There are also arbuscular mycorrhizal (AM) fungi in the soil, which are symbiotic to most terrestrial plants enhancing plant growth and yield production through increasing the uptake of water and nutrients by the host plant. Numerous experiments have indicated the important role of AM fungi in enhancing P uptake by plant. However, it is yet a matter of debate that how AM fungi may aVect soil N dynamic and hence plant N uptake. Some of the most important and recent aspects regarding such eVects by AM fungi are highlighted, which can be of signiWcance to health and productivity of the ecosystem. Keywords AM fungi · Soil N dynamic · Plant N uptake · Tripartite symbiosis · Chemical and biological fertilization
Communicated by Erko Stackebrandt. M. Miransari (&) Department of Soil Science, College of Agricultural Sciences, Shahed University, Tehran Qom Highway, 18151-159, Tehran, Iran e-mail: [email protected]; [email protected]
Introduction Plant require a range of at least 16 macro- and micro-nutrients for their growth and yield production (Marschner 1995). Among such nutrients nitrogen (N) is of particular signiWcance because it is necessary for many diVerent plant functioning as it is incorporated in the structure of some important macro- and micro-organic compounds in the plant such as chlorophyll and proteins and amino acids (Marschner 1995). N is a mobile element in the soil and hence under humid conditions is subjected to leaching indicating the importance of appropriate N fertilization under such conditions. On the other hand, under arid and semi arid conditions, water deWciency may limit the use of inorganic N by plant. There are diVerent ways of supplying N to the plant including the use of chemical and biological fertilization. In the case of chemical fertilization, proper amounts of N must be supplied with respect to the economical and environmental aspects regarding N compounds (Miransari and Mackenzie 2010a, b, c). Biological fertilization can be performed by using soil microbes such as plant growth promoting rhizobacteria (PGPR) including the N-Wxing bacteria, rhizobium (Arzanesh et al. 2010; Zabihi et al. 2010; Miransari 2010a, b, c, d). In
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