Symbiotic Fungi: Principles and Practice (Soil Biology)

Chapter 17
15 N Enrichment Methods to Quantify Two-Way
Nitrogen Transfer Between Plants Linked
by Mychorrhizal Networks
X.H. He, C. Critchley, K. Nara, D. Southworth, and C.S. Bledsoe
17.1 Introduction
Nitrogen (N) movement or transfer from one plant (donor) to another (receiver) is
of fundamental importance in N2-fixing plant-based agricultural and natural ecosystems
(Stern 1993; Chalk 1998; Graham and Vance 2003; Forrester et al. 2006).
Nitrogen transfer is relevant to global concerns about N excess and N limitation in
terrestrial ecosystems (Vitousek et al. 1997; Moffat 1998; Sanchez 2002; Nosengo
2003). Numerous studies over the past three decades have demonstrated that plantto-plant
N transfer from the donor to the receiver is not restricted to mass flow and
diffusion through soil pathways, and can take place directly through mychorrhizal
hyphae in common mychorrhizal networks (CMNs) that interconnect roots. Such
mycorrhizal-mediated N movement between plants could have practical implications
for plant performance, especially in N-limited habitats (Sprent 2005; Forrester
et al. 2006; Nara 2006). However, recapture of decomposed and exuded plant and
fungal materials by the receiver may occur simultaneously in the soil.
X.H. He (*)
School of Plant Biology, University of Western Australia, Crawley, WA 6009, Australia
e-mail: xinhua@cyllene.uwa.edu.au, xinhua5658@hotmail.com
C. Critchley
School of Integrative Biology, University of Queensland, Brisbane, QLD 4072, Australia
K. Nara
Asian Natural Environmental Science Center, University of Tokyo, NishiTokyo, Tokyo 188-0002,
Japan
D. Southworth
Department of Biology, Southern Oregon University, Ashland, OR 97520, USA
C.S. Bledsoe
Department of Land, Air and Water Resources, University of California, Davis, CA 95616, USA
A. Varma and A.C. Kharkwal (eds.), Symbiotic Fungi, Soil Biology 18, 285
DOI: 10.1007/978‐3‐540‐95894‐9_17, # Springer‐Verlag Berlin Heidelberg 2009