Rhizomorphs in mycorrhizal fungi maintain plant hydration by transporting fluid between the root systems of neighboring plants


"Plant roots may be linked by shared or common mycorrhizal networks (CMNs) that constitute pathways for the transfer of resources among plants…Our results suggest that the movement of water by CMNs is potentially important to plant survival during drought, and that the functional ecophysiological traits of individual mycorrhizal fungi may be a component of this mechanism." (Egerton-Warburton et al. 2007:1473)

"For example, the dominant taxa within the mesocosms, i.e. Boletus, Cortinarius, and Pisolithus, produce hydrophobic mantles and well-differentiated rhizomorphs, two traits considered typical of drought-resistant EM [ectomycorrhizal] (Agerer, 2001). These well-differentiated rhizomorphs transport and hold significant amounts of water in the large diameter vascular vessels (Duddridge et al., 1980; Brownlee et al., 1983; Agerer, 2001, see also Fig. 2). Lactarius produces smooth, undifferentiated rhizomorphs, whereas Cenococcum mycorrhizae form envelopes of external hyphae rather than rhizomorphs (Agerer, 2001) that promote more localized distributions of water (Fig. 4). Further, hyphal anastamosis by AMF may create large interconnected networks with low resistance to solute flow (Giovanetti et al., 2004)." (Egerton-Warburton et al. 2007:1482)

Journal article
Common mycorrhizal networks provide a potential pathway for the transfer of hydraulically lifted water between plantsJournal of Experimental BotanyOctober 3, 2007
L. M. Egerton-Warburton, J. I. Querejeta, M. F. Allen