Effects of aluminum on mycorrhizal and non-mycorrhizal broomsedge.
NING, J.* and J.R.CUMMING
West Virginia University, Morgantown, WV 26506 USA 1
Elevated aluminum (Al) toxicity is the primary factor limiting plant growth on acidic soils. Toxic Al may interfere with the acquisition and metabolism of mineral nutrients, disrupt cell membranes, and alter enzyme activities. Ninety-five percent of higher plants form symbiotic associations with mycorrhizal fungi. Fungal hyphae penetrate root tissues and transfer mineral nutrients into roots for exchange of carbohydrates from the host. Many studies demonstrated that mycorrhizal colonization aids plant growth and improves plant survival over adverse edaphic soils. The present study examined differential responses of mycorrhizal and non-mycorrhizal broomsedge plants to toxic levels of Al. Mycorrhizal colonization significantly enhanced plant growth and there were significant interactions between mycorrhizal and Al treatments for tissue dry weights reflecting mycorrhizal amelioration of Al toxicity. Aluminum concentrations of tissues increased with increasing Al application. Colonization of mycorrhizal fungi significantly reduced tissue Al concentrations early in the experiment. Later, there was no significant difference in tissue Al concentrations between mycorrhizal and non-mycorrhizal plants. Shoot P concentrations were significantly enhanced by mycorrhizal colonization early in the experiment. Aluminum application had no significant effect on root P concentrations. Mycorrhizal colonization significantly ameliorated broomsedge plant growth under toxic Al conditions. At the early stage of broomsedge growth, mycorrhizal fungi probably assisted the plant to overcome toxic Al by enhancement of Pi uptake.
Keywords: Aluminum toxicity, broomsedge, endomycorrhizae, phosphorus
This abstract is being presented at: 3:30 PM in session: