Financial support was provided by the National Science Foundation through grants DEB-0087263 and 9211768.
Loblolly pine, Trees -- Nutrition, Trees -- Effect of minerals on, Plant-soil relationships, Forest ecology
Most measurements of nutrient uptake use either hydroponic systems or soil-grown roots that have been disturbed by excavation. The first objective of this study was to test how root excavation affects nitrate uptake. Rates of NO3− uptake by mycorrhizal loblolly pine (Pinus taeda L.) seedlings were measured in intact sand-filled columns, hydroponics, and disturbed sand-filled columns. Total nitrate uptake in intact sand-filled columns was higher than in disturbed columns, indicating that disturbance lowers uptake. Transferring plants from the sand-filled columns to hydroponics had little effect on NO3− uptake beyond delaying uptake for an hour. The second objective of this study was to determine whether NH4+, Ca2+, Mg2+ and K+ uptake could be studied using sand-filled columns, since previous studies had tested this method only for nitrate uptake. Uptake rates of NH4+ and K+ were positive, while Ca2+ and Mg2+ uptake rates were negative in intact sand-filled columns, indicating that net efflux may occur even without physical disturbance to the root system. The sand-filled column approach has some limitations, but holds promise for conducting nutrient uptake studies with minimal disturbance to the root system.
Lucash, Melissa S.; Yanai, Ruth D.; and Joslin, J. Devereux, "Nutrient Uptake by Intact and Disturbed Roots of Loblolly Pine Seedlings" (2008). Environmental Science and Management Faculty Publications and Presentations. 109.