title: Phosphorus resorption by young beech trees and soil phosphatase activity as dependent on phosphorus availability.
abstract: Motivated by decreasing foliar phosphorus (P) concentrations in Fagus sylvatica L. forests, we studied P recycling depending on P fertilization in mesocosms with juvenile trees and soils of two contrasting F. sylvatica L. forests in a greenhouse. We hypothesized that forests with low soil P availability are better adapted to recycle P than forests with high soil P availability. The P resorption efficiency from senesced leaves was significantly higher at the P-poor site (70 %) than at the P-rich site (48 %). P fertilization decreased the resorption efficiency significantly at the P-poor site to 41 %, while it had no effect at the P-rich site. Both acid and alkaline phosphatase activity were higher in the rhizosphere of the P-poor than of the P-rich site by 53 and 27 %, respectively, while the activities did not differ in the bulk soil. Fertilization decreased acid phosphatase activity significantly at the P-poor site in the rhizosphere, but had no effect on the alkaline, i.e., microbial, phosphatase activity at any site. Acid phosphatase activity in the P-poor soil was highest in the rhizosphere, while in the P-rich soil, it was highest in the bulk soil. We conclude that F. sylvatica resorbed P more efficiently from senescent leaves at low soil P availability than at high P availability and that acid phosphatase activity in the rhizosphere but not in the bulk soil was increased at low P availability. Moreover, we conclude that in the P-rich soil, microbial phosphatases contributed more strongly to total phosphatase activity than plant phosphatases.
authors.affiliation: Department of Soil Ecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Hofmann
authors.affiliation: Department of Soil Ecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Heuck
authors.affiliation: Department of Soil Ecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany. marie.spohn@uni-bayreuth.de.
authors.forename: Marie
authors.initials: M
authors.lastname: Spohn
mesh_terms: D029964:Fagus; D009584:Nitrogen; D010744:Phosphoric Monoester Hydrolases; D010758:Phosphorus; D012987:Soil; D014197:Trees
chemical_list: D012987:Soil; D010758:Phosphorus; D010744:Phosphoric Monoester Hydrolases; D009584:Nitrogen
keywords: Forest nutrition; Nutrient resorption; Phosphomonoesterase; Plant–microbe interaction; Rhizosphere