Leaf nutrient resorption of two life-form tree species in urban gardens and their response to soil nutrient availability

Abstract

Background Leaf nutrient resorption is a key strategy in plant conservation that minimizes nutrient loss and enhances productivity. However, the differences of the nutrient resorption among garden tree species in urban ecosystems were not clearly understood, especially the differences of nitrogen resorption efficiency (NRE) and phosphorous resorption efficiency (PRE) between evergreen and deciduous trees. Methods We selected 40 most generally used garden tree specie belonged two life forms (evergreen and deciduous) and investigated the nitrogen (N) and phosphorus (P) concentrations in green and senesced leaves and soil nutrient concentrations of nine samples trees for each species. Then, the nutrient concentrations and resorption efficiency were compared, and the soil nutrients utilization strategies were further analyzed. Results The results showed that the N concentration was significantly higher in the green and senesced leaves of deciduous trees than in the leaves of evergreen trees. The two life-form trees were both N limited and evergreen trees were more sensitive to N limitation. The NRE and PRE in the deciduous trees were significantly higher than those in the evergreen trees. The NRE was significantly positively correlated with the PRE in the deciduous trees. As the soil N and P concentrations increased, the nutrient resorption efficiency (NuRE) of the evergreen trees increased, but that of the deciduous trees decreased. Compared with the deciduous trees, the evergreen trees were more sensitive to the feedback of soil N and P concentrations. These findings reveal the N and P nutrient resorption mechanism of evergreen and deciduous trees and fill a gap in the understanding of nutrient resorption in urban ecosystems.

Nutrient resorption efficiency of Heritiera fomes Buch. Ham and Excoecaria agallocha L

“…Element resorption is related to the leaf senescence and nutrient conservation, and reusing these nutrients is an important mechanism for tree survival in nutrient-poor environments (Pugnaire and Chapin 1993). At different stages of foliage development, nutrient resorption from leaves is critical for the supply of N, P, and K to the new growth in tree species (Saur et al 2000;van Heerwaarden et al 2003;Hu et al 2023). Before abscission and loss, nutrient uptake and soil fertility cause nutrients to be relocated to younger leaves (Reef et al 2010).…”