Seasonal patterns in nitrogen and phosphorus and resorption in leaves of four tree species
4种阔叶树种叶中氮和磷的季节动态及其转移(英文)

The leaves of evergreen Castanopsis cuspidata (Thunb.) Schottky and Ilex pedunculosa Miq and deciduous Quercus serrata Murr., Quercus variabilis Blume were collected from the time of full leaf expansion to the end of growing season to describe the seasonal patterns of concentrations and contents of N and P in leaves of these species. N and P resorption rates from the leaves of the four species were also measured. The concentrations of N and P in leaves of deciduous Q. serrata and Q. variabilis and P concentration in new leaves of evergreen C. cuspidata were the highest at the first sampling data, and then tended to decrease with time, whereas N concentration in new leaves of evergreen C. cuspidata and concentrations of N and P in new leaves of evergreen I. pedunculosa decreased from maximum and then increased during the growing season. The changes of N and P concentrations in old leaves of C. cuspidata and I. pedunculosa were small. Both leaf type and sampling time significantly affected leaf nutrient concentrations. The maximums of N and P concentrations for new leaves of the evergreen species agree with their litter peak. The seasonal patterns of N and P concentrations on percentage of dry weight basis were generally similar to N and P contents on leaf area basis. Mean N resorption in the deciduous species was higher than in the evergreen species, whereas their P resorption was similar. There is lower resorption for N than for P, suggesting compared with N, all species translocated greater percentage P out of senescing leaves.