Responses of leaf functional traits and nitrogen and phosphorus stoichiometry in Abies fabiri seedlings in Gongga Mountain to simulated nitrogen deposition
Abies fabiri is one of the dominant conifers in the subalpine area of western Sichuan Province, Southwest China. Taking A. Fabiri seedlings as test materials, this paper studied their leaf functional traits and N and P stoichiometry under effects of simulated nitrogen deposition. To simulate nitrogen deposition, ammonium nitrate solution (50 kg N ? Hm-2? A-1) was weekly sprayed over the growth season (from May to October) of 2009 and 2010. After the two growth seasons, the total biomass, leaf dry weigh, leaf mass ratio, leaf N and P concentrations, and leaf N:P ratio of the seedlings under ammonium nitrate spraying increased by 11. 29% , 46. 70% , 41.40% , 37. 30% , 22. 33% and 6. 43% , respectively, while specific leaf area (SLA) de creased by 6. 61% , as compared with the control. There existed significant differences in the leaf dry weigh, leaf mass ratio, leaf N concentration, and leaf N : P ratio between ammonium nitrate spraying and the control, and the leaf dry weight had a strong linear correlation with leaf N con centration. The total biomass, leaf dry weight, leaf N and P concentrations, and leaf N : P ratio of seedlings under ammonium nitrate spraying were higher in the second growth season than in the first growth season. This study demonstrated that nitrogen deposition promoted the leaf growth of A. Fabiri seedlings significantly, and increased the leaf N and P concentrations and leaf N : P ratio. However, the variation of leaf N : P ratio under nitrogen supply suggested that the seedling growth was still limited by the shortage of N supply. It was suggested that A. Fabiri seedlings had cumulative effect for N.
nitrogen depositionN and P stoichiometryAbies fabiriseedling growthGongga Mountain
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维普
