Nutritional constraints in ombrotrophic Sphagnum plants under increasing atmospheric nitrogen deposition in Europe
Nutritional constraints in ombrotrophic Sphagnum plants under increasing atmospheric nitrogen deposition in Europe
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DOI：
10.1111/j.1469-8137.2004.01154.x
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发表时间：
2004-09-01
期刊：
影响因子：
9.4
通讯作者：
Gerdol, R
中科院分区：
文献类型：
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作者：
Bragazza, L;Tahvanainen, T;Gerdol, R
以11个欧洲国家的15个沼泽为研究对象，研究了大气氮沉降水平的增加对富营养型泥炭草营养限制的影响。根据在丘陵(即相对干燥的微生境)和草坪(即相对潮湿的微生境)采集的泥炭草属植物的N、P(P)和K(K)的营养比来评估营养约束。在低大气N输入时，泥炭草属植物的营养比急剧增加，但超过1g/m(2)年的N沉积阈值(-1)，N：P和N：K比趋于饱和。大气氮沉降的增加还伴随着泥炭藓植物对钙和镁的保持减少，以及沼泽泥炭藓植物茎体积密度的下降。我们建议欧洲泥炭疽植物的N沉降临界负荷为1g/m(2年)年(-1年)，超过这个临界值，泥炭藓植物在N：P>；30和N：K>；3时从N受限转变为K+P限制。
We studied the effects of increasing levels of atmospheric nitrogen (N) deposition on nutrient limitation of ombrotrophic Sphagnum plants.Fifteen mires in 11 European countries were selected across a natural gradient of bulk atmospheric N deposition from 0.1 to 2 g/m(2) year(-1). Nutritional constraints were assessed based on nutrient ratios of N, phosphorus (P), and potassium (K) in Sphagnum plants collected in hummocks (i.e. relatively drier microhabitats) and in lawns (i.e. relatively wetter microhabitats).Nutrient ratios in Sphagnum plants increased steeply at low atmospheric N input, but above a threshold of N deposition of c. 1 g/m(2) year(-1) the N : P and N : K ratios tended to saturation. Increasing atmospheric N deposition was also accompanied by a reduced retention of Ca and Mg in Sphagnum plants and a decreased stem volumetric density in hummock Sphagnum plants.We suggest a critical load of N deposition in Europe of 1 g/m(2) year(-1) above which Sphagnum plants change from being N-limited to be K + P colimited, at N : P > 30 and N : K > 3.