Koch George W, Bloom Arnold J, Chapin F Stuart
Department of Vegetable Crops, University of California, 95616, Davis, CA, USA.
Department of Integrated Biology, University of California, 94720, Berkeley, CA, USA.
Oecologia. 1991 Dec;88(4):570-573. doi: 10.1007/BF00317721.
We compared ammonium and nitrate nutrition in Eriophorum scheuchzeri and E. vaginatum, two Alaskan sedges that are native to high- and low-fertility sites, respectively. When grown in solution culture, the two species were similar in their kinetics of NH NO absorption: at nitrogen concentrations below 50 μM, net NH and NO were absorbed at similar rates, but at higher concentrations, net uptake of NO was significantly faster than that of NH . The two species also showed similar abilities to assimilate NO . Growth of E. vaginatum under NO nutrition was only slightly less than that under NH . The observed similarities between these species from contrasting edaphic habitats indicate that factors other than tissue-specific rates of nitrogen acquisition and assimilation may underlie local adaptation to soil N fertility. Moreover, the capacity of these species to exploit NO as a N source supports the view that NO availability may be significant even in wet, acidic, arctic soils.
我们比较了阿拉斯加苔草中的铵态氮和硝态氮营养，其中两种苔草分别原产于高肥力和低肥力地区。在溶液培养中生长时，这两个物种对NH₄⁺和NO₃⁻的吸收动力学相似：在氮浓度低于50μM时，净NH₄⁺和NO₃⁻的吸收速率相似，但在较高浓度下，NO₃⁻的净吸收明显快于NH₄⁺。这两个物种同化NO₃⁻的能力也相似。在硝态氮营养下，毛果苔草的生长仅略低于铵态氮营养下的生长。这些来自不同土壤生境的物种之间观察到的相似性表明，除了组织特异性的氮获取和同化速率外，其他因素可能是当地对土壤氮肥力适应的基础。此外，这些物种利用NO₃⁻作为氮源的能力支持了这样一种观点，即即使在潮湿、酸性的北极土壤中，NO₃⁻的有效性也可能很重要。
