Dissertation Research: Black Birch Seedlings as Foragers forNitrogen

森林的再生取决于 个别树木，这是直接影响土壤氮 空房的 土壤氮素分布不均匀， 在铵：硝酸盐比率和总量方面。 先前 研究表明，黑桦树幼苗的表现与 与铵相比， 响应随供氮速率和光照水平而变化。 使用分裂罐设计来创建不同铵的补丁 硝酸盐定量，调查人员将检查是否黑色 桦树幼苗对硝酸盐或铵有选择性地觅食， 土壤 通过使用标记的15NO3，他们将测试根是否 实际上更喜欢获得铵，以及是否偏好 氮的给定形式取决于铵与氮的比率。 氮素供应速率、光照条件 空房的 最后，调查人员将审查是否 总非结构性碳水化合物：游离氨基酸的比例 叶片是整个植物分配的一个很好的预测因子， 生物质。

Forest regeneration is dependent on the successful growth of individual trees, which are directly affected by soil nitrogen availability. Soil nitrogen is heterogeneously distributed, both in terms of ammonium:nitrate ratio and total quantity. Previous work has shown that black birch seedlings perform differently when fed nitrate in comparison with ammonium, and that this response varies with rate of nitrogen supplied and light level. Using a split pot design to create patches of different ammonium to nitrate ration, the investigators will examine whether black birch seedlings forage selectively for nitrate or ammonium in soil. By using labelled 15NO3, they will test whether roots actually prefer to acquire ammonium, and whether preference for a given form of nitrogen is dependent upon the ratio of ammonium to nitrate in a patch, the rate of nitrogen supply and light availability. Lastly, the investigators will examine whether the ratio of total non-structural carbohydrates: free amino acids in the leaves is a good predictor of whole plant partitioning of biomass.