College of Life Science and Biotechnology, Mianyang Normal University, Mianyang, China.
Chair of Tree Physiology, Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.
PLoS One. 2018 Mar 22;13(3):e0194684. doi: 10.1371/journal.pone.0194684. eCollection 2018.
The coniferous forest tree Douglas-fir (Pseudotsuga menziesii) is native to the pacific North America, and is increasingly planted in temperate regions worldwide. Nitrogen (N) metabolism is of great importance for growth, resistance and resilience of trees. In the present study, foliar N metabolism of adult trees of three coastal and one interior provenance of Douglas-fir grown at two common gardens in southwestern Germany (Wiesloch, W; Schluchsee, S) were characterized in two subsequent years. Both the native North American habitats of the seed sources and the common garden sites in Germany differ in climate conditions. Total and mineral soil N as well as soil water content were higher in S compared to W. We hypothesized that i) provenances differ constitutively in N pool sizes and composition, ii) N pools are affected by environmental conditions, and iii) that effects of environmental factors on N pools differ among interior and coastal provenances. Soil water content strongly affected the concentrations of total N, soluble protein, total amino acids (TAA), arginine and glutamate. Foliar concentrations of total N, soluble protein, structural N and TAA of trees grown at W were much higher than in trees at S. Provenance effects were small but significant for total N and soluble protein content (interior provenance showed lowest concentrations), as well as arginine, asparagine and glutamate. Our data suggest that needle N status of adult Douglas-fir is independent from soil N availability and that low soil water availability induces a re-allocation of N from structural N to metabolic N pools. Small provenance effects on N pools suggest that local adaptation of Douglas-fir is not dominated by N conditions at the native habitats.
针叶林树种花旗松（Pseudotsuga menziesii）原产于北美太平洋沿岸，现已广泛种植于世界各地的温带地区。氮（N）代谢对树木的生长、抗性和恢复力具有重要意义。本研究以德国西南部两个普通花园（Wiesloch，W；Schluchsee，S）生长的三个沿海和一个内陆种源的成年花旗松为研究对象，连续两年对其叶片 N 代谢进行了特征描述。种子来源的北美原生栖息地和德国的普通花园在气候条件上存在差异。与 W 相比，S 的土壤总氮和矿质氮以及土壤含水量更高。我们假设：i）种源在 N 库大小和组成上存在固有差异，ii）N 库受环境条件的影响，iii）环境因素对 N 库的影响在内部和沿海种源之间存在差异。土壤含水量强烈影响总 N、可溶性蛋白、总氨基酸（TAA）、精氨酸和谷氨酸的浓度。在 W 生长的树木的叶片总 N、可溶性蛋白、结构 N 和 TAA 浓度远高于在 S 生长的树木。种源效应虽小但显著，表现在总 N 和可溶性蛋白含量（内陆种源浓度最低）、精氨酸、天冬酰胺和谷氨酸上。我们的数据表明，成年花旗松的针叶 N 状况与土壤 N 供应无关，低土壤水分供应会导致 N 从结构 N 重新分配到代谢 N 库。N 库的种源效应较小，表明花旗松的本地适应性并非主要受原生境 N 条件的影响。
