Li Hailiang, C Crabbe M James, Xu Fuli, Wang Weiling, Ma Lihui, Niu Ruilong, Gao Xing, Li Xingxing, Zhang Pei, Ma Xin, Chen Haikui
College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, P. R. China.
Wolfson College, Oxford University, Oxford, United Kingdom.
PLoS One. 2017 Sep 22;12(9):e0185163. doi: 10.1371/journal.pone.0185163. eCollection 2017.
Understanding how concentrations of elements and their stoichiometry change with plant growth and age is critical for predicting plant community responses to environmental change. We used long-term field experiments to explore how the leaf, stem and root carbon (C), nitrogen (N) and phosphorous (P) concentrations and their stoichiometry changed with growth and stand age in a L. principis-rupprechtii Mayr. plantation from 2012-2015 in the Qinling Mountains, China. Our results showed that the C, N and P concentrations and stoichiometric ratios in different tissues of larch stands were affected by stand age, organ type and sampling month and displayed multiple correlations with increased stand age in different growing seasons. Generally, leaf C and N concentrations were greatest in the fast-growing season, but leaf P concentrations were greatest in the early growing season. However, no clear seasonal tendencies in the stem and root C, N and P concentrations were observed with growth. In contrast to N and P, few differences were found in organ-specific C concentrations. Leaf N:P was greatest in the fast-growing season, while C:N and C:P were greatest in the late-growing season. No clear variations were observed in stem and root C:N, C:P and N:P throughout the entire growing season, but leaf N:P was less than 14, suggesting that the growth of larch stands was limited by N in our study region. Compared to global plant element concentrations and stoichiometry, the leaves of larch stands had higher C, P, C:N and C:P but lower N and N:P, and the roots had greater P and C:N but lower N, C:P and N:P. Our study provides baseline information for describing the changes in nutritional elements with plant growth, which will facilitates plantation forest management and restoration, and makes a valuable contribution to the global data pool on leaf nutrition and stoichiometry.
了解元素浓度及其化学计量比如何随植物生长和年龄变化，对于预测植物群落对环境变化的响应至关重要。我们利用长期田间试验，探究了2012 - 2015年中国秦岭地区华北落叶松人工林中，叶片、茎和根的碳（C）、氮（N）和磷（P）浓度及其化学计量比如何随生长和林分年龄变化。我们的结果表明，落叶松林不同组织中的C、N和P浓度以及化学计量比受林分年龄、器官类型和采样月份的影响，并且在不同生长季节与林分年龄增加呈现多重相关性。一般来说，叶片C和N浓度在快速生长季节最高，但叶片P浓度在生长初期最高。然而，随着生长，未观察到茎和根中C、N和P浓度有明显的季节变化趋势。与N和P相比，器官特异性C浓度差异较小。叶片N:P在快速生长季节最高，而C:N和C:P在生长后期最高。在整个生长季节，茎和根的C:N、C:P和N:P未观察到明显变化，但叶片N:P小于14，这表明在我们的研究区域，落叶松林的生长受N限制。与全球植物元素浓度和化学计量比相比，落叶松林的叶片具有较高的C、P、C:N和C:P，但较低的N和N:P，而根具有较高的P和C:N，但较低的N、C:P和N:P。我们的研究为描述营养元素随植物生长的变化提供了基线信息，这将有助于人工林的管理和恢复，并为全球叶片营养和化学计量比数据库做出了有价值的贡献。
