OUP accepted manuscript
OUP accepted manuscript
复制标题
DOI：
10.1093/treephys/tpab152
复制
发表时间：
2021
期刊：
影响因子：
4
通讯作者：
中科院分区：
文献类型：
--
作者：
大气氮（N）沉降和降水增加影响陆地生态系统的碳固存，但这两个并发的全球变化变量如何影响树木的木质部生长（即，独立地或交互地）仍然不清楚。我们在中国中部进行了新的实验，以监测木质部生长的优势种（栎acutissimaCaruth。）与未处理对照（C）相比，氮添加（CN）、补充降水（CW）或两者处理（CNW）对水稻生长的影响更大。在2014-15年期间，每周进行一次测量。我们发现，在2015年干燥的春季，补充降水显著增强了木质部的生长，这表明降水增加对年内木质部生长的影响是随时间变化的。高氮处理对早材导管的木质部生长量、木质部生长速率、导管内径和潜在导水率（Ks）均无显著影响，但Ks与木质部生长量呈显著负相关。在2015年干旱春季，额外的N和补充降水的组合抑制了补充降水对木质部生长的正效应。这些研究结果表明，木质部宽度是更响应于补充降水比增加氮在干燥的早期生长季节，补充降水对木质部生长的积极影响可以抵消升高的N资源。氮素添加和降水补充的负交互作用也表明，未来增加氮沉降和降水可能会影响Q的固碳。acutissima在中国中部的早期生长季节。氮添加和补充降水对树木生长的影响是复杂的，可能会因生长期和当地气候条件而异。因此，未来的树木生长模型在模拟和预测全球变化时需要考虑多时间尺度和当地气候条件。
Atmospheric nitrogen (N) deposition and increasing precipitation affect carbon sequestration in terrestrial ecosystems, but how these two concurrent global change variables affect xylem growth in trees (i.e., independently or interactively) remains unclear. We conducted novel experiments in central China to monitor the xylem growth in a dominant species (Quercus acutissimaCaruth.) in response to N addition (CN), supplemental precipitation (CW) or both treatments (CNW), compared with untreated controls (C). Measurements were made at weekly intervals during 2014–15. We found that supplemental precipitation significantly enhanced xylem growth in the dry spring of 2015, indicating a time-varying effect of increased precipitation on intra-annual xylem growth. Elevated N had no significant effect on xylem increment, xylem growth rate, and lumen diameters and potential hydraulic conductivity (Ks) of earlywood vessels, butKswith elevated N was significantly negatively related to xylem increment. The combination of additional N and supplemental precipitation suppressed the positive effect of supplemental precipitation on xylem increment in the dry spring of 2015. These findings indicated that xylem width was more responsive to supplemental precipitation than to increasing N in a dry early growing season; the positive effect of supplemental precipitation on xylem growth could be offset by elevated N resources. The negative interactive effect of N addition and supplemental precipitation also suggested that increasing N deposition and precipitation in the future might potentially affect carbon sequestration ofQ. acutissimaduring the early growing season in central China. The effects of N addition and supplemental precipitation on tree growth are complex and might vary depending on the growth period and local climatic conditions. Therefore, future models of tree growth need to consider multiple-time scales and local climatic conditions when simulating and projecting global change.