...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Evolutionary tradeoffs can select against nitrogen fixation and thereby maintain nitrogen limitation
【24h】

Evolutionary tradeoffs can select against nitrogen fixation and thereby maintain nitrogen limitation

机译：进化权衡可以选择不固氮，从而维持氮限制

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Symbiotic nitrogen (N) fixing trees are absent from old-growth temperate and boreal ecosystems, even though many of these are N-limited. To explore mechanisms that could select against N fixation in N-limited, old-growth ecosystems, we developed a simple resource-based evolutionary model of N fixation. When there are no costs of N fixation, increasing amounts of N fixation will be selected for until N no longer limits production. However, tradeoffs between N fixation and plant mortality or turnover, plant uptake of available soil N, or N use efficiency (NUE) can select against N fixation in N-limited ecosystems and can thereby maintain N limitation indefinitely (provided that there are losses of plant-unavailable N). Three key traits influence the threshold that determines how large these tradeoffs must be to select against N fixation. A low NUE, high mortality (or turnover) rate and low losses of plant-unavailable N all increase the likelihood that N fixation will be selected against, and a preliminary examination of published data on these parameters shows that these mechanisms, particularly the tradeoff with NUE, are quite feasible in some systems. Although these results are promising, a better characterization of these parameters in multiple ecosystems is necessary to determine whether these mechanisms explain the lack of symbiotic N fixers—and thus the maintenance of N limitation—in old-growth forests.
机译：生长温带和北方生态系统中没有共生固氮树，即使其中许多都是氮有限的。为了探索可以在N个有限的，较老的生态系统中选择针对N固定的机制，我们开发了一个基于资源的简单的N固定进化模型。当没有固氮成本时，将选择增加固氮量，直到固氮不再限制生产为止。但是，固氮与植物死亡率或更新率，植物对可用土壤氮的吸收或固氮利用效率（NUE）之间的权衡可以选择限制氮的生态系统中的固氮，从而无限期保持氮的限制（前提是存在氮素损失）。植物不可用N）。三个关键特征会影响阈值，该阈值决定了要针对N种注视进行选择时必须权衡的取舍范围。低的NUE，高的死亡率（或周转率）和植物无法利用的N的低损失都增加了选择N固定的可能性，对这些参数的公开数据的初步检查表明，这些机制，尤其是与N的权衡。 NUE，在某些系统中是完全可行的。尽管这些结果令人鼓舞，但是有必要在多个生态系统中更好地表征这些参数，以确定这些机制是否可以解释老龄森林中缺乏共生固氮剂，从而维持固氮限制。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号