Day and night warming have different effect on root lifespan
Day and night warming have different effect on root lifespan
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昼夜变暖对根系寿命的影响不同
DOI：
10.5194/bg-9-375-2012
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发表时间：
2012-01-01
期刊：
影响因子：
4.9
通讯作者：
Li, L. H.
中科院分区：
文献类型：
--
作者：
Bai, W. M.;Xia, J. Y.;Li, L. H.
抽象。根系是陆地生态系统碳循环的重要组成部分，在调节陆地生态系统对全球气候变暖的响应中起着重要作用。然而，目前还没有详细的研究，调查不对称变暖对根系动态的影响，在陆地生态系统的水平。为了解昼夜增温对中国北方半干旱温带草原植物根系寿命的影响，采用改良的根管技术，在2007-2009年3个生长季采用全因子设计，包括对照、昼夜增温、昼夜增温和连续增温4个处理。结果表明，白天、夜间和持续增温对春、夏、秋三季根系寿命的影响不同，白天增温显著延长了三季根系的总体寿命，而夜间增温对总体寿命没有影响。昼夜增温对根系非结构性碳水化合物含量的影响不同，说明光合同化物的分配可能是根系寿命对昼夜增温的不同响应。这些结果不同于与生态系统碳循环相关的其他过程，如生态系统总生产力、生态系统净生产力和土壤呼吸。我们的研究结果强调，它是必不可少的，以模拟和预测陆地生态系统C循环对全球变暖的响应和反馈，将昼夜变暖对根系动态的差异影响。
Abstract. Roots are key components of C cycling in terrestrial ecosystems and play an important role in the regulation of response of terrestrial ecosystems to global climate warming, which is predicted to occur with greater warming magnitudes at night than during daytime across different regions on the Earth. However, there has been no detailed study to investigate the effect of asymmetrical warming on root dynamics at the level of terrestrial ecosystems. To understand the effects of day and night warming on root lifespan in the semiarid temperate steppe in northern China, a field study with a full factorial design including control, day warming, night warming and continuous warming was conducted using modified rhizotron technique during three growing seasons in 2007–2009. Our results show that day, night and continuous warming had different effects on longevity of roots born in spring, summer and autumn, and that day warming significantly prolonged overall lifespan for the roots born in the three growing seasons, while night warning had no effect on overall lifespan. Day and night warming had different effects on root non-structural carbohydrate content, suggesting that allocation of photoassimilate may account for the differential responses of root lifespan to day and night warming. These results differ from other processes associated with ecosystems C cycle such as total ecosystem productivity, net ecosystem productivity and soil respiration. Our findings highlight that it is essential to incorporate the differential effects of day and night warming on root dynamics into simulating and predicting the responses and feedbacks of terrestrial ecosystems C cycling to global warming.