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首页> 外文期刊>Catena: An Interdisciplinary Journal of Soil Science Hydrology-Geomorphology Focusing on Geoecology and Landscape Evolution >Root respiration and belowground carbon allocation respond to drought stress in a perennial grass (Bothriochloa ischaemum)
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Root respiration and belowground carbon allocation respond to drought stress in a perennial grass (Bothriochloa ischaemum)

机译：根呼吸和低于地碳分配对多年生草（Bothriochloa ischaemum）的干旱胁迫作出响应

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In order to accurately estimate the carbon (C) balance in arid and semi-arid grasslands, it is necessary to first understand how the demands of photosynthates and root carbon (C) are allocated in response to drought. To accomplish this goal, we used a C-13 pulse labeling technique to assess correlations between root morphology and the amount of C-13 in the root, which is a measure of respiration. We compared respiration changes via the excised root C-13 of Bothriochloa ischaemum at various root excision times (i.e., 0, 6, 24, 48, 216, and 360 h after labeling). Our results showed that C-13 and root respiration continued to increase until 216 h after labeling, and then they decreased after 360 h. Root respiration correlated significantly with the carbon labeled as being from the fine roots that were undergoing drought stress treatments. This indicates that later-photosynthates are the primary C source for root respiration. Fine root C-13 positively correlated with fine root biomass and specific root length under serious drought conditions. This suggests that fine root growth is based primarily on recently derived photosynthates. Serious drought was shown to inflate the root/shoot ratio by increasing both the C-13 and the biomass, which led to greater C allocation in the root system. Finally, the fine/coarse root ratios of C-13 and biomass were greatest in the serious drought treatment This suggests that fine roots have a higher C demand than coarse roots under drought stress. Fine root respiration was also found to stimulate new C demand in roots because the amount of C-13 created during root respiration was positively correlated with tissue N concentration of fine roots.
机译：为了准确估计干旱和半干旱草原中的碳（c）平衡，有必要首先了解光合素和根碳（c）的需求是如何应对干旱的影响。为了实现这一目标，我们使用了C-13脉冲标记技术来评估根形态与根系中的根形态与C-13的量之间的相关性，这是一种呼吸的量度。我们将呼吸变化与在各种根切除次数（即0,6,24,48,216和360h之后的各种根切除时间（即0,6,24,48,216和360小时）进行比较。我们的研究结果表明，在标记后，C-13和根呼吸持续增加，直至216小时，然后在360小时后减少。根部呼吸显着与标记为正在发生干旱胁迫处理的细根的碳相关。这表明稍后的光合酯是根呼吸的主要C源。细根C-13在严重干旱条件下与细根生物量和特异性根长呈正相关。这表明细根生长主要是基于最近衍生的光合素。通过增加C-13和生物质，显示了严重的干旱，通过增加C-13和生物质，这导致了根系系统中的C分配更大的C分配。最后，在严重的干旱处理中，C-13和生物质的细粒/粗根比最大，这表明细根具有比干旱胁迫下的粗根的C需求更高。还发现细根呼吸刺激根系中的新的C需求，因为在根呼吸期间产生的C-13的量与组织N浓度的细根呈正相关。

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