Contribution of new photosynthetic assimilates to respiration by perennial grasses and shrubs: residence times and allocation patterns
Contribution of new photosynthetic assimilates to respiration by perennial grasses and shrubs: residence times and allocation patterns
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DOI：
10.1111/j.1469-8137.2007.02153.x
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发表时间：
2007-01-01
期刊：
影响因子：
9.4
通讯作者：
Trumbore, Susan E.
中科院分区：
文献类型：
--
作者：
Carbone, Mariah S.;Trumbore, Susan E.
对植物代谢所使用的碳 (C) 的归宿进行量化对于改善对陆地生态系统呼吸及其来源的预测是必要的。这里，使用双同位素（C-13 和 C-14）脉冲标签来确定美国加利福尼亚州欧文斯谷的两种植物功能类型（多年生草本植物和灌木）在生长季早期和晚期新 C 向不同呼吸途径的分配。植物类型之间的分配差异超过了季节性分配变化。在生长季节的早期和晚期，草的呼吸量分别为 71% 和 64%，灌木的呼吸量分别为 22% 和 17%。跨季节和植物类型，回收的标签中大约 48-61% 在标记后 24 小时内被呼吸，大约 68-84% 在标记后 6 天内被呼吸，大约 16-33% 在标记后 6-36 天内被呼吸。 确定了三个用于植物代谢的 C 池：快速池，其平均停留时间 (MRT) 分别类似于 0.5 和地下和地上 1 天； MRT 为 19.9 和 18.9 天的中间池；和同化后 > 9 个月在新叶早期生长季节呼吸中检测到的储存池。快速与中速 C 库的分配差异导致灌木呼吸的 C 平均年龄（3.8-4.5 天）比草本（4.8-8.2 天）短。
Quantification of the fate of carbon (C) used by plant metabolism is necessary to improve predictions of terrestrial ecosystem respiration and its sources.Here, a dual isotope (C-13 and C-14) pulse-label was used to determine the allocation of new C to different respiratory pathways in the early and late growing seasons for two plant functional types, perennial grasses and shrubs, in the Owens Valley, CA, USA.Allocation differences between plant types exceeded seasonal allocation variation. Grasses respired 71 and 64% and shrubs respired 22 and 17% of the label below-ground in the early and late growing seasons, respectively. Across seasons and plant types, similar to 48-61% of the label recovered was respired in 24 h, similar to 68-84% in 6 d, and similar to 16-33% in 6-36 d after labeling.Three C pools were identified for plant metabolism: a fast pool with mean residence times (MRTs) of similar to 0.5 and similar to 1 d below- and above-ground, respectively; an intermediate pool with MRTs of 19.9 and 18.9 d; and a storage pool detected in new leaf early growing season respiration > 9 months after assimilation. Differences in allocation to fast vs intermediate C pools resulted in the mean age of C respired by shrubs being shorter (3.8-4.5 d) than that of the grasses (4.8-8.2 d).