High temporal resolution tracing of photosynthate carbon from the tree canopy to forest soil microorganisms
High temporal resolution tracing of photosynthate carbon from the tree canopy to forest soil microorganisms
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DOI：
10.1111/j.1469-8137.2007.02238.x
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发表时间：
2008-01-01
期刊：
影响因子：
9.4
通讯作者：
Nasholm, T.
中科院分区：
文献类型：
--
作者：
Hogberg, P.;Hogberg, M. N.;Nasholm, T.
森林土壤中一半的生物活性是由最近的树木光合作用支持的，但没有研究详细追踪这种从树冠到田间土壤微生物的碳通量。我们脉冲标记了一个200米（3）高的北方樟子松林的50米（2）斑块超过1.5小时。在0.3 m高度的韧皮部中可溶性碳水化合物中，示踪剂水平在2-4 h后达到峰值，在土壤呼吸流出中，在4-7 d后达到峰值，在外生菌根根中，在2-4 d后达到峰值。针叶活性库中的碳、韧皮部可溶性碳水化合物中的碳和土壤呼吸流出物中的碳的半衰期分别为22、17和35 h。土壤微生物细胞质中碳的半衰期为280 h，而外生菌根根尖中的碳周转较慢。同时标记的土壤与（NH 4+）-N-15表明，外生菌根根，这是最强的光合作用，也是最活跃的socks.These观察突出了密切的时间耦合树冠光合作用和土壤活动的显着部分在森林。
Half of the biological activity in forest soils is supported by recent tree photosynthate, but no study has traced in detail this flux of carbon from the canopy to soil microorganisms in the field.Using (CO2)-C-13, we pulse-labelled over 1.5 h a 50-m(2) patch of 4-m-tall boreal Pinus sylvestris forest in a 200-m(3) chamber.Tracer levels peaked after 24 h in soluble carbohydrates in the phloem at a height of 0.3 m, after 2-4 d in soil respiratory efflux, after 4-7 d in ectomycorrhizal roots, and after 2-4 d in soil microbial cytoplasm. Carbon in the active pool in needles, in soluble carbohydrates in phloem and in soil respiratory efflux had half-lives of 22, 17 and 35 h, respectively. Carbon in soil microbial cytoplasm had a half-life of 280 h, while the carbon in ectomycorrhizal root tips turned over much more slowly. Simultaneous labelling of the soil with (NH4+)-N-15 showed that the ectomycorrhizal roots, which were the strongest sinks for photosynthate, were also the most active sinks for soil nitrogen.These observations highlight the close temporal coupling between tree canopy photosynthesis and a significant fraction of soil activity in forests.