利用木质部和韧皮部茎注射技术对斯提克云杉（Picea sitchensis）进行近期光合作用产物稳定同位素标记和探测，进入呼吸 CO2、土壤微生物和土壤中型土壤动物。
Stable-isotope labeling and probing of recent photosynthates into respired CO2, soil microbes and soil mesofauna using a xylem and phloem stem-injection technique on Sitka spruce (Picea sitchensis).
机构信息
Belowground Ecosystem Group, Department of Forest Sciences, University of British Columbia, Vancouver, B.C., Canada.
出版信息
Rapid Commun Mass Spectrom. 2012 Nov 15;26(21):2493-501. doi: 10.1002/rcm.6368.
RATIONALE
Here we report on the successful application of a novel stem-injection stable-isotope-labeling and probing technique in mature trees to trace the spatial and temporal distribution of rhizosphere carbon belowground.
METHODS
Three 22-year-old Sitka spruce trees were injected with 6.66 g of (13)C-labeled aspartic acid. Over the succeeding 30 days, soil CO(2) efflux, phospholipid fatty-acid (PLFA) microbial biomarkers and soil invertebrates (mites, collembolans and enchytraeids) were analyzed along a 50 m transect from each tree to determine the temporal and spatial patterns in the translocation of recently fixed photosynthates belowground.
RESULTS
Soil δ(13)CO(2) values peaked 13-23 days after injection, up to 5 m from the base of the injected tree and was, on average, 3.5‰ enriched in (13)C relative to the baseline. Fungal PLFA biomarkers peaked 2-4 days after stem-injection, up to 20 m from the base of the injected tree and were (13)C-enriched by up to 50‰. Significant (13)C enrichment in mites and enchytraeids occurred 4-6 days after injection (by, on average, 1.5‰).
CONCLUSIONS
Stem injection of large trees with (13)C-enriched compounds is a successful tool to trace C-translocation belowground. In particular, the significant (13)C enrichment of CO(2) and enchytraeids near the base of the tree and the significant (13)C enrichment of PLFAs up to 20 m away indicate that mature Sitka spruce (Picea sitchensis) have the capacity to support soil communities over large distances.
原理
本研究报告了一种新型的茎内注射稳定同位素标记和探测技术在成熟树木中的成功应用，用于追踪根际碳在地下的时空分布。
方法
将 6.66g 的（13）C 标记天冬氨酸注入 3 棵 22 岁的欧洲云杉中。在随后的 30 天内，分析了距每棵树 50 米的一条 50 米长的样带上的土壤 CO2 释放、磷脂脂肪酸（PLFA）微生物生物标志物和土壤无脊椎动物（螨、弹尾目和线蚓），以确定地下新固定光合产物的时空转移模式。
结果
土壤 δ13CO2 值在注射后 13-23 天达到峰值，距注射树的基部可达 5m，比基线平均富集 3.5‰（13）C。真菌 PLFA 生物标志物在茎内注射后 2-4 天达到峰值，距注射树的基部可达 20m，（13）C 富集高达 50‰。螨和线蚓在注射后 4-6 天（平均 1.5‰）出现显著的（13）C 富集。
结论
用（13）C 富集化合物对大树进行茎内注射是一种成功的追踪地下碳转移的工具。特别是，在树的基部附近 CO2 和线蚓的显著（13）C 富集，以及高达 20m 处的 PLFA 的显著（13）C 富集，表明成熟的欧洲云杉（Picea sitchensis）具有在远距离支持土壤群落的能力。
Zotero 插件