Simard Suzanne W, Jones Melanie D, Durall Daniel M, Perry David A, Myrold David D, Molina Randy
Research Section, Kamloops Forest Region, British Columbia Ministry of Forests, 515 Columbia Street, Kamloops, B.C., V2C 2T7, Canada.
Biology Department, Okanagan University College, 3333 College Way, Kelowna, B.C., VIV 1V7, Canada.
New Phytol. 1997 Nov;137(3):529-542. doi: 10.1046/j.1469-8137.1997.00834.x.
Interspecific C transfer was studied in laboratory microcosms containing pairs of 6-month-old Betula papyrifera Marsh, and Pseudotsuga menziesii (Mirb.) Franca seedlings growing in individual, root-restrictive (28μm pore size) pouches filled with field soil. Interspecific transfer was examined by reciprocal labelling of seedlings with CO and CO . At the time of labelling, the root zones of ectomycorrhizal (EM) B. papyrifera and P. menziesii were interconnected by an extensive network of EM mycelium. Carbon transferred through EM connections was distinguished from that through soil pathways by comparing microcosms where interconnecting hyphae were left intact vs. those where they were severed immediately before labelling. Transfer was bidirectional, and represented 5 % of total isotope uptake by both B. papyrifera and P. menziesii together. P. menziesii received on average 50% more C and 66% more C from paper birch than vice versa, however, differences between species were not statistically significant. Neither net nor bidirectional transfer differed between severing treatments, leaving in question the relative importance of EM hyphae versus soil transfer pathways. The tendency for P. menziesii to receive more isotope than B. papyrifera corresponded with a 10-fold greater net photosynthetic rate per seedling and two-fold greater foliar N concentration of B. papyrifera than P. menziesii.
在实验室微观世界中研究了种间碳转移，该微观世界包含成对的6个月大的纸皮桦（Betula papyrifera Marsh）和花旗松（Pseudotsuga menziesii (Mirb.) Franca）幼苗，它们生长在装满田间土壤的单独的、限制根系生长（孔径28μm）的袋子里。通过用¹³CO₂和¹⁴CO₂对幼苗进行相互标记来检测种间转移。在标记时，外生菌根（EM）纸皮桦和花旗松的根区通过广泛的EM菌丝网络相互连接。通过比较标记前将连接菌丝保持完整的微观世界与将连接菌丝立即切断的微观世界，区分了通过EM连接转移的碳和通过土壤途径转移的碳。转移是双向的，占纸皮桦和花旗松共同总同位素吸收量的5%。花旗松从纸皮桦平均接收的¹³C多50%，¹⁴C多66%，反之则相反，然而，物种间的差异没有统计学意义。切断处理之间的净转移和双向转移均无差异，这使得EM菌丝与土壤转移途径的相对重要性存疑。花旗松比纸皮桦接收更多同位素的趋势与每株幼苗净光合速率高10倍以及纸皮桦叶片氮浓度比花旗松高两倍相对应。
