Record ID No. |
2167 |
Author(s) |
Philip, LJ; Simard, SW. , 2008 |
Affiliation |
Simard SW, Univ British Columbia, Dept Forest Sci, 2424 Main Hall, Vancouver, BC V6T 1Z4, CANADA |
Title |
Minimum pulses of stable and radioactive carbon isotopes to detect belowground carbon transfer between plants |
Source. Vol.(no):Page |
Plant and Soil, 308(1-2): 23-35 |
Categories |
Ectomycorrhiza |
Subjects |
Biochemistry |
Sub-subjects |
Miscellaneous |
Country |
Canada, North America |
Abstracts |
Methodological problems, such as unwanted shifts in plant carbon allocation patterns following large isotopic labeling pulses, have hindered accurate quantification of belowground carbon movement in plant-soil systems. These problems must be addressed before we can understand the factors regulating carbon movement between plants and soils and the importance of this movement to the global carbon cycle. We studied the effects of pulse-label size on carbon allocation and transfer between ectomycorrhizal paper birch (Betula papyrifera Marsh.) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings using increasing pulse levels of either C-13 or C-14 in two separate laboratory experiments. Our specific objectives were: (1) to determine the minimum pulse of (CO2)-C-13 or (CO2)-C-14 for detecting carbon movement between plants through belowground transfer pathways, (2) to determine whether carbon allocation patterns within these plants change when exposed to short pulses of elevated carbon dioxide and, (3) to determine whether carbon allocation patterns are similar when using two different carbon isotopes. We detected carbon movement between plants at each C-13 and C-14 pulse level. There was a tendency for the amount of interplant carbon transfer to increase with increasing C-13 pulse level, but the same amount of transfer occurred at all C-14 pulses between 0.19 and 0.56 MBq. Carbon allocation patterns did not change with pulse level but they were affected by the choice of carbon isotope. We conclude that at least 8 ml of C-13 or 0.19 MBq of C-14 is sufficient to detect belowground carbon transfer in small seedlings growing in close proximity. |