Recent Topics Posters
Philip, Leanne J , Simard, Suzanne W. .
Minimum pulses of stable and radioactive carbon isotopes to detect belowground carbon transfer between plants.
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 13C or 14C in two separate laboratory experiments. Our specific objectives were: (1) to determine the minimum pulse of 13CO2 or 14CO2 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 13C and 14C pulse level. There was a tendency for the amount of interplant carbon transfer to increase with increasing 13C pulse level, but the same amount of transfer occurred at all 14C 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 13C or 0.19 MBq of 14C is sufficient to detect belowground carbon transfer in small seedlings growing in close proximity.
Log in to add this item to your schedule
1 - University of British Columbia, Forest Sciences, 2424 Main Mall, Vancouver, British Columbia, V6T1Z4, Canada
2 - The University of British Columbia, Forest Sciences, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
Presentation Type: Recent Topics Poster
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM