ISSN:
1573-5036
Keywords:
carbon flow
;
14C labeling
;
carbon allocation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract A14C labeling apparatus was developed to permit the labeling of four-year-old Ponderosa pine with14CO2 in the field. The labeling system is a completely closed canopy system with14CO2 monitored by a GM tube ratemeter apparatus. The level of14CO2 corresponding to ambient levels is monitored by a microloggercomputer which controls a14CO2 generating system. The generated14CO2 is mixed in the canopy by circulating the atmosphere with 12V diaphram pumps. The portable system requires little operator attention. At approximately monthly intervals over a one-year period two four-year-old Ponderosa pine trees were labeled for three to five days using this labeling apparatus. After an assimilate distribution period, one tree was excavated and analyzed for14C distribution. During late spring and early summer most of the carbon assimilated (〉60%) was found in the active growing tips and new needles, with little being allocated to the roots (〈10%) or woody material (〈20%). During mid to late fall there was an increase in root labeling along with an increase in carbon going to woody material. Over the winter period, most of the fixed carbon (65%) resided in the older leaves. The early spring labeling period showed another pulse of root labeling along with some labeling of woody tissues.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02371217
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