ISSN:
1432-2285
Keywords:
Carbon allocation
;
14C labelling
;
Long-term experiments
;
Scots pine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary 14CO2 at ambient concentration was administered to a section of an upper branch of 8-year-old Scots pines and the import of radiocarbon into the stem and roots was determined after various chase periods. 14CO2 fixation was performed in October when export of carbon into the stems and roots was maximal. In the short-term experiments the trees were harvested 1 h, 2 days and 5 days after a 3-h 14C pulse, while chase periods of 5 or 8 months were used in the long-term experiments. Loss of 14C was initially substantial, and even after a 5-day chase had not come down to a rate which indicated decrease only by respiration. After 5 days, more than 10% of the recovered radiocarbon (53% of the 14C translocated into the stem) had entered the roots and approximately the same amount was found in the stem. Extension of the chase period beyond 5 months did not result in a further significant loss of 14C by respiration, and the bulk of the label could be localized in the cell-wall fraction. No substantial redistribution of radiocarbon prior and subsequent to the formation of the new shoots could be observed, thus indicating that the stored material was utilized for thickening the stem and roots. Radioautography of stem cross-sections revealed a narrow helical strip of 14C from the feeding branch to the root in the phloem region. In the tree harvested after bud break the utilization of the 14C-labelled material stored in the stem for the production of the first layers of earlywood and the corresponding phloem was apparent.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00226235
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