A simple urea leaf-feeding method for the production of 13C and 15N labelled plant material
- Cite this article as:
- Schmidt, O. & Scrimgeour, C.M. Plant and Soil (2001) 229: 197. doi:10.1023/A:1004815404197
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The use of 13C isotope tracer techniques in terrestrial ecology has been restricted by the technical requirements and high costs associated with the production of 13C enriched plant material by 13CO2 release in labelling chambers. We describe a novel, simple and relatively inexpensive method for the small-scale production of 13C and 15N labelled plant material. The method is based on foliar feeding of plants with a urea solution (97 atom% 13C, 2 atom% 15N) by daily misting. Maize was grown in a greenhouse in a compost–soil mixture and enclosed in clear polythene bags between urea applications. Final enrichment in 27 d old maize shoots was 211‰ δ13C (≈1.34 atom% 13C) and 434‰ δ15N (≈0.52 atom% 15N). Enrichments of hot-water extractable fractions (289‰ δ13C, 469‰ δ15N) were only slightly higher than those observed in plant bulk material, which suggests that daily urea applications ensured fairly uniform labelling of different biochemical fractions and plant tissues. Recovery of applied excess 13C and 15N in plant shoots was 22% and 42%, respectively. Roots were less enriched (21‰ δ13C and 277‰ δ15N), but no attempts were made to recover roots quantitatively.