A pulse-labelling method to generate 13C- enriched plant materials

摘要: Plant materials labelled with 13C can be used to trace litter decomposition and root carbon flow, but only if the isotope is uniformly distributed in plant. We postulated that 13CO2 were applied at regular intervals, direct proportion rate of photosynthesis, then abundance would uniform among plant parts. To test this hypothesis, wheat plants grown greenhouse, exposed weekly for six hours a closed chamber. A constant dose (about 33 atom%) was injected whenever CO2 concentration fell below prescribed limit, so added photosynthetic rate. Wheat 13 weeks (starting 11 days after seeding) had reasonably consistent parts: grain = 3.41, chaff stem 3.65, 3.50 atom%. The `leaf' fraction slightly higher (3.99 atom%), perhaps because recently-fixed not translocated from senescing tissue. Exposing during early stages growing season increased differences approach offers practical way label 13C.