Recently, I was at the MPI-Jena helping Claudia Winters, Gerd Gleixner and his PhD student, Ronny. We were exploring different techniques to sample phloem on-line followed by isotopic analysis of the samples by LC-IRMS. The temporal dynamics between canopy physiology and belowground respiration as mediated by phloem transport remains a mystery. Isotopic techniques[1], statistical investigations [2], and modeling [3] have been employed to tease out the canopy-phloem-rhizosphere connection; I had a short letter regarding these approaches. In the meantime, we are still waiting for direct measurements that can be sampled over the day......
Footnotes:
You can also see Kayler et al., 2010 for a brief discussion of phloem transport and canopy-soil interactions.
