Studying Phloem Loading with EDTA-Facilitated Phloem Exudate Collection and Analysis
Sugars that are produced by photosynthesis in the leaves are transported in the phloem to heterotrophic sink tissues like roots, fruit, or flowers. Since sugars inside the highly specialized cells of the phloem move by bulk flow, it is the loading and unloading of sugars that determines the rates of allocation between organs. Here, a method is described for the relative quantification of sugars that are loaded into the phloem in leaves. It is based on EDTA-facilitated phloem exudate collection and, therefore, requires control experiments to exclude measurement artifacts. It can be applied to a wide range of plant species, including dicots, monocots, and trees.
Key wordsPhloem Phloem loading EDTA-facilitated exudation Carbohydrate allocation Sucrose transport
- 8.Hoffmann-Benning S, Gage DA, McIntosh L, Kende H, Zeevaart JA (2002) Comparison of peptides in the phloem sap of flowering and non-flowering Perilla and lupine plants using microbore HPLC followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometr. Planta 216:140–147CrossRefGoogle Scholar
- 9.Tetyuk O, Benning UF, Hoffmann-Benning S (2013) Collection and analysis of Arabidopsis phloem exudates using the EDTA-facilitated method. J Vis Exp 80:e51111Google Scholar
- 15.Yadav UP, Khadilkar AS, Shaikh MA, Turgeon R, Ayre BG (2017) Assessing rates of long-distance carbon transport in Arabidopsis by collecting phloem exudations into edta solutions after photosynthetic labeling with [14C]CO2. Bio Protoc 7(24):e2656Google Scholar