Simultaneous measurement of water flow velocity and solute transport in xylem and phloem of adult plants of Ricinus communis over a daily time course by nuclear magnetic resonance spectrometry

摘要: A new method for simultaneously quantifying rates of flow in xylem and phloem using the FLASH imaging capabilities nuclear magnetic resonance (NMR) spectrometry was applied this study. The has a time resolution up to 4 min (for xylem) used measure velocity flows periods several hours days. For first time, diurnal course measurements velocities apparent volume hypocotyl 40-d-old Ricinus communis L were obtained. Additional data on gas exchange chemical composition leaves, sap assess role leaves as sinks sources phloem. (0.250 ± 0.004 mm s -1 ) constant over full day not notably affected by light/dark cycle. Sucrose loaded into transported at night, owing degradation starch accumulated during day. Concentrations solutes generally less night than but varied little within either or night. In contrast phloem, about 1.6-fold higher light (0.401 dark (0.255 0.003 commensurately. Larger delays observed changes with variation exchange. relative solute transport estimated basis concentrations general, compensated concentration daily However, major (K + , NO 3 - appreciably concentrations. Hence regulation loading systems seems be more important overall process do mass flow. Due behaviour, only regard soluble carbohydrates.