This page explains that phloem transports organic substances in plants, aided by companion cells, with rates up to 110 μm per second. Girdling removes phloem, starving roots. The pressure-flow hypothe...This page explains that phloem transports organic substances in plants, aided by companion cells, with rates up to 110 μm per second. Girdling removes phloem, starving roots. The pressure-flow hypothesis details nutrient translocation aided by osmotic pressure differences and sugar accumulation in leaves, creating turgor pressure. It also mentions that mRNAs can be transferred through phloem, affecting phenotype in grafted plants.
