What is Translocation (botany)?
'''Translocation''' in [[Vascular plant|vascular plants]] means the movement of organic molecules and some mineral [[ion]]s. Movement of water from the soil to the leaves occurs in [[xylem]] vessels as the result of Transpiration. [[Transpiration]], the [[evaporation]] of water from leaves, causes a pull on the water column due to the forces of cohesion between water molecules formed due to hydrogen bonds which causes the water to move upwards. Organic materials, mainly produced in the leaves, are moved around the plant in the living cells of the [[phloem]] by a process called translocation. Unlike [[xylem]] (which is composed of dead cells), the phloem is composed of still-living cells that transport [[wikt:sap|sap]]. Sap is a water-based solution, rich in [[sugar]]s made by the [[photosynthesis]]. These sugars are transported to non-photosynthetic parts of the plant, such as the roots, or into storage structures, such as [[tuber]]s or bulbs. The 'pressure flow' [[hypothesis]] was proposed by [[Ernst Münch]] in 1930 to explain the mechanism of phloem translocation.<ref> {{cite book|last=Münch E. 1930|title=Die Stoffbewegunen in der Pflanze|publisher=Jena: Gustav Fischer, 234}}</ref> Leaves photosynthesize, making sugars. Water moves into the sugar-laden sieve-tube cells with sugar by [[osmosis]]. This creating pressure that pushes the sap down the sieve tube. When the sugar reaches cells that need it, the cells actively transport sugars out of the sieve-tube elements. During the plant's growth period, usually during the [[Spring (season)|spring]], storage organs such as the [[root]]s are sugar sources, and the plant's many growing areas are sugar sinks. The movement in phloem is multi-directional, whereas, in xylem cells, it is one-directional (upwards). Other molecules like [[amino acid]]s, [[hormone]]s, and even [[messenger RNA]]s are also transported in the phloem through sieve tube elements.<ref name=turgeon2009> {{cite journal |last=Turgeon|first=Robert & Wolf, Shmuel 2009 |title=Phloem transport: cel