Mineral uptake 4322582 215087375 2008-05-26T17:23:10Z 130.15.112.180 In plants, [[mineral uptake]] is the process in which minerals enter the cellular material, typically following the same pathway as [[water]]. The most normal entrance portal for mineral uptake is through plant roots.(Roots, 2005) Some [[mineral ions]] diffuse in-between the [[cell (biology)|cell]]s. In contrast to water, some minerals are actively taken up by plant cells. Mineral [[nutrient]] [[concentration]] in roots may be 10,000 times more than in surrounding soil. During transport throughout a plant, minerals can exit [[xylem]] and enter cells that require them. Mineral ions cross plasma membranes by a chemiosmotic mechanism. Plants absorb minerals in [[ion]]ic form: [[nitrate]] (NO<sub>3</sub><sup>−</sup>), [[phosphate]] (HPO<sub>4</sub><sup>−</sup>) and [[potassium]] [[ions]] (K<sup>+</sup>); all have difficulty crossing a charged [[plasma membrane]]. It has long been known plants expend [[energy]] to actively take up and concentrate mineral ions. Proton pump hydrolyzes ATP to transport H<sup>+</sup> ions out of cell; this sets up an electrochemical gradient that causes positive ions to flow into cells. Negative ions are carried across the plasma membrane in conjunction with H<sup>+</sup> ions as H<sup>+</sup> ions diffuse down their concentration gradient. ==References== *[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/Roots.html Roots and Mineral Uptake (2005)] ==See also== *[[Soil contamination]] {{botany-stub}} {{biochem-stub}} [[Category:Plant physiology]]