BISC 101 Lecture 11: (A+ Notes) Water and Sugar Transport in Plants
14 Mar 2016
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= solute (osmotic) potential ( s) + pressure potential ( p) Isotonic solution: solute concentrations are in equilibrium; no net movement. Hypertonic solution: water moves into cell by osmosis, from low to high solute concentrations. Pressure potential: tendency of water to move in response to pressure. Plants have a semi-rigid cell wall, which allows them to not burst like animal cells. Movement of water and solutes into and across roots, and into vascular tissue. Epidermis cortex endodermis pericycle xylem cells. Endodermis: cylindrical layer of cells forming a boundary between cortex and vascular tissue; controls ion uptake (selectivity) Pericycle: cells can become meristematic (produce lateral roots) Stele: vascular tissue in eudicots has xylem forming star shape with phloem between each of the four arms. Transmembrane route: via water: casparian strip: channels. Passive and active transport to move solutes across semi-permeable plasma membranes. Proton pumps: primary role in plants transport process and establishing membrane potentials (electrochemical gradients)
