BIOL 1105 Lecture Notes - Lecture 4: Plant Hormone, Cavitation, Tracheid
19 Aug 2016
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Water moves unidirectionally upwards by xylem cells result of a water potential gradient. Carbohydrates move bidirectionally in the plant by phloem. How does water move into xylem: epidermis across root cortex regulated by casparian strip finally in to stele (vascular bundle) Nitrate no3- , phosphate po4 3-, suphate so2 2- dissolved solutes. Transport between cells: movement of solutes across the membrane, solutes of water can also pass through connections called plasmodesmata. Can"t change direction of water movement but can speed up diffusion process. Water potential: potentials are a way to represent free energy for the ability to do work, something with greater potential has more ability to do work, water potential used to predict which way water will move. Measured in units of pressure called megapascals (mpa) Always move from area of higher water potential to an area of lower water potential. Move my diffusion/osmosis across cell walls and membranes.
