01:119:116 Lecture Notes - Lecture 10: Ground Tissue, Electromagnetic Absorption By Water, Root System
21 Jul 2019
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Systems are comprised of cells, tissues, organs, systems: hierarchical organization. May help attract pollinators: tissue systems, dermal tissue system. Water absorption at root hairs: ground tissue system. Transports water, sugar, hormones, minerals and structural support. 1. xylem - h2o and minerals are pulled up. Transpiration - water is cohesive, each water drop sticks and as it comes in as the plant grows it creates a chain of water droplets. Also stick to the side of the xylem tubes so it sticks on even if the water stops. Cohesion-tension hypothesis - sun rises -> photosynthesis occurs -> stomata open -> transcription. Cohesion - h2o sticks to itself with h-bonds. Adhesion - h2o sticks to other things with h-bonds. Allows unbroken water column to form and adhere to xylem walls. 2. phloem - right next to the xylem flows everywhere) Translocation of sugars - moves source -> sink (fruit or root) (somewhere sugar can"t be made but needs sugar)
