EARTHSS 164 Lecture Notes - Lecture 17: Depletion Region, Nitrogen Fixation, Mass Flow

• School: UC-Irvine
• Department: Earth System Science
• Course: EARTHSS 164
• Professor: Professor Allison

Document Summary

Roots take up nutrients across cell membrane by active transport. Allows nutrients to move towards the plant root (down concentration gradient) Ions differs in mobility and accessibility by roots. Ammonium and phosphate have lower potential to move through soil. Hard for the root to extract nutrients from soil. Important for macronutrients at high soil concentrations. Roots encounter nutrients by growing unexplored soil. Slight preference for ammonium (already reduced form) Can"t take up nutrients that aren"t there present in soil. Increase the roots:shoot ratio and root length to increase uptake surface area. Root hairs support uptake by adding surface area. Produce exudates (organic acids) to dissolve rock. Helps plants acquire nutrients from soil hyphae can grow. Plant provide carbon to fungus in exchange for nutrients. Saprotrophs obtain c from soil organic matter. Fossil plants have mycorrhizae, helped plants colonize land. Form arbuscules and vesicles inside plant root. One fungue, multiple hosts or one host, multiple fungi.