LIFESCI 1 Lecture Notes - Lecture 17: Dicotyledon, Root Nodule, Pollen Tube
Document Summary
Phylogeny: green algae most related to terrestrial plants, bryophytes form persistent, photosynthetic gametophytes and small, unbranched sporophytes, angiosperms most diverse. Challenges: gas exchange, water loss, transport (move fluid through out plant, support (without buoyancy, reproduction (without water) 3 main groups: mosses (non-vascular) ferns & lycophytes (seedless vascular plants, seed plants (angiosperms & gymnosperms) Plant cell large central vacuole (water-filled, maintain turgor pressure against cell wall: mitochondria, chloroplast, polysaccharide (cellulose) cell wall -> structure, prevents bursting. Cuticle: tradeoff between gas exchange & water conservation. Light stimulates stomata to open, high level of co2 inside leaf causes it to close (except in cam plants) Guard cells change ion concentration inside them to control osmosis & open/close stomata. Instead of opening stomata during the day, they open stomata at night when it"s less likely to lose water: hang on to the co2 till sun comes out, less efficient, but reduces water loss.
