Bio 1150 1st Edition Lecture 23Current LectureTopic Discussed: Resource Acquisition & Transport in Vascular PlantsResource acquisition and transport in vascular plantsOverview of transport in a plant- Gas exchange- water vapor, carbon dioxide and oxygen- Photosynthesis- lightShoots are optimized to capture light and reduce water loss- tropical plants- large leaves - dry environments - small leaves - Alternate phyllotaxy limits overlapping of leaves in lower light environment- Opposite phyllotaxy may be advantageous in high light environments- “phyll”= leaf; “taxy”=arrangementLeaf orientation optimizes light conditions- Leaves can angle themselves for optimal light- Phototropism-growth towards windowsRoots are optimized to absorb and anchor- Taproot systems- anchor tall plantsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- More branching in areas of high resources- Less branching in roots of self- Mycorrhizae enhance root absorption- Hyphae- roots of the fungiSubstances move through the apoplast and/or the symplast- Apoplastic-route outside cell membrane- Symplastic- cell to cell, with in the cell membrane, linked by plasmodesmata- Transmembrane- through membranesMovement of substances across cell membranes- Proton pumps -set up chemiosmotic gradient, which is then used for co-transporto Uses ATP hydrolysis to put protons outside cello Creates charge gradient, lowers pHo Puts uncharged things in cell (like sucrose)o Makes protons want to come inside cell- Ion channels- open in response to chemicals, pressure or voltageWater moves by osmosis- Water potential gradient drives direction of water movement- Water moves from areas of higher water potential to areas of lower water potential- Water potential- (ψ) Mpa=MegaPascals- Water potential is determined by solute concentration and physical pressureo Ψ = ψs + ψp- The addition of solutes decreases water potential- Adding positive pressure increases water potentialTurgor pressure and wilting- Turgid-vacuole full of water, membrane pushes against cell wall, cell wall pushes back- Flaccid-wilting, loses water, loses shape- Plasmolysis-shrinkingBulk flow- For long distance transport- is movement of liquid in response to a pressure gradient- is independent of solute concentrationMoving water and minerals into the xylem- Water and minerals in the xylem move by bulk flow driven by transpiration- Apoplastic and symplastic; transmembrane= exchange from previous two- casperian strip-impenetrable- xylem cells- dead, no membranes, turns
View Full Document
Unlocking...