Absorption and Transport Chapter 11

Fig. 11-1, p. 164 H2OH2O product of photosynthesis (sucrose) H 2 O vapor H2OH2O mineral ions

Fig. 2-6, p. 18 slight negative charge at this end slight positive charge at this end but the whole molecule has no net charge (+ and – balance each other) Hydrogen bonds in water

Fig. 11-2a, p. 165 water vapor molecules (1) Diffusion

Fig. 11-2b, p. 165 Differentially permeable membrane (water goes through, but not starch) starch solution water net flow (2) Osmosis

Fig. 11-2b, p. 165 (3) Hydrostatic pressure Involves osmosis and the cell wall.

Fig. 2-10, p. 22 Polysaccharides: Cellulose (cellular structure) - monomer is glucose - connected in a straight chain - cellulose molecules bind with each other via hydrogen bonds, resulting in cellulose microfibers Starch (energy storage) - monomer is glucose - connected in a helix

Fig. 3-7 (a-c), p. 36 PROTOPLASTSOLUTION Concentration 0.3 molar (Isotonic) Concentration 0 molar (Hypotonic ) Concentration 0.27 molar Pressure 0.66 megapascals Concentration 0.5 molar (Hypertonic) Concentration 0.3 molar Pressure 0 megapascals Concentration 0.5 molar Pressure 0 megapascals (3) Hydrostatic pressure in cells Turgor pressure is one type of hydrostatic pressure. Turgor pressure is the result of a combination of osmosis and cell wall rigidity.

Fig. 3-7 (d), p. 36 Plasmolyzed cells

Fig. 11-2c, p. 165 force pulling water along side of tube air-water interface capillary tube water tension in water column water molecules connected by hydrogen bonds force pulling the air- water interface straight (4) Capillary forces

(5) Gravity Gravity –Takes force to move water upward –Significant factor in tall trees

Transpiration

Fig. 11-5, p. 168 cuticle is relatively impermeable to H 2 O water-filled xylem in vein cell wall permeated with H 2 O air not saturated water-filled leaf cells substomatal cavity (intercellular space)

Fig. 11-3, p. 167 thin boundary layer; steep gradient; fast diffusion thick boundary layer; gentle gradient; slow diffusion Boundary layer: an unstirred layer of air close to the leaf Bulk air: air outside of the boundary layer Wind stirs up the air close to the leaf and makes the boundary layer thinner. Plants transpire much faster on a windy day than on a still one.

Fig. 11-4, p. 167 sunken stomata spongy parenchyma fibers sunken stomata cuticle stomatal crypts Cross section of a yucca leaf

Flow of Water Into Leaves

Fig. 11-6, p. 168 Capillary forces can convert Water loss into a tension within a tracheid. Before evaporation, there is little tension. After evaporation, there is high tension. Dots: water molecules Short lines: forces of cohesion and adhesion Pits A.B. Tension in the water pulling the tracheid wall inward. Capillary forces pulling water into the tracheid

Fig. 4-11, p. 58 pits in wall one vessel member perforation plate Tracheary elements compared Vessel membersTracheids Vessel members join end to end, but they digest out the end walls forming a tube called a vessel. Tracheids join end to end and along their sides and are connected by bordered pits.

Fig. 11-1, p. 164 H2OH2O product of photosynthesis (sucrose) H 2 O vapor H2OH2O mineral ions

Fig. 11-7, p. 169 plasmodesma symplastic flow apoplastic flow cell wall cytoplasm xylem epidermis cortex stele Casparian strip of endodermis symplast of endodermis root hair Symplastic and apoplastic flow through roots

Control of Water Flow Environmental factors affecting rate of transpiration –Temperature –Relative humidity of bulk air –Wind speed

Control of Water Flow Transpiration –Slow at night –Increases after sun comes up –Peaks middle of day –Decreases to night level over afternoon Rate of transpiration directly related to intensity of light on leaves

Fig. 11-8a, p. 170 plasma membrane proton pump starch malic acid malate– ATP ADP + Pi K+K+ K+K+ H+H+ H+H+ CI    Events leading to the opening of a stoma: The production of malate and the influx of K + and Cl - powered by the electrical and pH gradients produced by the proton pump increase the concentration of osmotically active solutes in the guard cells. As a result, water flows into the cells by osmosis. LIGHT H+H+

Fig. 11-9a, p. 170 cells connected With increased pressure, cell gets longer. Because the outer wall can expand more readily, cell bows outward. reinforced inner wall cellulose microfibrils (radial micellation) How radial micellation and reinforcement of guard cell walls force an expanding cell to bow outward.

Fig. 11-9b, p. 170