in angiosperms 10/29/08 Roots take up water via roots Large surface area is needed Roots branch and have root hairs Cortex structure also helps uptake

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1 in angiosperms A. Root System Roots take up water via roots Large surface area is needed Roots branch and have root hairs Cortex structure also helps uptake 1

B. Minerals Nitrogen (NO 3-,NH 4+ ) Potassium (K + ) Phosphorus (PO 4 3- ) Calcium (Ca 2+ ) C.

Diffusion When a mineral is more concentrated in the soil, it moves by diffusion into the root. 2.

hyphae grow out into the soil and absorb minerals, & transport them to the plant roots Plant

2 B. Minerals Nitrogen (NO 3-,NH 4+ ) Potassium (K + ) Phosphorus (PO 4 3- ) Calcium (Ca 2+ ) C. Three uptake methods (Diffusion, Fungal hyphae, Mass flow) C. Uptake Methods 1. Diffusion When a mineral is more concentrated in the soil, it moves by diffusion into the root. 2. Fungal Hyphae Mutualistic relationship between fungus growing in the roots, and the plant Fungus hyphae grow out into the soil and absorb minerals, & transport them to the plant roots Plant delivers sugar to the fungus 3. Mass flow of water The plant takes up large volumes of water, which has minerals in it. 2

D. Active Transport 1 The concentration of minerals in soil is much lower than in the plant 2 Mitochondria in the roots make ATP through aerobic

ions can diffuse in Negative ions can follow H + as it diffuses back in. A. No skeleton for support B.

Herbaceous plants depend upon turgor for support 1. as vacuoles take up water, cells swell, stretching to the limit 2.

3 D. Active Transport 1 The concentration of minerals in soil is much lower than in the plant 2 Mitochondria in the roots make ATP through aerobic respiration 3 Proton pumps in the cell membrane of the root hairs pump OUT H + 4 So the soil is more positive, inside the root is more negative Positive ions can diffuse in Negative ions can follow H + as it diffuses back in. A. No skeleton for support B. Some cells have thickened cellulose walls to strengthen plant C. Trees & shrubs have woody stems Xylem vessels have some supporting tissue - lignin D. Herbaceous plants depend upon turgor for support 1. as vacuoles take up water, cells swell, stretching to the limit 2. vacuole will still have a lower water potential than surrounding cells, so it will continue to draw water. 3. force of cell wall will force out water at the same rate. 4. all these cells, packed with water and stacked on each other, provide GOOD support. 3

Transpiration Stream Flow of water from the roots through the stems to the leaves of plants. D. The Process 1. Evaporation from leaves (spongy mesophyll) 2.

4 A. Definition the loss of water vapor from the leaves and stems of plants B. The need Leaves make sugar, water and mineral are absorbed in roots It is necessary to move substances from one place to another C. Transpiration Stream Flow of water from the roots through the stems to the leaves of plants. D. The Process 1. Evaporation from leaves (spongy mesophyll) 2. Water from xylem vessels replaces it Water is PULLED out of xylem vessels and through pores in the spongy mesophyll cell walls by capillary action, this is the transpiration pull 3. Transpiration pull is transmitted down long columns of water in the xylem vessels to the roots Depends on cohesion of water molecules due to hydrogen bonding. 4

E. Xylem Vessel Structure 1 Mature xylem are dead water flows passively 2 No

them hard to resist inward pressures 4 Lumen of xylem vessel sap filled As

Pores in outer cell wall conduct water out of xylem vessels, into cell walls of

5 E. Xylem Vessel Structure 1 Mature xylem are dead water flows passively 2 No plasma membrane water can move freely in & out 3 Helical thickenings Lignin makes them hard to resist inward pressures 4 Lumen of xylem vessel sap filled As cytoplasm and nuclei break down 5 End walls break down forms a continuous tube 6 Pores in outer cell wall conduct water out of xylem vessels, into cell walls of adjacent leaf cells. F. Guard Cells Open & close stomata to regulate water loss transpiration 5

When the abscisic acid reaches the leaves, it changes the

Guard cells lose water through osmosis and become flaccid (limp) 5.

When turgor is restored, guard cells become stiff and stomata open. G.

Light Guard cells open to let in CO2 for photosynthesis This increases

6 F. Guard Cells 1. Roots don t have enough water to replace the water lost in transpiration 2. They release the plant hormone, abscisic acid into the xylem vessels 3. When the abscisic acid reaches the leaves, it changes the concentration of dissolved particles in the guard cells 4. Guard cells lose water through osmosis and become flaccid (limp) 5. The guard cells sag together, and close the stomata 6. When turgor is restored, guard cells become stiff and stomata open. G. Abiotic Factors effecting transpiration 1. Light Guard cells open to let in CO2 for photosynthesis This increases water loss 2. Temperature The rate of evaporation doubles for every 10ºC increase in temperature 3. Wind Takes water vapor away from the leaf, maintaining the concentration gradient, so more water leaves the leaf 4. Humidity Evaporation is higher in dry air 6

pore 4. Deep roots to reach deep water 5.

rain H. Xerophyte Adaptations 6. Low growth 7.

7 H. Xerophyte Adaptations 1. Reduced leaves Cactus spines, pine needles 2. Thick waxy cuticle 3. Stomata in pits surrounded by hairs Reduces air flow past pore 4. Deep roots to reach deep water 5. Wide-spreading network of shallow roots to absorb water after rain H. Xerophyte Adaptations 6. Low growth 7. Reduced number of stomata 8. Water storage in thick stems 9. Life cycle during the wet season 10. Vertical stems so photosynthesis occurs at sunrise & sunset, not noon Sedum Saguaro cactus 7

In daylight, CO 2 released It is used in photosynthesis A.

Source = leaves and other parts that do photosynthesis, also storage organs when food is taken out of storage 2.

8 H. Xerophyte Adaptations 11. CAM physiology Stomata closed during day Stomata open at night CO 2 taken in and stored in malate (malic acid) In daylight, CO 2 released It is used in photosynthesis A. Translocation: the movement of substances (sugars and amino acids) from source to sink in the phloem. 1. Source = leaves and other parts that do photosynthesis, also storage organs when food is taken out of storage 2. Sink = place where food is used (a fruit, seeds) or stored (roots or other storage organs) B. Phloem sap: Sugars, amino acids and other organic compounds produced in photosynthesis C. Energy is used by phloem cells for active transport to move the food. 8

PLANT SCIENCE. 9.2 Transport in Angiospermophytes

PLANT SCIENCE. 9.2 Transport in Angiospermophytes PLANT SCIENCE 9.2 Transport in Angiospermophytes Support of terrestrial plants Support of terrestrial plants comes through: Thickened cellulose in cell walls Turgor pressure of cells Lignified xylem Xylem