Plant Transport Systems

Plant Transport Systems

Honors BiologyChapter 7p. 185-191

Honors BiologyChapter 7p. 185-191

Plant Life on LandPlant Life on Land• 430 million years ago plants

adapted to life on land. • First plant adaptations to land were

a thick waxy cuticle to prevent water loss and protection for gametes and embryos.

• Vascular and Nonvascular Plants– Vascular plants- have vessels to

transfer water and nutrients– Non Vascular Plants- mosses

bryophytes, etc. (moist environments)

• 430 million years ago plants adapted to life on land.

• First plant adaptations to land were a thick waxy cuticle to prevent water loss and protection for gametes and embryos.

• Vascular and Nonvascular Plants– Vascular plants- have vessels to

transfer water and nutrients– Non Vascular Plants- mosses

bryophytes, etc. (moist environments)

Vascular PlantsVascular Plants• Vascular Plants have specialized

leaves and stems to get CO2 and light from above ground.

• Vascular Plants have underground root system to absorb water and minerals from ground. – Some roots have root hairs to increase

water absorption.

• Lignin- hard material in the cell walls of vascular plants that allows plants and trees to stand upright.

• Vascular Plants have specialized leaves and stems to get CO2 and light from above ground.

• Vascular Plants have underground root system to absorb water and minerals from ground. – Some roots have root hairs to increase

water absorption.

• Lignin- hard material in the cell walls of vascular plants that allows plants and trees to stand upright.

LigninLignin

Xylem Xylem • Carry water and nutrients from

roots to rest of plant.• Tracheids- pointed ends and thick

walls with pits that connect them to cells.

• Vessel elements- wider, shorter, thinner walled, and less tapered

• Carry water and nutrients from roots to rest of plant.

• Tracheids- pointed ends and thick walls with pits that connect them to cells.

• Vessel elements- wider, shorter, thinner walled, and less tapered

Cohesion-Tension TheoryCohesion-Tension Theory• Water moves up the xylem of a vascular

plant due to root pressure, transpiration, and the adhesive and cohesive properties of water.

• Pressure exerted by the roots forces water up the xylem.

• Cohesion- the property of water molecules to stick together (water molecules hydrogen bond to other water molecules)

• Adhesion- the property of water to stick to other charged molecules.

• Water moves up the xylem of a vascular plant due to root pressure, transpiration, and the adhesive and cohesive properties of water.

• Pressure exerted by the roots forces water up the xylem.

• Cohesion- the property of water molecules to stick together (water molecules hydrogen bond to other water molecules)

• Adhesion- the property of water to stick to other charged molecules.

Cohesion-Tension TheoryCohesion-Tension Theory• Due to cohesion of water and the

adhesion of water to charged groups on the surface of the tracheid and vessel cells, water will rise in the xylem through capillary action.

• Transpiration- Leaves lose water by evaporation through their leaves

• Transpiration cause an area of tension(low pressure)

• As water molecules transpire through the stomates of leaves the cohesion of water will pull on other water molecules that will pull water up the xylem of the entire plant.

• Due to cohesion of water and the adhesion of water to charged groups on the surface of the tracheid and vessel cells, water will rise in the xylem through capillary action.

• Transpiration- Leaves lose water by evaporation through their leaves

• Transpiration cause an area of tension(low pressure)

• As water molecules transpire through the stomates of leaves the cohesion of water will pull on other water molecules that will pull water up the xylem of the entire plant.

Cohesion-Tension Theory Animations

Cohesion-Tension Theory Animations

• http://bcs.whfreeman.com/thelifewire/content/chp36/36020.html

• http://academic.kellogg.cc.mi.us/herbrandsonc/bio111/animations/0031.swf

• http://bcs.whfreeman.com/thelifewire/content/chp36/36020.html

• http://academic.kellogg.cc.mi.us/herbrandsonc/bio111/animations/0031.swf

PhloemPhloem

• Sugar and other organic materials must move to all parts of the plant.

• Phloem- living cells that transport sugars and amino acids to different parts of the plant.

• These substance can move up or down the plant through the phloem.

• Holes called sieve tubes transport materials between phloem cells.

• Sugar and other organic materials must move to all parts of the plant.

• Phloem- living cells that transport sugars and amino acids to different parts of the plant.

• These substance can move up or down the plant through the phloem.

• Holes called sieve tubes transport materials between phloem cells.

PhloemPhloem

Pressure Flow Hypothesis Pressure Flow Hypothesis

• Materials from phloem move from source to sink cells.– Source cells can be- cotyledons and

endosperm during germination, leaves during spring and summer, storage roots during spring.

– Sink cells are any cell that uses water and sugars, food storage areas, and growing leaf buds, root tips, flowers, fruits, and seeds.

• Materials from phloem move from source to sink cells.– Source cells can be- cotyledons and

endosperm during germination, leaves during spring and summer, storage roots during spring.

– Sink cells are any cell that uses water and sugars, food storage areas, and growing leaf buds, root tips, flowers, fruits, and seeds.

Pressure Flow HypothesisPressure Flow Hypothesis• Sucrose is actively transported into a

source cell. • Water will flow into the source cell by

osmosis which increases the turgor pressure.

• This increased pressure will push sucrose molecules through the sieve tubes to other phloem cells towards sink cells.

• At the sink cells, sucrose and amino acids will be actively transported to other cells to be used or stored

• Water will flow out of the sink cells by osmosis

• Sucrose is actively transported into a source cell.

• Water will flow into the source cell by osmosis which increases the turgor pressure.

• This increased pressure will push sucrose molecules through the sieve tubes to other phloem cells towards sink cells.

• At the sink cells, sucrose and amino acids will be actively transported to other cells to be used or stored

• Water will flow out of the sink cells by osmosis

Pressure-Flow TheoryPressure-Flow Theory

• http://bcs.whfreeman.com/thelifewire/content/chp36/36020.html

• http://bcs.whfreeman.com/thelifewire/content/chp36/36020.html

• http://bcs.whfreeman.com/thelifewire/content/chp36/36020.html

• http://bcs.whfreeman.com/thelifewire/content/chp36/36020.html