9 3 WaterSugar Transport in Plants p 331

9. 3 Water/Sugar Transport in Plants p. 331 – 340 Water transport in xylem vessels ü Sugar transport in phloem vessels ü Uptake of water in roots ü

NO PUMP!!!! So what happens? Properties of H 2 O that aid in water transport Root pressure Transpiration

Plant Vascular System Interconnected tubes Extend throughout plant Made of Xylem and Phloem = specialized TISSUES that transport water, minerals and sugars throughout the plant

Xylem Transports water and dissolved minerals from soil to leaves Start out as living cells then DIE Only cell walls remain Cells linked end to make long tubes called XYLEM VESSELS

Xylem Vessels (ls)

Xylem Vessels (xs)

Several cell types: tracheids and vessel elements

Phloem Transport sugar (sap) from leaves to rest of plant

Phloem Vessels Live cells Arranged end to end in long connecting tubes

Several types of cells Sieve tubes and companion cells

How does water move through the plant without a pump? ?

H 20 absorption in roots Root hairs increase surface area for osmosis

1. Root Pressure Soil outside root is hypotonic to root cell so water enters cell by osmosis

2. Cohesion of Water Molecules Water sticks to other water molecules and forms a long chain of water molecules and pull eachother along

3. Adhesion of Water Molecules Water sticks to inside walls of xylem

4. Transpiration Pressure Water flows out of stomata in leaves by diffusion The air spaces created are filled in by new water molecules (adhesion and cohesion) This pulls the whole column of water up the xylem

How do sugars move in phloem? Pressure Flow Theory

How do sugars move in phloem? Sugars made in palisade layer (spongy mesophyll) are actively transported from leaf cells to the phloem system

Pumping of sugars into the phloem makes the phloem hypertonic (lower concentration of water) to the cells around it

water moves into phloem from the surrounding cells by osmosis

Water entering the phloem system creates pressure that moves sugar and water down phloem to rest of plant and roots

http: //www. pearsoned. ca/school/scien ce 11/biology 11/sugartransport. html