VASCULAR TISSUE AND TRANSPORT• Plants rely on specialized tissue, called

vascular tissue, to transport water, nutrients, and the products of photosynthesis around the plant.

• The 2 types of vascular tissue are xylem and phloem.

Xylem (zy-lum)What is xylem? Transports water from the roots up

to the rest of the plant in one way flow.What are tracheids? Hollow cell in xylem with thick cell

walls that resist turgor pressure

Capillary Action & Transpiration

• Water rises through the thin tubes by a process called capillary action (cohesion of h20 molecules and adhesion to solid surface). The thinner the tube, the higher the water will rise.

• Plants lose water through their stomata in a process called transpiration. As the leaves lose water, more is drawn up the plant (like liquid through a straw).

• The actions of these two forces, along with root pressure (Root pressure occurs in the xylem when the soil moisture level is high either at night or when transpiration is low during the

day), allows water to be delivered to the entire plant, even to ones that are a hundred feet tall.

Phloem • Vascular tissue that transports sugars (glucose)

produced by photosynthesis to plants in a two-way flow to the roots of the plant.

-dripping sap(sugars) coming from a tree is usually from the phloem

Guard cells: • cells that open and

close the stoma

Stomata: openings in leaf’s surface; when open: • GAS EXCHANGE:

Allows CO2 in & O2

out of leaf • TRANSPIRATION:

Allows excess H2O

out of leaf

GUARD CELL WITH STOMATA

A average size maple tree can transpire 200 liters of water per hour during the summer.

Transpiration is the #1 driving force for pulling water up

stems from roots.

1. Transpiration: loss of excess water from plant leaves

2. Significance:a. Transpiration causes

enough pressure to help pull water (& required nutrients) up stem from roots.

b. As part of the water cycle, trees transpire water back into the atmosphere.

c. Transpiration provides much of the daily rain in rainforest.