Exam #2 M 3/8 in classQ&A Fri. 3/5 from 4-6pm in WRW 102

Plants grow and reproduce, as well as, respond to the environment.

Plants grow and reproduce, respond to the environment… today- transport

Types of Plant Cells:defined by function and cell wall

Fig 6.9

Plant cell walls are mostly made of cellulose

Cellulose is made of glucose

Fig 5.7

Fig 5.8

Cellulose is made of

glucose

Fig 5.9

Only a few prokaryotes and fungi can digest cellulose

Cell walls contain cellulose, pectins, proteins...

Fig 35.10

60 m

Parenchyma cells- most common cells; primary cell walls

Fig 35.17Parenchyma in a stem

Fig35.10

Collenchyma cells- unevenly thickened cell walls; flexible support

80 m

Collenchyma in a leaf

Sclerenchyma cells- Thickened secondary walls (inside primary wall); with lignin; rigid

5 m

25 m

Fig 35.10

Fig 35.10

Water conducting cells of Xylem:

vesselsand

tracheids(types of sclerenchyma)

100 m

Sugar conducting cells of Phloem: sieve-tubes and companion cells

15 m

30 m

Fig 35.10

Fig 36.2

Plants transport water in xylem, sugar in phloem, plus minerals and hormones…

Fig 36.2

Water travels from ground out through stomata via xylem

Fig 36.2

The exit of water through stomata is accompanied by gas exchange

Fig 36.2

Sunlight powers photosynthesis and these sugars are transported via phloem

Fig 36.20

Phloem transport is from source to sink.

Fig 36.20

Sugar is loaded at sources and unloaded at sinks...

consuming ATP

source:leaf

sink:root, flower, emerging leaf etc…

Source and sink locations vary...

The direction of Phloem transport is versatile.

Fig 36.10

Much of plant support comes from turgor pressure.

CB 36.15

Water moves from the ground through roots into the shoot and out stomata in the leaves.

Fig 35.13

In roots the vascular bundle is in the center

Fig 36.11

Plant cell to cell transport can occur by two pathways: symplastic and apoplastic

plasmodesmata

Fig 36.12

The casparian strip of the endodermis keeps water from entering the xylem via a purely apoplastic route.

What moves the water through the xylem?

Stomata control entry of CO2 and exit of H2O from plant leaves

Stomata

Fig 36.14

Stomata on the underside of a leaf

Fig 36.17

Guard cell opening is regulated by turgor

Fig 36.15

What moves the water through the xylem?Transpiration, Adhesion, Cohesion, andTension

water transport limits plant growth

xylem

phloem

More xylem is needed for more water transport: secondary growth

xylem

phloem

Xylem is tough, and full of lignin- inhibits the ability to use plants to produce biofuels

Exam #2 M 3/8 in classQ&A Fri. 3/5 from 4-6pm in WRW 102