Vascular plant anatomy and growth

Biol 121, Fall 2010, Tom Buckley 29 Sep 10

Leaves

leaf

leaflet

petiole

Fig 35.6

leaf: has axillary bud

leaflet: no bud

compound leaf:multiple leafletsone axillary bud

Axil

Leaves

Typical leaf anatomy

cuticle

epidermis

mesophyll

palisade

spongy

vein

bundle sheath

stomata

guard cells

Fig 35.18

adaxial surface

abaxial surface

Leaf anatomy

Karaba et al 2007 PNAS 104:15270

fluorescencelignin: bluechlorophyll: red

image by Gregory Johnson, ASU

leaf scars & bundle traces

Leaf anatomy

tendrils (climbing)

spines

succulent (water storage)

bracts (look like petals)

Modified leaves

rhizomes

stolons

bulbs

tubers

Modified stems

pneumatophores

buttress roots

Modified roots

pneumato- = air

pherein = to carry

Meristems

apical meristems in...

apical buds

axillary buds

root apices

Fig 35.11

year'sgrowth

leaf scars

bud scale scars (from apical buds)

Meristems

Fig 35.11

lateral meristems

vascular cambium

cork cambium

vascular bundle

xylemphloem

fascicularcambium

fasci- = bundle

Primary growth

vascular bundlePrimary growth

X xylem P phloem

vascular bundleinterfascicular cambium

xylemphloem

fascicularcambium

Secondary growth

vascular bundle

vascularcambium

xylemphloem

fascicularcambium

interfascicular cambiumSecondary growth

Year 1

Year 2

Fig 35.20

Fig 35.20

Fig 35.19

XP

Growth ring

{

lateearly woodwood

primary growth

secondary growth(woody plants only)

primary xylem and phloem

secondary xylem and phloem

Dicot stem Monocot stem

no secondary growth

Fig 35.17

(Angiosperms)

Circle danceWhirling dervishes

vascularcambium

vascularcambium

corkcambium

cork

Secondary growth

Fig 35.19

{bark periderm

phloemcork

cambiumcork

Fig 35.23

What is missing?

Root growth

phloem xylem

endodermis

stele (vascular cylinder)

Fig 35.14 stele = star (e.g., 'stellar')

Q: Which term applies to the lateral meristemsindicated by the arrows?

(a) xylem

(b) cambium

(c) cork

(d) cortex

Q: What is the featuresurrounded by the red line?

(a) leaflet

(b) leaf

Q: Which is typically closer to theadaxial surface -- xylem or phloem?

Q: Which is closer to the vascular cambium during winter:earlywood or latewood?

Q: True or False: A leaf is a flattened structure specialisedfor carrying out photosynthesis.

Q: How many years of growth are shown between the arrows?