Lab #7

Roots, Stems and Leaves

Chloroplasts

Plastids

Amyloplasts – from garden bean

chromoplasts – from red pepper

Parenchyma tissue

spongy

palisade

Collenchyma

collenchyma

sclerenchyma

collenchyma

parenchyma

Sclerenchyma

Epidermis & Guard cells

Epidermal structures

Guards cells + Stoma

Trichome and leaf cross section

protoxylem

metaxylem

VE

Tracheids

metaxylem

Xylem

metaxylem

protoxylem phloem

WATER-CONDUCTING CELLS OF THE XYLEM

Tracheids

Pits

Tracheidswith circular-bordered pitsin their primary walls TRACHEIDS

from Biology 311 site Alison Roberts (aroberts@uri.edu) © 1998-2012 AWR

Tracheids with annular thickenings

from Biology 311 site Alison Roberts (aroberts@uri.edu) © 1998-2012 AWR

tracheids

perforation plates in the side walls of a vessel element

vessel elementswith perforation plates

VESSEL ELEMENTS

tracheidsvessel elements

alignedperforationplates

Tracheids vs. Vessel

Elements

tracheidsvessel elements

vessel elements

tracheids

most angiosperm xylem containsvessel elements

Vessel Elements

VE

VE

VEVE

protoxylem

metaxylem

Phloem

sieve elements

Phloem

Phloem

http://www.sbs.utexas.edu/mauseth/weblab/webchap8phloem/chapter_8.htm

companion cell

companion cell

companion cell

companion cell

companion cell

sieve tubemembers

sieve plate

Phloem

sieve plate

http://www.sbs.utexas.edu/mauseth/weblab/webchap8phloem/chapter_8.htm

Leaf tissues

vascular bundles

Mesophyll – Palisade and Spongy

spongy

palisade

epidermis

epidermis

Pine needles

Apical meristem

apical meristem

axillary bud

developingvascular tissue

developing leaf primordia subapical

meristem

apical meristem

Root Meristems

RootApicalmeristem

Root cap

RootApicalmeristem

Root cap

Monocot Stems

Monocot stemsepidermis

parenchyma

cortex

Monocot Stem Vascular Bundle

xylem

sclerenchyma is called a bundle sheath inmonocot leaf vascular bundles

sclerenchyma

phloem

metaphloem

protoxylem

metaxylem

No vascular cambium – no secondary growth!

Monocot Leaf

Monocot leaves

monocot leafvein

monocot leafveins

Monocot Roots

Phloem

Xylem

Pericycle

Core ofparenchymacells

Endodermis

Monocot Root

http://www2.mcdaniel.edu/Biology/botf99/rootuse/monovsdi.htm

pith

xylem(vessel element& tracheids)

phloem

pericycle

pith

Monocot root

xylem(vessel element& tracheids)

phloem

pericycle

endodermis

pith

Dicot Stems

MedullaryRays

Dicot stems

from Biology 311 site Alison Roberts (aroberts@uri.edu) © 1998-2012 AWR

Helianthus (sunflower)

phloem

metaxylem

protoxylem

vascularcambium

Trifolium (clover)

epidermis

cortex

pith

Dicot Stem

interfasicularcambium

fasicularcambium

sclerenchyma

xylem

pith

phloem

Dicot Stem Vascular Bundle

sclerenchyma

tracheids

region ofprotoxylem

region ofmetaxylem vessel

elements

Monocot vs. Dicot Stem

DICOTMONOCOT

Dicot vs. Monocot Vascular Bundles

from Biology 311 site Alison Roberts (aroberts@uri.edu) © 1998-2012 AWR

DICOT

sclerenchyma

tracheid

phloem

vascularcambium

protoxylemmetaxylem

VE VEVE

sclerenchyma

MONOCOT

Sclerenchyma

tracheid

VE

VE

Dicot Leaves

collenchyma

Dicot leaf veins

Dicot Leaf

Stained cross-section through the leaf of lilac: 1 upper epidermis, 2 palisade parenchyma, 3 spongy parenchyma, 4 air cavity, 5 lower epidermis, 6 stomata, 7 trichome, 8 major vein, 9 xylem, 10 phloem, 11 supporting tissue (sclerenchyma)http://www.vcbio.science.ru.nl/en/virtuallessons/leaf/mesomorph/

Key

DermalGroundVascular

Epidermis

Cortex

Vascular cylinder

Transverse section of a typical root. In the roots of typical gymnosperms and eudicots, as well as some monocots, the stele is a vascular cylinder consisting of a lobed core of xylem with phloem between the lobes.

100 µm

Endodermis

Core ofparenchymacells

Pericycle

Xylem

Phloem

Endodermis

Pericycle

Xylem

Phloem

50 µm

Dicot Roots

endodermis

Dicot Roots

Dicot Root

metaxylem

vascular cylinder = stele

from Biology 311 site Alison Roberts (aroberts@uri.edu) © 1998-2012 AWR

phloem

pericycle

endodermis

VE VE

VE

Dicot vs. Monocot Root

Dicot Lateral Root

Secondary growth

Secondary growth

Secondary growth

Secondary growth:Stems vs. Roots

tracheids

xylem rayvessel element

perforationplate

perforation plate: the end of a vessel element w

Ash wood

from Biology 311 site Alison Roberts (aroberts@uri.edu) © 1998-2012 AWR

perforationplate

http://www.sbs.utexas.edu/mauseth/weblab/webchap7xylem/chapter_7.htm

Oak

Vessel element

http://www.sbs.utexas.edu/mauseth/weblab/webchap7xylem/chapter_7.htm

tracheids

vessel elements

from Biology 311 site Alison Roberts (aroberts@uri.edu) © 1998-2012 AWR

3 yr Tilia stem (Basswood)

pits

perforationplates

from Biology 311 site Alison Roberts (aroberts@uri.edu) © 1998-2012 AWR

3 yr Tilia stem (Basswood)

3 yr Tilia stem (Basswood)

secondary xylem(tracheids &vessel elements)

secondary xylem(tracheids &vessel elements)

secondary xylem(tracheids &vessel elements)

vascularcambium

secondaryphloem

cork

corkcambium

cork + cork cambium = Peridermvascular cambium to cork = Bark

annual ring

annual ring

annual ring

axial system of wood(tracheids & vessel elements)

small arrows = vesselelements

Ilex opaca (American holly, a dicot or hardwood)

NOT A CONIFER LIKE A PINE!!(has vessel elements)

American Holly

http://www.sbs.utexas.edu/mauseth/weblab/webchap15wood/chapter_15.htm

White pine

http://www.sbs.utexas.edu/mauseth/weblab/webchap15wood/chapter_15.htm

axial system of wood(tracheids)

tracheids of springwood

tracheids of summerwood

annual ring

Soft wood = no vesselelements!!

White Pine

tracheids of springwood

tracheids of summerwood

circular bordered pit between two tracheids

http://www.sbs.utexas.edu/mauseth/weblab/webchap15wood/chapter_15.htm

White Pine

tracheids of a xylem ray

http://www.sbs.utexas.edu/mauseth/weblab/webchap15wood/chapter_15.htm

Cork Cambium

cork cambium

cork

from Biology 311 site Alison Roberts (aroberts@uri.edu) © 1998-2012 AWR

lenticel

Lenticel

from Biology 311 site Alison Roberts (aroberts@uri.edu) © 1998-2012 AWR