plant tissues

1. Plant Tissues: OverviewPlant Tissues: Overview
Meristems, Simple Tissues, &Meristems, Simple Tissues, &
Complex TissuesComplex Tissues
Many of the figures found in this presentation are from the internet siteMany of the figures found in this presentation are from the internet site
http://botit.botany.wisc.edu/images/130/http://botit.botany.wisc.edu/images/130/ and a CD entitled “Plant Anatomy” byand a CD entitled “Plant Anatomy” by
Richard Crang & Andrey Vassilyev published by McGraw Hill.Richard Crang & Andrey Vassilyev published by McGraw Hill.

2. Meristematic tissues – localizedMeristematic tissues – localized
regions of cell divisionregions of cell division
 Apical MeristemsApical Meristems
 Primary or Transitional MeristemPrimary or Transitional Meristem  Primary growthPrimary growth
 ProtodermProtoderm  gives rise to epidermisgives rise to epidermis
 Ground meristemGround meristem  gives rise to ground tissuegives rise to ground tissue

ProcambiumProcambium  gives rise to 1gives rise to 1
oo
vascular tissuevascular tissue
 Lateral MeristemsLateral Meristems
 Vascular cambiumVascular cambium  22
oo
vascular tissuevascular tissue
 Cork cambium or phellogenCork cambium or phellogen  peridermperiderm
 Intercalary Meristems (found in the nodes of grasses)Intercalary Meristems (found in the nodes of grasses)

3. Illustration from: http://biology.nebrwesleyan.edu/benham/mitosis/
1. Interphase
2. Prophase
3. Metaphase
4. Anaphase
5. Telophase
6. Cytokinesis
Cell Division: Mitosis (nuclear division)
+ Cytokinesis (cytoplasmic division)

4. Shoot Apical MeristemShoot Apical Meristem

5. Root Apical MeristemRoot Apical Meristem
1. Root cap
initials
2. Protoderm
3. Ground
meristem
4. Procambium
5. Root cap

6. Lateral Meristems – secondaryLateral Meristems – secondary
growth in woody plantsgrowth in woody plants
Basswood – root in cross section
Basswood – stem in cross
section; 1, 2, 3 year old stems

7. Intercalary Meristems in GrassesIntercalary Meristems in Grasses
http://www2.mcdaniel.edu/Biology/wildameric
a/grasslands/graslandoutline.html

8. Simple Tissues – consisting of oneSimple Tissues – consisting of one
cell typecell type
 Parenchyma –Parenchyma – thin walled & alive at maturity;thin walled & alive at maturity;
often multifaceted.often multifaceted.
 Collenchyma –Collenchyma – thick walled & alive at maturitythick walled & alive at maturity
 Sclerenchyma –Sclerenchyma – thick walled and dead at maturitythick walled and dead at maturity
 Sclerids or stone cells –Sclerids or stone cells – cells as long as they are widecells as long as they are wide
 Fibers –Fibers – cells longer than they are widecells longer than they are wide
 Epidermis – alive at maturityEpidermis – alive at maturity
 Trichomes – “pubescence” or hairs on epidermisTrichomes – “pubescence” or hairs on epidermis
 Root Hairs – tubular extensions of epidermal cellsRoot Hairs – tubular extensions of epidermal cells

9. ParenchymaParenchyma

10. CollenchymaCollenchyma

11. SclerenchymaSclerenchyma
Right-hand illustration modified from: Weier,
Stocking & Barbour, 1974, Botany: An
Introduction to Plant Biology, 5th Ed.
SCLERIDS FIBERS

12. Epidermis –Epidermis – stoma, trichomes, & root hairsstoma, trichomes, & root hairs
http://www.ucd.ie/botany/Steer/hair/roothairs.html

13. Complex TissueComplex Tissue
 Xylem – water conducting tissue;Xylem – water conducting tissue; parenchyma, fibers,parenchyma, fibers,
vessels and/or tracheids, and ray cells.vessels and/or tracheids, and ray cells.
 Phloem food conducting tissue;Phloem food conducting tissue; sieve-tube memberssieve-tube members
(no nucleus at maturity, cytoplasm present),(no nucleus at maturity, cytoplasm present),
companion cells, fibers, parenchyma, and ray cells.companion cells, fibers, parenchyma, and ray cells.
In flowering plants, sieve-tube members andIn flowering plants, sieve-tube members and
companion cells arise from the same mother cell.companion cells arise from the same mother cell.
 Periderm – protective covering;Periderm – protective covering; composed of corkcomposed of cork
and parenchyma.and parenchyma.
 Secretory structuresSecretory structures –– responsible for making latex,responsible for making latex,
resins, nectar and other substances produced andresins, nectar and other substances produced and
stored in channels inside the plant body.stored in channels inside the plant body.

14. XylemXylem

15. PhloemPhloem

16. Vascular Bundles with xylem & phloemVascular Bundles with xylem & phloem
Maize or Corn – vein in cross
section
Alfalfa – vein in cross section

17. Periderm – cork & parenchymaPeriderm – cork & parenchyma
TWIG WITH LENTICELS

18. Secretory StructuresSecretory Structures
 nectar (flowers) from nectariesnectar (flowers) from nectaries
 oils (peanuts, oranges, citrus) from accumulation ofoils (peanuts, oranges, citrus) from accumulation of
glands and elaioplasts.glands and elaioplasts.
 resins (conifers) from resin canalsresins (conifers) from resin canals
 lacticifers (e.g., latex - milkweed, rubber plants,lacticifers (e.g., latex - milkweed, rubber plants,
opium poppy)opium poppy)
 hydathodes (openings for secretion of water)hydathodes (openings for secretion of water)
 digestive glands of carnivorous plants (enzymes)digestive glands of carnivorous plants (enzymes)
 salt glands that shed salt (especial in plants adapted tosalt glands that shed salt (especial in plants adapted to
environments laden with salt).environments laden with salt).