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 site Many of the figures found in this presentation are from the internet site http://botit.botany.wisc.edu/images/130/ and a CD entitled “Plant Anatomy” by http://botit.botany.wisc.edu/images/130/ and a CD entitled “Plant Anatomy” by

Richard Crang & Andrey Vassilyev published by McGraw Hill. Richard Crang & Andrey Vassilyev published by McGraw Hill.

Meristematic tissues – localized Meristematic tissues – localized regions of cell divisionregions of cell division

Apical MeristemsApical Meristems Primary or Transitional Meristem Primary or Transitional Meristem Primary growth Primary growth

Protoderm Protoderm gives rise to epidermis gives rise to epidermis Ground meristem Ground meristem gives rise to ground tissue gives rise to ground tissue Procambium Procambium gives rise to 1 gives rise to 1oo

vascular tissue vascular tissue Lateral MeristemsLateral Meristems

Vascular cambium Vascular cambium 2 2oo vascular tissue vascular tissue

Cork cambium or phellogen Cork cambium or phellogen periderm periderm Intercalary Meristems (found in the nodes of grasses)Intercalary Meristems (found in the nodes of grasses)

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)

Shoot Apical MeristemShoot Apical Meristem

Root Apical MeristemRoot Apical Meristem

1. Root cap initials

2. Protoderm3. Ground

meristem4. Procambium5. Root cap

Lateral Meristems – secondary Lateral Meristems – secondary growth in woody plantsgrowth in woody plants

Basswood – root in cross sectionBasswood – stem in cross section; 1, 2, 3 year old stems

Intercalary Meristems in GrassesIntercalary Meristems in Grasses

http://www2.mcdaniel.edu/Biology/wildamerica/grasslands/graslandoutline.html

Simple Tissues – consisting of one Simple 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

ParenchymaParenchyma

CollenchymaCollenchyma

SclerenchymaSclerenchyma

Right-hand illustration modified from: Weier, Stocking & Barbour, 1974, Botany: An

Introduction to Plant Biology, 5th Ed.

SCLERIDS FIBERS

Epidermis – Epidermis – stoma, trichomes, & root hairsstoma, trichomes, & root hairs

http://www.ucd.ie/botany/Steer/hair/roothairs.html

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 members sieve-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 and In 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 cork composed of cork and parenchyma.and parenchyma.

Secretory structuresSecretory structures – – responsible for making latex, responsible for making latex, resins, nectar and other substances produced and resins, nectar and other substances produced and stored in channels inside the plant body. stored in channels inside the plant body.

XylemXylem

PhloemPhloem

Vascular Bundles with xylem & phloemVascular Bundles with xylem & phloem

Maize or Corn – vein in cross section

Alfalfa – vein in cross section

Periderm – cork & parenchymaPeriderm – cork & parenchyma

TWIG WITH LENTICELS

Secretory StructuresSecretory Structures nectar (flowers) from nectaries nectar (flowers) from nectaries oils (peanuts, oranges, citrus) from accumulation of oils (peanuts, oranges, citrus) from accumulation of

glands and elaioplasts. glands and elaioplasts. resins (conifers) from resin canals resins (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 to salt glands that shed salt (especial in plants adapted to

environments laden with salt). environments laden with salt).