1. Plant Tissues And Cell Types

2. What is a tissue exactly?
A tissue is a group of cells that are structurally and/or functionally distinct, and that perform a common function.
Tissues composed of just one kind of cell are called simple tissues
While those composed of more than one cell type are called complex tissues.

3. Simple
Complex
Parenchyma is an example of a simple tissue (composed only of parenchyma cells)
xylem is an example of a complex tissue (composed of tracheids, vessel members, parenchyma cells, and sometimes fibers)

4. Tissues are Organized into 3 Systems
Vascular- like the plants blood stream where the transport of water and nutrients occu
Ground – everything between Dermal and Vascular tissues
Dermal- like the skin of the plant

5. All of these tissues were once
Meristematic
This is plant tissue where all of the growth through cell division happens.
If mitosis (cell division) is happening then its meristematic tissue.
Apical meristem is at the tips of shoots and roots
Lateral meristematic tissue is where thickening growth takes place
·vascular cambium
·cork cambium

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

8. Parenchyma

9. Collenchyma

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

11. Epidermis – stoma, trichomes, & root hairs

12. Complex Tissue Vascular Tissues
Xylem – water conducting tissue; parenchyma, fibers, vessels and/or tracheids, and ray cells.
Phloem - food conducting tissue; sieve-tube members (no nucleus at maturity, cytoplasm present), companion cells, fibers, parenchyma, and ray cells. 

13. Xylem

14. Phloem

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

16. Examine a cross section of a Helianthus (sunflower) stem.
Identify the vascular
bundles, xylem, phloem, cortex, pith, and epidermis.
To what tissue system (i.e.,vascular, dermal, and ground tissues) does each of these tissues belong?
Find examples of collenchyma, parenchyma, and sclerenchyma cells.

17. Dicot Stem Epidermis Cortex (Collenchyma) Fiber Cap (Schlerenchyma)
Phloem
Xylem
Pith (Parenchyma)