1. Plant Cells, Tissues, and Systems
Sec C3.1
Unit C

2. Objectives
describe the specialized structures and functions of cells in the leaf system
explain the transport system in plants
relate a multi-cellular level of organization with cell, tissue, and system specialization

3. Multicellular vs Unicellular
What are the advantages to having a large structure with lots of cells?
Division of Labour
When a cell is specialized (performs a particular function), it is more effective and efficient.
A single-celled organism must multi-task (do many jobs).

4. Multicellular vs Unicellular
Size
The surface area to volume ratio and related rate of diffusion restricts growth in unicellular organisms.
Efficient transport systems within multicellular organisms allow for growth.

5. Multicellular vs Unicellular
Interdependence of Cells
A single-celled organism is dependent on that one cell.
If a multicellular organism loses a cell, the entire organism will not die. However, a cell not functioning properly (ex. cancerous) can cause problems for the rest of the organism.

6. Plant Structure
Plants are multicellular: made of many parts, each with its own function – organized in increasing complex levels of organization
Tissues= group of cells performing same function together
Organs= tissues contributing to same function
System= group of interconnected organs (two in plants)
Shoot system  everything above ground
Root system  everything below ground and aerial roots

8. What about animals?
What are some examples of tissues, organs and systems in humans?
Ex. Heart/cardiac tissue  heart  circulatory system

9. Do now
Find the definition/function associated with each of the following terms (workbook - chart)
Meristem
Dermal tissue/epidermis
Cuticle
Ground tissue
Vascular tissue
Xylem tissue
Phloem tissue
Sieve tube cells
Companion cells

10. How did you do? Meristem- growth areas
Dermal tissue/epidermis- outer layer of cells; responsible for exchange of matter and gases and protection
Cuticle- waxy substance; resists attack and prevents water loss
Ground tissue- majority of plant; strength and support (stem); food and water storage (roots); site of photosynthesis (leaves)

11. How did you do?
Vascular tissue- transport of materials; xylem and phloem
Xylem- moves water and minerals from roots to leaves; thick, non-living, perforated cells
Phloem- transports sucrose and other sugars from leaves to other parts; made of sieve cells
Sieve tube cells- form continuous ducts; perforated
Companion cells- direct activity of sieve tube cells

12. Plant Growth
Cells divide to grow and repair damage. This cell division is called mitosis.
In plants, increase in size results from the cell division in growth areas called meristems
Rapidly dividing cells - Cell walls thin, nuclei are large, vacuoles, small or absent

13. Meristems
Onion root tip – note different stages of mitosis (cell division)

14. Specialization of Cells
Once cells are no longer in the meristem, they will specialize
Produce products only for their function
The root and shoot systems are made up of 3 types of tissues:
Dermal Tissue (epidermis)
Ground Tissue
Vascular Tissue

15. Types of Tissue Dermal Tissue
Outer layer of cells that covers all herbaceous (non-woody) plants.
Responsible for exchange of matter and gases into and out of the plant.
Also protects the plant from disease. This is done by the cuticle (waxy substance), which resists attacks from micro-organisms and helps reduce water loss.

16. Types of Tissue Ground Tissue
Found underneath epidermis, it makes up majority of plant.
Provides strength and support to the plant (stem).
Involved in food and water storage (roots).
Location of photosynthesis (leaves).

17. Types of Tissue Vascular Tissue
Responsible for transport of material, which occurs in xylem tissue and phloem tissue

18. Vascular Tissue - xylem
Cells in xylem tissue allow transport of water
Die when differentiate leaving empty tubes
Long fibres in celery are vascular tissue (both xylem and phloem)

19. Vascular Tissue - phloem
Phloem Tissue
Formed from long sieve tube cells (no nuclei), which are connected with companion cells (nucleated) that direct activity.
Transports carbohydrates and water from the leaves to other parts of the plant.

20. Leaf Cross section

21. Vascular Tissue

22. Vascular tissue
From: at 4:14

23. Vascular Bundles

24. Sieve tubes

25. More specialization: Roots
Cells in root system will produce tiny hair-like projections called root hairs
Why is this beneficial for the plant?
Increases the surface area for absorption of water

26. Root hairs

27. Root hairs

28. More … Dermal cells in shoot system produce a cuticle
Why is this beneficial?
Prevents water loss

29. And last… Lower epidermis in leaves have guard cells
Form tiny pores called stomata for gas exchange
Only cells with chloroplasts
Why is this important?
Photosynthesis!

30. Leaf Cross section

31. Leaf Cross section
Can you indentify some of the structures?

33. How does water move up the plant?
Gravity should pull water down – how does it move up from the roots to the leaves? How do all these specializations allow for this? Shall be investigating this in this section.
ture=related