1. Kingdom Plantae: Plant Structure
Life Science
Chapter 12

2. Form and Structure
Plants: living organisms which are eukaryotic and multicellular, with organized tissues (especially conducting tissues), plastids (such as green chloroplasts), and cell walls containing cellulose.

3. Form and Structure Morphology – the shape or form of an organism
Anatomy – the bodily structure of an organism; how the cells and tissues are put together
Important because the exterior shape and interior structure of plants often determine where a plant can grow, how it functions, and how it can be used by man.

4. Plant Organs Most plants have four main types of organs: Roots Stems
Leaves
Flowers

5. Plant Organs Determined by their relationships to Nodes:
Node – a region where a leaf is or was attached
Roots DO NOT have nodes
Stems DO have nodes
Leaves DO NOT have nodes but are attached to stems at nodes

6. Roots Two main systems:
Tap root – has one or only a few main roots that are thicker and longer than other roots of the plant
Lateral roots – smaller roots which branch from the main root
Fibrous root – has a cluster of roots that are about equal in size; may branch several times

8. Stems Two main types of stems:
Woody – very hard, firm, and inflexible; capable of supporting a lot of weight; often start as herbaceous but grow into woody stems
Herbaceous – softer and more flexible; contains some supporting cells in the stems but not as many as the woody stem; uses Turgor pressure to stand straight

9. Leaves Three main parts of a leaf: Simple – one leaf
Blade – the flat, green part
Vein – the water- and sugar-conducting tissues
Petiole – the part of the leaf between the node and the blade
Simple – one leaf
Compound – many leaflets

10. Leaves Blade edges: Lobed – several indentations within leaf
Toothed – edge is saw-like or has jags
Smooth – no teeth

11. Veins Three main types of venation:
Parallel – veins run parallel to each other
Palmate – veins meet at a common point at the petiole
Pinnate – one main vein running the length of the leaf with smaller veins extending to the edge

13. Petiole The point of connection between the node and the leaf
The veins the leaf blade converge and follow through the petiole to the stem

14. Leaf Arrangements Three common arrangements:
Alternate – one leaf per node
Opposite – two leaves per node
Whorled – three or more leaves per node
Leaf arrangements help in identifying plants.

16. Plant Anatomy Support: Plant: Cellulose creating stiff cell walls
Turgor Pressure caused by the presence of water in the cells
Plant:
All living plant cells contain plastids, though not necessarily green chloroplasts.
Some green or red (Tomatoes) chloroplasts, some store starch or oil

17. Plant Tissues
Xylem – made of long, hollow cells; carries water from roots through the stem to the leaves
Wood – a collection of layers of xylem that have been formed during several years; tree rings
Phloem – carries sugar solution from the leaves to the growing plants

18. Vascularized bundles – a grouping of xylem and phloem tubules
leaves, young plants, and non-woody plants contain vascularized bundles
Fibers – long, narrow cells (not hollow) that are VERY strong; often found grouped together to form a fiber tissue
Can be used to make rope and cloth

19. Epidermis – thin, flat cells; effective barrier against loss of water; the outermost tissue of leaves, young roots, and young stems;
Secretes a waxy substance that forms the cuticle – protective coating
Bark – layer just outside the xylem; innermost layer of bark makes newest xylem and phloem cells

20. Cork – dead cells with thick cell walls; form a tough, waterproof coating that keeps harmful organisms out and moisture in.
Cork cambium – layer of living cells just inside the dead cell; constantly dividing and producing new cells

21. Major Plant Groups Three main categories: Nonvascular
Seedless Vascular
Seeded Vascular

22. Nonvascular Diffusion is used to transport water and other materials
Fairly short
Live near water and in shady places

23. Bryophytes
Mosses – have structures that resemble leaves and roots but are not true leaves and roots because they do not have vascular tissue
Two parts always present:
Green part – used for sexual reproduction
Rootlike part – anchors plant

24. Seedless Vascular
Plants can grow taller because of the water and material transport system; require water for sexual reproduction
Ferns
“leaves” are called fronds; appear as coils; spores are produced on the underside of the frond
Rhizome – underground stem
Roots – grow from rhizome into
ground

25. Seeded Vascular Reproduce by seeds not spores
Do not rely on water for sexual reproduction therefore can live in wet or dry areas.
Seeds are multicellular; contain a young plant (embryo); abundant energy reserves; barriers for protection
Gymnosperm – “naked seed” - limited barriers
Pine trees – seeds are exposed
Angiosperm – “covered seed” – completely protected seed inside of the fruit