plant form chapter 36. plant classes seed producing plants: –gymnosperms –angiosperms...

Plant Form

Chapter 36

Plant Classes

• Seed producing plants:– Gymnosperms– Angiosperms

• Dicotyledons (dicots)

• Monocotyledons (monocots)

2

Plant Classes

3

Plant Body Organization

All vascular plants consist of:

• Root system

• Shoot system

4

• 3 basic tissue types

5

DermalGround

Vascular

Plant Growth

6

• Adult cell growth is limited.• Growth and development of adult plants is dependent on specialized cells called meristems.

Apical Meristem• Located at tips

of stems and roots.

7

8

Lateral Meristem

• Produce wood and bark in trees and bushes – called secondary growth.

Vascular Tissue - Xylem

• Main water-transportation tissue

• Also transports dissolved minerals, NO3

and PO4.

• Provides stem support.

9

• Principal food-conducting tissue in vascular plants

• Carries glucose and starch created during photosynthesis

10

Vascular Tissue - Phloem

Roots

• Four regions are commonly recognized:

– Root cap

– Zone of cell division

– Zone of elongation

– Zone of maturation

11

12

Stages in the differentiation of plant tissues

Modified Roots

• Most plants produce either/or:– Taproot system – single large root with small

branch roots– Fibrous root system – many small roots of

similar diameter– Some plants, however, produce modified

roots with specific functions– Adventitious roots arise from any place other

than the plant’s root

13

14

Prop roots Aerial roots

Pneumatophores Water storage roots

Buttress roots

Stems

• Undergo growth from cell division in apical and lateral stems

• Shoot apical meristem cells create stem tissue as well as leaves, other shoots, and flowers.

15

16

Parts of the Stem

17

Monocot stemEudicot (Dicot) stem

Leaves

• Principal site of photosynthesis

• Expand by cell division and cell enlargement

• Growth stops at maturity

18

19

Leaf Structure

•Cuticle•Epidermis•Palisade mesophyll•Spongy mesophyll•Vascular bundles•Guard cells•Stoma

Modified Leaves

20

Bracts

Spines

Insectivorous

Reproductive