Transcript No Slide Title

Plant Anatomy
Plant Cells
Each plant cell has a central vacuole which
makes the cell much bigger than it would
otherwise be. The plant cell is enclosed by a
cell wall. The tendency of the plant cell to take
in water (by osmosis) is counteracted by the
cell wall which restricts this expansion. This
mutual antagonism makes each cell a turgid
little box. It is this simple construction
principle that allows herbaceous plants with
little or no strengthening material to rise
several feet into the air! (relying on this system
of one turgid box on top of the next!)
Because they cannot move, plants
must be extremely responsive to
environmental cues and have their life
cycle in perfect synchrony with the
seasons. Plants must tide over
inhospitable dry seasons or winters as
seeds, bulbs etc. or in the case of
some trees in a "bare-bones" leafless
state. A plant cannot simply pick itself
up, like an animal, and get out of the
rain!
AND, because they cannot move and
because it is their lot in the web of life to be
eaten by animals, plants have a unique mode
of development. This involves plants
growing by meristems at their tips. Plants
also have remarkable powers of
regeneration. Any single plant cell can
regenerate an entire plant with all its cell
types - a feat no animal can match. A limb
lopped off an animal is certain disaster.
For a plant it just regenerates the
missing portion!
Growth (page 602)
Meristems - cells that divide continually
Kinds of Meristems:
Apical - tips of stems and roots (length)
Lateral - sides of stems and roots
(diameter)
- gymnosperms and dicots
2 Kinds of Lateral:
1. Vascular cambium makes more vascular
tissue
2. Cork cambium makes cork
Specialized Plant Cells
(pgs. 599-600)
Sclerenchyma:
•ridged cell wall
•strengthens areas of NO growth
ex. Gritty texture of pears
Parenchyma:
•loosely packed
•thin, flexible walls
•metabolic functions
(photosynthesis, healing and storage)
ex. Fleshy apple parts
Collenchyma:
•thick cell wall
•Grouped in strands
•Provide support and strength
Ex. Celery stalks
Tissue Systems
Dermal
•Outside covering of plants
•Made up of parenchyma cells = epidermis
•Often covered by a cuticle, a waxy layer,
which prevents water loss
Ground
•Consists of all 3 types of cells
•storage tissue
•metabolism
•support
Vascular:
Made up of xylem and phloem
•sclerenchyma and parenchyma cells
•transports and supports
Xylem
and
Phloem
(in an angiosperm)
Tracheids
vessels
Sieve tube
Companion cells
Plant parts
Kinds:
1. Tap
ex. Carrot
Roots
2. Fibrous
ex. Grass
3. Adventitous prop root
ex. Corn stalk
Function:
Anchors plant
Absorbs nutrients and water
Stores glucose as starch
Stems
Kinds:
Herbacious - soft
Function:
Support
Transport
storage
Woody - hard
Leaves
Kinds:
1. Simple - 1 blade
per petiole (maple)
2. Compound more than 1 blade
(clover)
Function:
Makes glucose
Makes oxygen