Chapter 23BIO 392
Floweringplants
Cone-bearingplants
Ferns andtheir relatives
Mosses andtheir relatives
Green algaeancestor
Flowers; SeedsEnclosed in Fruit
Seeds
Water-Conducting(Vascular) Tissue
PLANT STRUCTURE
Remember…• Organisms are
made up of:– Organ
Systems– Organs– Tissues– Cells
• Plants are made up of:• Organ Systems• Organs: Roots, Stems, Leaves• Tissues: Dermal, Vascular,
Ground, Meristematic• Cells: epidermal cells,
tracheids, vessel elements, sieve tube elements, companion cells, parenchyma, collenchyma, sclerenchyma,
Concept Map
include
includes includes includes
includes includes
Section 23-1
Plant Tissues
Dermaltissue
Meristematictissue
Vasculartissue
Groundtissue
Epidermalcells Xylem Phloem Parenchyma
cellsCollenchyma
cellsSchlerenchyma
cells
Tracheids Vesselelements
Sieve tubeelements
Companioncells
PLANT TISSUE SYSTEMS (4)A) MERISTEMATIC Source of new growth
for the entire life of the plant• Primary Growth plants grow taller and
deeper– Only in tips of roots & shoots– Apical meristem “the bud”
• Secondary Growth plants grow wider– Lateral Meristem tissue– (Also known as: vascular or cork cambium)
PLANT TISSUES cont.B) DERMAL TISSUE The outer covering of the
plant, “the skin”– May have waxy covering to prevent water loss
C) VASCULAR TISSUE transports fluids & nutrients throughout the plant,
“the bloodstream”– Xylem transports water– Phloem transports food (sugars made)
D) GROUND TISSUE everything else
3 Plant Organs
• Roots• Stems• Leaves
ROOTSFUNCTION
1. Absorbs water & dissolved nutrients from soil2. Anchors plant & prevents erosion
TYPES:1. Taproots long & thick,
2. Fibrous roots thin & branching
ROOTS cont.STRUCTURE (by tissue)
& TRANSPORT
1. Outer epidermal layera. covered by tiny root hairs – more S.A.b. contain active transport proteins in their cell membranes to pump minerals from soil into plant.c. water follows by osmosis
ROOT STRUCTURE cont.2. Large layer of Ground tissue
a. spongy cortexb. endodermis encloses vascular tissue
i. cells are surrounded by Casparian strips- waterproof barriers that force water
to go through cells, not around.
- Keep flow one way (osmosis)3. Central Vascular cylinder
a. water moves into the xylem b. because it cannot go backward, the only place
to go is up the stemi. “Root Pressure”
STEMSFUNCTION
1. Support; hold leaves up in the sunlight2. Transport substances between roots & leaves
TRANSPORT1. Capillary Action
a. water moves by cohesion from roots b. 1 way
2. Nutrients are transported through stema. in phloemb. in 2 directions
LEAVESFUNCTION
1. Site of Photosynthesis
STRUCTURE1. epidermis is covered by cuticle
a. reduce evaporation2. Mesophyll – specialized ground tissue
a. lots of chloroplastsb. where photosynthesis occurs
3. Veins of xylem & phloem branch
LEAVES cont.SPECIAL STRUCTURES
1. Stomata exterior openings on underside of leaf. Site of gas exchange (pores)a. O2 out b. CO2 inc. water vapor out
2. Guard cells surround and control stomata openings
LEAVES cont.TRANSPORT
1. Water escapes through stomataa. process of transpiration (evaporation)b. as water exits, more is drawn up
through stem from roots2. Stomata open and close to prevent excessive water loss.
Shoots and Roots
Stem