1. Plants
Tissues part 2
Stem
Leaf

2. Plant TISSUES Dermal Ground Vascular Epidermis (“skin” of plant)
single layer of tightly packed cells that covers & protects plant
Ground
bulk of plant tissue
Photosynthetic
Storage
Vascular
transport system in shoots & roots
xylem & phloem

3. Dermal tissue Epidermis
In stems and leaves has cuticle, a waxy layer that prevents water loss.
Some have trichomes (hairs)
Root epidermis has root hairs

4. Vascular tissue
Transports water and organic materials (sugars) Xylem – transports water and
dissolved ions from the root
to the stem and leaves.
Phloem – carries dissolved sugars
from leaves to rest of the plant

5. Xylem cells Xylem cells are dead!
They are hollow cells and consist only of cell wall

6. Phloem Living cells at functional maturity Cells
Companion cells
Living cells at functional maturity
Transport sugars
cell membrane, cytoplasm
control of diffusion
lose their nucleus, ribosomes & vacuole
more room for specialized transport of liquid food (sucrose)
Cells
sieve tubes
sieve plates — end walls — have pores to facilitate flow of fluid between cells
companion cells
nucleated cells connected to the sieve-tube
help sieve tubes loading material
Sieve plates

7. Ground tissue Makes up the bulk of plant organs.
Functions: Metabolism, storage and support.
Root Stem Leaf

8. Plant Organs Roots Stems Leaves Dermal Vascular Ground Dermal Vascular

9. Root Ground tissue
In roots, ground tissue (a.k.a. cortex) provides support, and
often stores sugars and starch
(for example: yams, sweet potato, etc.)
cortex

10. Root cortex: Casparian strip
The Casparian strip is a water-impermeable strip of waxy material found in the endodermis (innermost layer of the cortex).
Helps to control the uptake of minerals into the xylem

11. Tissues of the Leaf (Epidermis)
Cuticle
Waxy substance that covers the leaves & stems
Waterproof layer that keeps water in plants

12. Tissues of the Leaf (Epidermis)
Stomata
Openings in the epidermis mainly located on the underside of leaves
Exchange of gases

13. Tissues of the Leaf (Epidermis)
Guard Cells
Two cells located on each side of stomata
Open and closes stomata

14. Tissues of the Leaf (Mesophyll Layer)
Palisade mesophyll
Primary site of photosynthesis
Spongy mesophyll
Contains air & chloroplasts
Site of photosynthesis and gas exchange

16. Stems Functions Movement of materials
Water & minerals from roots to leaves
Manufactured food from leaves to roots
Support leaves & reproductive structures
Food storage

17. Internal Stem Structure
Xylem
The tissue that transports water & nutrients up from roots to stems & leaves.
Phloem
Tissue that transports food down from leaves to roots.
Cambium
Thin, green, actively growing tissue located between bark & wood and produces all new stems cells.