Plant Tissues and Organs
Fig. 38.6
Modular construction of a shoot
Basic Plant Morphology
• TISSUES- a group of cells functioning together in some
specialized activity
• MERISTEMS- a mass of self-perpetuating cells, which
are not yet committed to developing into a specialized cell
type
– Terminal meristems- ends of stems, branches
and roots
– Axillary meristems- base of leaves, branches
– Lateral meristems are parallel to sides of plant
parts and increase girth.
Meristem types
• Primary
– Apical Meristems
• Secondary
– Vascular cambium
– Cork Cambium
Flowering plants have 3 basic tissue
types
• Dermal
– Cover surface of plant
– Protection
• Ground
• Vascular
– Conducting tissue
Dermal
• Epidermis
– epidermal cells
• Periderm
– cork cells
Fig. 38.12a
Fig. 38.12b
Fig. 38.12c
Vascular Tissue
• Xylem
– Mostly to conduct water and nutrients
– E.g., roots to shoots
• Phloem
– Mostly to conduct sugars, amino acids, etc.
– E.g., leaves to roots or flowers
Fig. 38.13a
Fig. 4.6
Fig. 4.9
Fig. 38.13b
Fig. 38.14a
Fig. 38.14b
Vegetative Organs
• Roots
• Stems
• Leaves
Function of roots
• Anchor the plant
• Absorb water and minerals from soil
• Storage
Longitudinal section of roots
• Root cap
• Zone of cell division
• Zone of cell
elongation
• Zone of maturation
Cross section of root
•
•
•
•
Vascular bundle (Stele) = contains xylem and phloem
Cortex
Epidermis
Root hairs
– Absorb water and minerals
Fig. 38.15
Fig. 38.21
Function of Stems
• support leaves to maximize light absorption
• part of conduit for transport of water,
minerals, and organic solutes
• storage
Fig. 38.25a
Fig. 38.25b
Woody dicots
• Discrete vascular bundles replaced by
continuous rings of xylem
• Each ring is xylem produced during one
growing season
• Vascular cambium
Fig. 38.7a
Fig. 38.7b
Stems: Secondary growth
•Vascular tissue, (xylem) makes up the bulk of the stem
•Form tree rings
Fig. 38.23
Fig. 38.28a
Fig. 38.28b
Fig. 38.28c
Function of leaves
• Main photosynthetic structure
Leaf parts
• Blade
• Petiole
• Pair of stipules
Fig. 38.34
Fig. 38.8
Fig. 38.33
Fig. 38.30