Ch 35 Plant Structure and Development Flashcards
What percentage of plants are angiosperms?
90%
Two main groups of angiosperms
1) Monocots
2) Dicots
Monocots
Palms, grasses, orchids, lilies
Eudictos
Most everything except water lilies and magnolias
Monocot embryo
One cotyledon
Eudicot embryo
Two cotyledons
Monocot leaf venation
Veins usually parallel
Eudicot leaf venation
Veins usually netlike
Monocot stems
Vascular tissue scattered
Eudicot stems
Vascular tissue usually arranged in ring
Shoot system
Responsible for light and CO2 acquisition and photosynthesis
Root system
Responsible for water and mineral acquisition
Functions of the root
1) Anchoring the plant
2) Absorbing minerals and water
3) Storing carbohydrates
Most eudicots and gymnosperms have what kind of root system?
A taproot system
A taproot system consists of:
1) Taproot
2) Lateral roots
Taproot
Main vertical root
Lateral roots
Arise from the taproot or adventitious root
Most monocots have what kind of root system?
A fibrous root system
A fibrous root system consists of:
1) Adventitious roots
2) Lateral roots
Adventitious roots
Arise from stems or leaves
Where does absorption occur in roots?
At roots hairs
Root hairs
Thin, tubular extension of root cells
A stem consists of:
1) Alternating system of nodes
2) Internodes
Nodes
The points at which leaves are attached
Internodes
The stem segments between nodes
Axillary bud
A structure that has the potential to form a lateral shoot
Lateral shoot
A branch
Apical bud
Causes elongation of a young shoot
An apical bud is located where?
Near the shoot tip
Apical dominance
Helps to maintain dormancy in most axillary buds
The major axes of stem growth are in line with what?
The apical buds
Leaf
Main photosynthetic organ of most vascular plants
Leaf parts
1) Flattened blade
2) Petiole
Petiole
A stalk that joins the leaf to a node of the stem
What do axillary buds indicate?
Where a single leaf begins
Each plant organ has what three things?
Dermal, vascular, and ground tissues
Dermal
Outer protective covering
In nonwoody plants, what form does the dermal layer take?
It is present as a single layer of epidermal cells
Vascular
Transports materials between plant organs, namely the roots and shoots
Ground
Involved in support, storage, and metabolism
In nonwoody plants the dermal tissue system consists of:
1) Epidermis
2) Cuticle
Periderm
Replaces the epidermis in older regions of stems and roots in woody plants
Trichomes
Outgrowths of the shoot epidermis
What can trichomes help with?
Infect defense
Two vascular tissues:
1) Xylem
2) Phloem
Xylem
Conveys water and dissolved minerals upward from roots into the shoots
Phloem
Transports organic nutrients from where they are made to where they are needed
Tissues that are neither dermal nor vascular are what?
Ground tissue
Ground tissues include what?
Cells specialized for strorage, photosynthesis, and support
What kind of cells are usually the primary site of photosynthesis?
Ground tissue cells of the leaves (mesophyll)
Plant growth occurs indeterminately at ___
Meristems
Meristems
Regions of embryonic growth
Primary growth
Lengthening of stems
Where does primary growth occur?
At apical meristems
Root cap
Protects the apical meristems at the end of a root
How is a root cap pushed through the soil?
By cell division, elongation, and differentiation
Where does secondary growth occur?
Lateral meristems
Secondary growth
Increasing thickness/width of woody plants
Two lateral meristems
1) Vascular cambium
2) Cork cambium
Vascular cambium
Adds layers secondary xylem and secondary phloem
Cork cambium
Replaces the epidermis with periderm
Periderm
Thicker and tougher than the epidermis
In cross section, what does the vascular cambium appear as?
A ring of stem cells
Stem cells in plants increase what?
The vascular cambium’s circumference
Stem cells in plants add what?
Secondary xylem to the inside and secondary phloem to the outside
