Basic plant anatomy 1
* root
* root tip
* root hairs
Plant Body Hierarchy
* Tissue
* Cells with a common function
* Organ
* 3 basic organs
* Roots
* Stems
* Leaves
Roots
* Roots anchor plant in soil, absorb
minerals & water, & store food
* fibrous roots (1)
* mat of thin roots that spread out
* monocots
* tap roots (2)
* 1 large vertical root
* also produces many small lateral,
or branch roots
* dicots
* root hairs (3)
* increase absorptive
surface area
Basic plant anatomy 2
* root
* root tip
* root hairs
* shoot (stem)
* nodes
* internodes
* buds
* terminal or apical buds
* axillary buds
* flower buds & flowers
Modified shoots
Basic plant anatomy 3
* root
* root tip
* root hairs
* shoot (stem)
* nodes
* internodes
* buds
* terminal or apical buds
* axillary buds
* flower buds & flowers
* leaves
* mesophyll tissue
* veins (vascular bundles)
Leaves
* Function of leaves
* photosynthesis
* energy production
* CHO production
* gas exchange
* transpiration
Modified leaves
Interdependent systems
* Both systems depend on the other
* roots depend on sugars produced by photosynthetic leaves
* shoots depend on water & minerals absorbed from the soil by roots
Plant TISSUES
* Dermal
* epidermis (“skin” of plant)
* single layer of tightly packed cells that covers
& protects plant
* Ground
* bulk of plant tissue
* photosynthetic mesophyll, storage
* Vascular
* transport system in
shoots & roots
* xylem & phloem
Plant CELL types in plant tissues
* Parenchyma
* “typical” plant cells = least specialized
* photosynthetic cells, storage cells
* tissue of leaves, stem, fruit, storage roots
* Collenchyma
* unevenly thickened primary walls
* support
* Sclerenchyma
* very thick, “woody” secondary walls
* support
* rigid cells that can’t elongate
* dead at functional maturity
Parenchyma
Collenchyma
Sclerenchyma
* Thick, rigid cell wall
* lignin (wood)
* cannot elongate
* mostly dead at maturity
* Cells for support
* xylem vessels
* xylem tracheids
* fibers
* rope fibers
* sclereids
* nutshells
* seed coats
* grittiness in pears
Phloem: food-conducting cells
Phloem: food-conducting cells
Phloem
* Living cells at functional maturity
* 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
Vascular tissue in stems
Vascular tissue in roots: dicot
Vascular tissue in roots: monocot
Putting it all together
* Obtaining raw materials
* sunlight
* leaves = solar collectors
* CO2
* stomates = gas exchange
* H2O
* uptake from roots
* nutrients
* uptake from roots
Plant Growth
* Apical meristem
* Growth in length
* Primary
* Lateral meristem
* Growth in diameter
* Secondary
Growth in woody plants
* Woody plants grow in height from tip
* primary growth
* apical meristem
* Woody plants grow in diameter from sides
* secondary growth
* lateral meristems
* vascular cambium
* makes 2° phloem & 2° xylem
* cork cambium
* makes bark
Primary growth of roots
* Root cap
* Protects root as it grows
* Cell division (mitosis)
* Cells small
* Cell elongation
* Cell differentiation
* Cells mature into
final cell types
Primary growth of stems
* Shoot apical meristem
* Dividing cells at shoot tip
* Develop from axillary bud on stem’s surface
Secondary plant growth: vascular cambium
* Adds secondary xylem & phloem
* Thickens roots & stems
* Heartwood
* Close to center
* Does not transport water
* Sapwood
* Transport xylem sap
* Outer layers
Secondary plant growth: cork cambium
* Periderm
* Cork cambium & tissues
* Produces thick covering
* Protects from water loss
* Phelloderm
* Thin layer of parenchyma
* Secondary tissue
* Exterior of cork cambium
* Suberin - waxy
