Lecture 24 - Plant Growth & Development (part 1) Flashcards
What are plants composed of?
cells, tissues & organs
What is a shoot system?
above ground organs of the plant
What are stems composed of (within the shoot system)?
- Nodes
- Internodes
- Shoot apical meristem (SAM)/Apical buds terminal bud)
- Axillary buds
What are leaves composed of (within the shoot system)?
- Blades
- Petioles
- Veins
What is a root system?
below ground organs of the plant
What are root systems composed of?
- Taproots (eudicots)
- Lateral roots
- Root hairs
- Root apical meristem (RAM)
What is the dermal tissue system?
protective tissue layer
What is the dermal tissue system comprised of?
- epidermis
- cuticle
- periderm
- guard cells
- trichomes
Epidermis
outermost cell layer
- within the dermal tissue system
Cuticle
waxy, protective layer on stems and leaves
- within the dermal tissue system
Periderm
layer in woody plants that REPLACES the epidermis during secondary growth
- within the dermal tissue system
Guard cells
gas exchange
- within the dermal tissue system
Trichomes
hairlike cells that reduce water loss, reflect excess light, defense
- within the dermal tissue system
What is the vascular tissue system?
transport tissue layer
What is the vascular tissue system comprised of?
- Xylem
- Phloem
- Stele
Xylem
water conducting tissue
- within the vascular tissue system
Phloem
transports photosynthates
- within the vascular tissue system
Stele
xylem + phloem
- within the vascular tissue system
What is the function of the ground tissue?
storage, support, & photosynthetic tissue layer
What is the ground tissue system comprised of?
- Pith
* Cortex
Pith
internal to vascular tissue
- within the ground tissue system
Cortex
external to vascular tissue
- within the ground tissue system
Describe Parenchyma cells
- THIN and FLEXIBLE primary cell walls
- LACK secondary cell walls
- Large central VACUOLE
- Perform most of the METABOLIC functions of the plant
- LIVING cells
Chlorenchyma
photosynthetic parenchyma
• Some contain amyloplasts, which STORE STARCH
• Can divide and differentiate to REPAIR TISSUES
- within parenchyma cells
Describe Collenchyma cells
- GROUPED in strands, usually BENEATH the EPIDERMIS
- SUPPORTIVE function, flexible but NOT restrictive
- ELONGATED CELLS with UNevenly thickened primary cell walls
- LIVING cells
Describe Sclerenchyma cells
- Contain secondary cell walls composed of lignin
- Functionally dead at maturity
- Very rigid, structural support
- Sclerids
- Fibres
Sclerids
irregular shaped (gritty texture in pears) - within schlerenchyma cells
Fibres
Long, slender strands, tapered (hemp fibres)
- within schlerenchyma cells
What is apart of Xylem Tissue?
- Tracheids
* Vessel Elements
What is Tracheids (within Xylem Tissue)?
- Tubular, elongated cells with tapered ends
- IN the XYLEM of all vascular plants
- DEAD at maturity, thickened secondary CELL WALLS of LIGNIN
- Water moves BETWEEN cells VIA PITS
What is Vessel Elements (within Xylem Tissue)?
- Wider, shorter elongated cells with less tapering
- ALIGNED end-to-end with PERFORATION PLATES
- IN THE XYLEM of angiosperms, a few gymnosperms, and a few seedless vascular plants
- DEAD at maturity, thickened secondary CELL WALLS OF LIGNIN
What is apart of Phloem Tissue?
- Sieve-tube elements
* Companion cells
What is Sieve-tube elements (within Phloem Tissue)?
- ALIVE, but LACK a nucleus, ribosomes, cytoskeleton, vacuole
- Long, narrow cells CONNECTED by SIEVE PLATES
What is Companion cells (within Phloem Tissue)?
- CONNECTED TO the sieve-tube element
- NON-conducting
- Contains a NUCLEUS & ALL organelles
- Metabolic products are transferred from here TO the sieve-tube elements