Topic 6a - Plant structure & nutrient support Flashcards
Non-vascular plants include…
liverworts
mosses
Vascular plants include…
Ferns
gymnosperms & angiosperms (seed plants)
Monocot characterisation…?
flowers in threes leaves - smooth parallel veins stems - scattered vascular bundles roots - fibrous seeds - 1 cotyledon (seed leaf)
Dicot characteristics…?
flowers - 4's or 5's leaves - net-like veins stems - vascular bundles form ring around stem roots - taproot system seeds - 2 cotyledons (seed leaves)
Characteristics of Meristem cells…
undifferentiated
divide mitotically -> meristem cells and/or differentiated cells
Characteristics of differentiated cells…
mature
specialised for specific functions
Apical meristems are located where? Resultant growth termed…?
located at tips of roots & shoots
…termed primary growth -> develops into leaves & buds
Lateral meristems located… Resultant growth termed…?
around perimeter of stems, roots & branches
…termed secondary growth
3 main plant tissue systems?
- dermal (outer)
- ground (mid)
- vascular (inner) typically
A bit more on dermal tissue… (location, function, types)
outermost layer
primarily protective
2 main types - epidermis (young), periderm (older)
A bit about ground tissue…
The “meat” of the plant. (middle)
3 types
What are the 3 types of ground tissue? Function? Eg’s?
parenchyma - photosynthesis, nutrient storage, hormone secretion (eg potato)
collenchyma - mainly support (e.g. celery stalk)
sclerenchyma - mainly support & protection (e.g. pear)
Vascular tissue… function? types?
vessels transporting water & nutrients thru plant
2 types - xylem & phloem
Functions of xylem… types?
transport of water & minerals from roots to shoots via pores
2 types of vessels - tracheids & vessel elements
Function of phloem? types?
transport dissolved nutrients & hormones (in any direction)
2 types - sieve tube elements & companion cells
A bit about stems… functions
support for leaves (major function)
Also transport water, nutrients & photosynthate
Dicot stem - primary growth functions…
support
storage (starch)
photosynthesis
Difference between primary & secondary growth of dicot stems?
primary has: primary phloem & xylem & vascular cambium
secondary has: primary AND secondary phloem & xylem AND DIVIDING vascular cambium
Roots functions?
anchor the plant
uptake & storage of water & minerals
Nutrients in roots taken up by … transport?
active
Define rhizosymbionts…
assist roots in nutrient uptake
2 kinds - mycorrhizae & nitrogen-fixing bacteria
Water enters … via …?
root xylem via osmosis
What is transpiration? What ‘theory’ is involved?
mechanism allowing transport of water many meters to leaves
“cohesion-tension” theory involved
Describe “cohesion-tension” theory. Out loud!
Water enters vascular cylinder of root -> cohesion of water molecules via H-bonds creates water chain -> evaporates thru stomata
What is stomatal control of transpiration? Involves a balance between …?
allowing entry to CO2 & allowing loss of water
Explain water transpiration via stomatal opening (looks like green anus)…
K+ enters guard cells -> water follows -> guard cells lengthen & bend outward -> pore (green anus) opens
What stimulates movement of K+ (re. stomatal opening)?
light (movement inward) low CO2 (inward) absidic acid (outward)
Describe pressure-flow theory…
sugars move to sites of high [ ] (sources) -> sites of low [ ] (sinks) how??
high [ ] of sugar at source draws water in by osmosis -> increase pressure
[ ] of sugar decreased at sinks
thus pressure differential causes net movement from source to sink
