Week 6: Plant Adaptations Flashcards
In seed plants, stem growth initiates at the…
Apical meristem
The apical meristem cells have what 4 qualities?
- Totipotent
- Capable of dividing
- Found near the shoot tips
- Found in axillary buds
Branching in stems occurs at the…
Axillary buds
Tropism is the?
Bending of an organism in response to an external stimulus
What 2 types of tropism affects plants in 2 different ways?
- Plant stems are positively phototropic and negatively gravitropic
- Plants roots are negatively phototropic and positively gravitropic
Where is auxin produced?
In the apical meristem
In plant stems, what is the effect of auxin?
In plant stems, auxin causes cell elongation
In plant roots, what is the effect of auxin?
In plant roots, auxin causes cell shortening
In roots, what senses gravity?
Statoliths - large starch filled organelles
Describe how statolith’s affect directional root growth?
Statolith’s settle at the bottom of cells directing auxin to this lower side of the root causing slowed cell elongation and the root to consequently bend downwards in a positively gravitopic manner
Name the 2 types of vascular tissue found in plants
- Xylem
2. Phloem
What is the function of xylem?
To transport water and nutrients from the roots to the leaves
What is the function of the phloem?
To transport carbohydrates from the leaves to the rest of the plant
Describe basal resistance
Plasma receptors recognise and respond by binding to a molecule produced by a pathogen and producing a defensive response so no infection occurs
Describe specific resistance
Specific resistance relies on specific R proteins that are coded for response to a particular pathogenic AVR protein that can then deactivate the VR gene to there is no virulent response
