Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
32 Cards in this Set
- Front
- Back
|
What are the 5 classical groups of hormones?
|
Auxin, Gibberellins, Cytokinins, Ethylene, Abscisic acid
|
|
|
Which hormone is a gas?
|
Ethylene
|
|
|
Which two hormones are involved in apical dominance?
|
Auxin and Ethylene
|
|
|
Which hormone is involved in abscission (the shedding of leaves)?
|
ehtylene
|
|
|
What hormone do insects produce that stimulates the formation of galls on leaves?
|
Cytokinin
|
|
|
What element is auxin often dependent on as a second messenger?
|
Calcium
|
|
|
Which two hormones can stimulate parthenocarpic fruits?
|
Auxin and gibberellins
|
|
|
Which hormone is involved in "bolting" in cabbage and normal Growth in dwarf plants?
|
Gibberellin
|
|
|
The three steps in Signal Transduction are...
|
...Reception, Transduction, Induction
|
|
|
What part of the plant is Cytokinins most likely produced?
|
The roots
|
|
|
Which hormone is refered to as the plant stress hormone?
|
Abscisic acid
|
|
|
What are the main actions of auxin?
|
Promotes cambial activity and differentiation of cells into vascular tissue.
Promotes adventitious roots on stems. Stimulates fruit production. Inhibits abscission. Enlarges cells in tropic responses |
|
|
What are the main action of Gibberellins?
|
Induces cell division and elongation.
Breaks seed dormancy. Induces juvenile leaves. Involved in the development of parthenocarpic fruits. |
|
|
What are the main actions of the Cytokinins?
|
In the presence of auxin: stimulates cell division and organogenesis.
Expansion of cotyledons. affect organogenesis. formation of galls. |
|
|
What are the main actions of Ethylene?
|
Inhibits cell expansion.
Inhibits flowering. Involved in fruit ripening. Stimulates breakdown of cell walls. Promotes growth of root hairs. Promotes abscission |
|
|
What are the main actions of Abscisic acid?
|
Promotes seed dormancy.
Opening/closing of stomata. Inhibits stimulating effects of other hormones. |
|
|
What is apical dominance?
|
Where the main stem of the plant is dominant over the lateral stems (ie it grows more strongly)
|
|
|
What are tropisms?
|
A growth response toward (positive) or away (negative) from an external stimulus.
|
|
|
The 3 naturally occurring auxins are...
|
Indole 3 acetic acid (IAA)
4chloro IAA Phenylacetic acid |
|
|
Which is the most common auxin and where is it synthesised?
|
IAA in leaf primordia, young leaves, tips of grasses, developing fruits, seeds, flowers and pollen.
|
|
|
Where in the plant does IAA move?
|
Through the parenchyma of the pith, cortex and vascular tissue (always towards the base of the plant)
|
|
|
What does adaptation imply?
|
A genetically determined capability to acclimate to either sun or shade.
|
|
|
What are three features that optimise the light received?
|
Absorbtion, interception and processing
|
|
|
What are some common features of a sun plant? (opposite for a shade plant)
|
Large cells, small chloroplasts.
Few/thin grana stacks. low chloryphyll/rubisco ratio Small/thick leaves High stomatal conductance High photosynthetic capacity Low leaf area ratio high root:shoot ratio vertical leaf orientation high compensation irradiance |
|
|
What does light interception depend on?
|
Orientation, size, angle, surface features of the photosynthetic organ, arrangement of ph/syn tissues within those organs
|
|
|
Where do the largerst leaves occur?
|
In the rain-forest understorey.
|
|
|
What are some features that can increase light reflection on leaves?
|
Hair, wax, salt crystals.
|
|
|
The costs of higher photosynthesis capacity are...
|
Higher respiration rates in leaves
This rate is due to Increased carbohydrate processing in high light. Increased costs of contructing sun leaves. High costs of maintaining sun leaves. |
|
|
What does absorbtion of excess sunlight lead to?
|
Photo inhibition, less photosynthate per unit of light.
|
|
|
What are xanthophylls?
|
Yellow carotenoids that modulate light energy in leaves.
|
|
|
What is D1?
|
A protein that FACILITATES electron transport. Exists in D1 dissipative centres. If these become damaged the photosystem becomes non functional.
|
|
|
What is rubisco?
|
an enzyme involved in the Calvin cycle that catalyzes the first major step of carbon fixation, a process by which the atoms of atmospheric carbon dioxide are made available to organisms in the form of energy-rich molecules such as glucose.
|
