Flashcards in 5.4 Plant Responses To Abiotic Stress Deck (28):
Trees loose their leaves in winter due to seasonal changes affecting what?
The amount of photosynthesis possible
Trees loose their leaves at the point when the amount of glucose for respiration in the leaves is greater than what?
The amount of glucose photosynthesis can produce
(Antifreeze) if cells freeze what happens to their membranes?
They are disrupted and they die
(Antifreeze) the cytoplasm of plant cells and vacuoles contain what and what do they do?
Lowering freezing points
(Antifreeze) some plants produce what which act as antifreeze?
Sugars or amino acids
(Antifreeze) these sugars and amino acids prevent the cytoplasm from freezing or protect what?
Cells from damage if they do freeze
(Antifreeze) most plants only produce antifreeze when?
(Antifreeze) different genes are suppressed and activated in response to what?
Temperature and day length preparing plants for frosty conditions
(Stomatal control) plants can respond to stress by doing what to their stomata?
Open them allowing them to evaporate cooling the plant
Closing them to conserve water
(Stomatal control) is controlled by which hormone?
(Stomatal control) roots use ABA to warn of what?
(Stomatal control) 1. There is a decrease in what?
(Stomatal control) 2. The roots produce what?
(Stomatal control) 3. ABA is transported where?
(Stomatal control) 4. ABA binds to what in the leaves?
Receptors on guard cells
(Stomatal control) 5. Binding activates changing in the what of guard cells?
(Stomatal control) 6. Changes in the ionic concentration have what effect?
Reduce water potential and turgid of cells
So guard cells close the stomata
(Abscission) what is abscission triggered by?
The lengthening of the dark period
(Abscission) 1. Levels of what fall?
(Abscission) 2. Concentration of what falls?
(Abscission) 3. Leaves respond by producing what?
(Abscission)4. Ethene initiates gene switching where?
In the abscission zone - 2 layers of cells sensitive to ethene
(Abscission) 4. Causes production of what?
New enzymes digesting and weakening cell walls in the separation layer
(Abscission) 5. What is sealed off?
Vascular bundles a carrying materials into and out of the leaf
(Abscission) 6. Fatty material is deposited where?
Cells on the stem side of the separation layer
(Abscission) 7. The layer forms what?
A protective scar preventing pathogen entry when the leaf falls
(Abscission) 8. Cells in the separation zone retain what?
Water causing them to swell putting more strain in the outer layer