Abiotic Stess
- Created by: KayshaN
- Created on: 30-10-17 21:37
View mindmap
- Abiotic Stress
- Leaf Loss
- daylight hours and temperature change occurs throughout the year
- A point comes where the glucose needed (respiration) to maintain leaves more than produced by photosyn
- Tree in leaf is more likely to be damaged or blown over
- Lose all leaves and remain dormant until temp increase in spring
- Preventing Freezing
- cytoplasm of cell contain solutes- lower freezing point
- some plants produce sugar, polysaccharides, amino acids, protein- act antifreeze
- Different genes are suppressed and activated in response to low temp.
- Daylight Sensitivity
- Plants sensitive to lack of light
- Lack of light triggers change, this sensitivity is from the pigment- phytochrome
- Abscission
- Lengthening dark periods cause abscission
- fall light levels= fall auxin conc
- leaves respond by producing ethane
- base of leaf is abscission zone, layers sensitive to ethane. Initiates gene switching
- production new enzyme, makes cells weaker called separation layer
- Vascular bundles sealed off and fatty material deposited forming layer prevent pathogen
- cells retain water and swell, leaf separates
- Stomatal Contol
- Heat and water availability, open stomata to cool, close to conserve
- Under control of hormones ABA. Leaf cells release when under stress, bind to receptors on plasma membrane of guard cells
- reduced water potential, guard cells close
- Leaf Loss
Comments
No comments have yet been made