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

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Human, animal and plant physiology resources »