Plants in Space

• Ecological Niche is the way an organism is adapted to response to the habitat in which it lives
• Niche is the combination of where an organism lives, How it lives (Its role)

  Adaptation may Include

  Structural

  Behavioural

  Psychological
• Fundamental niche is all environmental conditions were met

  Limits set by tolerance to Abiotic (Non-living) Factors
• Realised Niche is the Actual Niche - Liimits include Biotic - Intraspecific
• For Realised Niche

  The greater the overlap , the greater the Intraspecific Competition

  If nicher are too similar , one specie may eliminate / Outcompete the other
• Gause's principle - one specie may eliminate- outcompete the other - more likely occur if the niche of two species are too similar
• Orientation responses includes Innate which are genetically determined behaviour
• Orientation Responses also allow organisms to avoide unfavourable conditions / Find favourable environmental conditions
• Tropisms - Associated with Auxins - Growth movement +ve (towards) ot -ve away to an external stimulus

  Direction of Stimulus Determines Growth Direction
• Types of Tropism

  Phototropism - Light (+ve) - Associated to Auxin

  Geo / Gravitropism - Gravity (+ve) - Associatied to Auxin

  Chemo - Chemical - Toxins / Acid (-ve)

  Thigmo - Touch (+ve)

  Hydro - Water (+ve)
• Auxins are mainly associated to

  Phototropism

  Gravotropism
• Auxins produce on tips of Stem and roots

  Diffusion down the tip PROMOTE elongations cells - Stems (Root Growth)

  High Auxin Conc. means Higher Cell Elongation in Stems

  A) Stem - Region of Elongation

  
• If Auxin Conc. is unequal in eigther side of the stem ,

  Cells will elongate more on one side = Stem Bending
• Stem will ben towards the light source +ve phototropism

  In roots, High Auxin. Conc. Inhibit Cell Elong - Auxin Concentrate on Lower side of Roots

  This will then result in Cell to Bend Downwards (-ve) Gravitropism
• Nastic Movement are rapidly reversible movements - response to changes in Intensity of Stimulus NOT DIRECTIONAL
• Nastic Movements includes

  Thigmonasty - e.g Carnivorous Fly Traps

  Photonasty - Opening of Flowers at dusk

  Thermonasty - II II
• Rapid Movement of Plant leaves = Usually result to change in Turgor Pressure at the base of the stem of the leaf