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Plant responses to the biotic environment

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Plant-animal relationship Herbivores eat plants in many ways graze, browse, sapsuckers, nectar feeders, stem borers, chewers, pollen feeders, fruit eaters, ... – PowerPoint PPT presentation

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Title: Plant responses to the biotic environment


1
Plant responses to the biotic environment
2
  • The resources that are important for plants are
    light, water, minerals, oxygen, carbon dioxide
    and space. Plants also need to defend themselves
    against herbivores.

3
Plant-plant relationships
  • Many plants secrete a poisonous substance into
    the soil to prevent other plants growing near
    them allelopathy.
  • Seed dispersal means spread over a wide area to
    ensure survival.
  • Plants in reduced light grow larger leaves

4
  • Stratification means plants are adapted to
    different light intensities to grow in different
    conditions.
  • Epiphytes are plants that perch on tall trees to
    get light at higher intensities. Lianas are
    plants that climb tall trees for the same reason.
  • Plant parasites true suck the sap and do not
    photosynthesise, hemi-parasites suck the water
    but do own photosynthesis.

5
  • Seaweeds are adapted to different depths green
    at surface, brown mid depth and red deepest.
  • Cluster growing different species grow close
    together to support each other (mainly grasses).
  • Fruit trees rely on others to pollinate (pears,
    feijoas)
  • Clover benefits other plants growing near due to
    the bacteria in their roots.

6
Plant-fungi relationships
  • Mycorrhizal fungi forms mutulistic relationships
    with many plant roots. Very important in pine
    forests in NZ. They help plants absorb water and
    get nutrients in return.
  • A lichen is an obligate mutulistic relationship.
    It is an algae and a fungi that have to live
    together to survive.

7
Plant-animal relationship
  • Herbivores eat plants in many ways graze,
    browse, sapsuckers, nectar feeders, stem borers,
    chewers, pollen feeders, fruit eaters, seed
    eaters, gum eaters.
  • Plant defences against herbivores
  • Thorns modified side branches, spines modified
    leaves and stings which are modified hairs.
  • Divarication plants that branch at wide angles
    with closely interlaced branches.

8
  • Chemicals toxic or just bad tasting, some plants
    produce antibiotics when attacked (caffeine,
    chilli), chemicals produced when chewed (cyanide,
    pyrethins, tannins, nicotine, strychnine etc., or
    smells released to stop animals landing on them
    (onion, garlic etc).
  • Sticky sap or seeds to trap would be eaters
  • Low growing point to recover quickly
  • Enclosing seeds in hard shell or prickles
  • Seed masting
  • Hiding
  • Regeneration
  • Waxy cuticle and epidermis

9
Co-operative relationships between plants
  • The presence of one species of plant growing near
    another may protect it from grazers marigold
    roots secrete a nematode killing chemical that
    helps other plants nearby, willows and alders can
    communicate by airborne chemical cues to develop
    insect resistant chemicals.

10
Co-operative relationships between plant and
animals
  • Pollination
  • Ant guarding
  • Living among thorns
  • Eating succulent fruit
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