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Roots - Coggle Diagram

- - - - grows down trunk until it reaches soil
        
        grows to engulf tree trunk
        
        kills tree by lack of sunlight
  - - - modified roots to feed on the body of other plants
        
        can crack or penetrate to gain entrance
        
        perform little photosynthesis, gain most all nutrients parasitically
  - - - conversion of atmospheric nitrogen to useable compounds
      - symbiotically done by Rhizobium bacteria
        
        infection thread penetrates into inner cortex
        
        root nodule forms, engulfing bacterium
        
        plant exchanges sugars for nitrogen
  - - - 2 types of relationships
        
        ectomycorrhizal relationship
        
        fungi remain on surface
        
        endomycorrhizal association
        
        fungi penetrate into cell
        
        cannot pass endodermis
  - - - causes bulbs to become further buried
      - holds base of shoot at ground level
      - cortex cells change shape
        
        shorten and expand
  - - - root epidermis, several layers of dead cells
        
        waterproof barrier, water cannot leave cell
  - - - grow until they touch ground
        
        begin transporting nutrients up
        
        contract, providing stability to trunk
        
        act like guy wires
      - buttress roots
        
        protect from being blown over by wind
  - - - root only permanent organ
        
        used to produce new shoot in spring
      - perennial plants stay living
        
        root protects energy stores from predation
- - - - cells in middle grow forward
      - cells on sides grow outwards
      - cells detect gravity through grains in cell
        
        cell structure changes when closer to the edge
        
        life of a cell=4-5days
        
        ER shrinks, mucus produced, middle lamella broken down
  - - - does not produce primordia, traces, or axillary buds
    - - act as a reserve of healthy cells
        
        allows root to resume growth after damage
      - cell division does not occur
  - - - no cells mature, but begin to differentiate
        
        protoderm->epidermis
        
        provascular tissue->primary xylem & phloem
        
        closest to meristem
        
        become metaxylem & metaphloem
        
        uniform parenchyma->root cortex
  - - - 1 root hairs grow outward
      - 2 thin cuticle appears
      - 3 zone of elongation morphs into zone of maturation
    - - cylinder that surrounds vascular tissue
        
        minerals blocked from vasculature
        
        walls encrusted with lignin and suberin
      - Casparian strips
        
        bands on walls that control what enters
    - - xylem & phloem mature
        
        both are different than in stems
      - separated from endodermis by Pericycle
  - - - previously thought to be passageway for minerals
      - now known as slowly developing Casparian strips
    - - mature endodermis is entirely waterproof
        
        causes strong pull on water, allows proper gas exchange
      - younger endodermis is not waterproof
- - - - small collection becomes another root apical meristem
- - - - Plant's main carbohydrate storage
        
        carrots, beets, radishes
        
        embryonic root=Radicle
      - often have smaller types coming off
        
        Lateral Roots
        
        can give rise to more lateral roots
        
        results in highly branched system
        
        Branch Roots
    - - results from early dying radicle
        
        lots of similarly sized roots
        
        adventitious roots
        
        arise from stem tissue directly
  - - - protected by root cap
        
        mucigel
        
        complex secretion from root cap
        
        consists of polysaccharides
        
        lubricates passage of root
        
        causes soil to release nutrients
    - - a few mm long
        
        cells undergo division and expansion
        
        behind root apical meristem
    - - trichomes extending from root
        
        form only in stationary areas
        
        behind zone of elongation
        
        greatly increase surface area
        
        important for root function