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Repair and regeneration

Repair and regeneration. Injury program includes:. Damage control. Abscission. Injury program. Vascular repair. Primordium activation (dormant buds). New organ initiation. Primary signals. O 2 C 2 H 4 MeJ or SA Δ [IAA] Δ [CK] Response to injury is local &/or systemic . PAL. aa.

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Repair and regeneration

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  1. Repair and regeneration Injury program includes: Damage control Abscission Injury program Vascular repair Primordium activation (dormant buds) New organ initiation

  2. Primary signals O2 C2H4 MeJ or SA Δ [IAA] Δ [CK] • Response to injury is local &/or systemic

  3. PAL aa Chalcone synthase Systemic = upregulation of PAL and chalcone synthase Damage control, ‘immune’ response in whole body Phenylalanine Wall crosslinks + + IAA transport Oligos C2H4 MeJ SA + Cinnamic acid - Ferulic acid + Cinnamyl CoA Lignin + + Chalcone Suberin Proteinase inhibitors Chitinase Flavonoids Phytoalexins

  4. Local response might involve vascular repair Cork forms over injury Parenchyma cells de-differentiate  procambium  vascular tissue • Dedifferentiation doesn’t occur until vasculature is broken • IAA and CK activate dedifferentiation

  5. Local response may include organ replacement Dormant primordia released • Leaf • Axillary/lateral buds • Stem primordia • Root Root external view of primordia

  6. Hormones affect apical dominance;injury to SAM or RAM Stem IAA  apical dominance CK made in roots CK  axillary/lateral bud growth What happens if herbivore removes SAM? Root CK  Root Apical dominance What happens if something chomps on root tip? + + IAA - IAA + + + CK + +

  7. Applying what we know Cuttings of stems, tubers, corms • Hybrids • Seedless plants Tissue culture • Orchids; transgenic species; nursery species

  8. Shoot program - + Callus CK IAA - + Root program How do we regenerate organs? Injury causes: Parenchyma cells to dedifferentiate  callus Hormone concentrations to change Relative [IAA] : [CK] important Higher [IAA] promotes root program Higher [CK] promotes stem program

  9. How else do we apply what we know? Injury, moisture and darkness • Layering • Grafting

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