1 / 8

The redistribution of auxin during gravitropism in maize roots

The redistribution of auxin during gravitropism in maize roots. Developmental effects of auxin. ¤ Regulate apical dominance ¤ Promote lateral and adventitious root formation – even though auxin inhibit the primary root elongation ¤ Delay the onset of leaf abscission

caleb-bauer
Download Presentation

The redistribution of auxin during gravitropism in maize roots

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. The redistribution of auxin during gravitropism in maize roots

  2. Developmental effects of auxin ¤ Regulate apical dominance ¤ Promote lateral and adventitious root formation – even though auxin inhibit the primary root elongation ¤ Delay the onset of leaf abscission ¤ Regulate the floral bud development ¤ Promote fruit development ¤ Induce vascular differentiation

  3. Developmental effects of auxin ¤ Regulate apical dominance ¤ Promote lateral and adventitious root formation – even though auxin inhibit the primary root elongation ¤ Delay the onset of leaf abscission ¤ Regulate the floral bud development ¤ Promote fruit development ¤ Induce vascular differentiation

  4. Regulate apical dominance– apical bud inhibits the growth lateral buds + IAA inhibits the growth of lateral buds + TIBA (efflux inhibitor) in lanolin placed below the shoot apex  Axillary bud formation Direct-inhibition model  Auxin is synthesized in the shoot apex and is transported basipetally to the axillary buds ( [auxin] gradient)  axillary buds are more sensitive to auxin than other shoot tissues

  5. However ¤ After decapitation 4 h, the level of IAA is 5-fold increase ¤ Applied auxin directly to terminal bud, [auxin]shoot, axillary bud outgrowth ¤ radiolabeled auxin does not enter basipetal the bud ¤ axr1 mutant (unable to respond to auxin), much branching phenotype ¤ Transgenic plant (02): auxin-responsive promoter + luciferase (LUX) gene decapitated  the expression of LUX increase in and around the axillary buds ¤ After decapitation, an increase in cytokinin imported from root via xylem, Add cytokinin in axillary buds  bud growth (but bud growth prior to the increase of cytokinin) ¤ After decapitation, ABA level decrease, in some species. ¤ Carotenoid cleavage product ¤ Grafting studies Root signals interact with auxin in the xylem ongoing research Web Essay 19.4

  6. Auxin induce vascular differentiation– is polar and occurs from leaves to roots Auxin  Cytokinin  Xylem and phloem differentiation: high auxin conc. Only phloem differentiation: low auxin conc.

  7. Auxin promote fruit development produce auxin

  8. The commercial uses of synthetic auxins ¤ prevention of fruit and leaf drop ¤ promotion of flowering ¤ induction of parthenocarpic fruits – seedless fruits ¤ thinning of fruit ¤ rooting of cutting ¤ herbicide for dicot weeds

More Related