BI111 Lecture Notes - Lecture 28: Brassica Oleracea, Auxin, Cytokinin
Document Summary
Plant growth and development: understand signal resp pathways and how they are involved in growth and dev. Plant hormones: 7 major classes: auxins, gibberellins, cytokinins, ethylene, brassinosteroids, abscisic acide, jasmontes. Of cells: synthesized in: apical meristem of shoot and young stems and leaves, indoleacetic acid iaa, growth resp and orientation to light and gravity. Phototropism in seedlings: sun on one side of shoot tip auxin diffuses down from shoot tip to cells on shaded side auxin stim"d cells elongate faster bending. Cell expansion: acid growth hypoth: increasing turgor cell expansion, auxin triggers pumping of h+ into ell wall expansion breaks cross bridges bt cellulose microfibrils cellulose microfibrils loosen. Auxin effect on stems: freq promo of axial elongation of stem, maintains apical dominance, inhibits growth of lateral meristems branching, promo fruit dev, inhib leaf abscission, delay senescence. Abscission zone: base of leaf where it joins stem, form because decrease in auxin, artificial light interferes with lifespan.
