BI111 Lecture Notes - Lecture 25: Primordium, Xylem, Caffeine
Document Summary
Plant growth and development: to understand diversity of plant structures and life histories, need to understand role that signal response pathways play in their growth and development. Auxins: mainly indoleaceic acid (iaa, synthesized primarily in shoot apical meristem and young stems and leaves, promotes elongaion of cells, governs growth responses to light and gravity. Auxin efects on stems: frequently promotes axial elongaion of stems, maintains apical dominance, inhibits growth of lateral meristems (branching, promote fruit development (cell division), inhibit leaf abscission, delay senescence. Auxin efects on roots: in roots, promote root iniiaion, growth of pre-exising roots, lateral branching of roots, formaion of adveniious roots. Lateral root formaion: root primordia in pericycle form lateral roots. Gibberellins: ga1 is most common, synthesized in shoot and root ips, increases cell division rate, and cell elongaion. Broccoli and b. oleracea: suppression of lower development. Cabbage and b. oleracea: supression of interned length.