BI111 Lecture Notes - Lecture 8: Pollen Tube, Voer, Xylem
Document Summary
Auxins: mainly indoleacetic acid (iaa, synthesized primarily in shoot apial meristem and young stems and leaves, promotes elongation of cells, governs growth responses to light and gravity. Auxin effects on stems: frequently promotes axial elongation of stems, maintains apical dominance, inhibits growth of lateral meristems (branching, promote fruit development (cell division), inhibit leaf abscission, delay senescence. Auxin effects on roots: in roots, promote root initiation, growth of pre-existing roots, lateral branching of roots, formation of adventitious roots, auxinic herbicides selectively kill dicots and spare monocots. Lateral root formation: root primordia in pericycle form lateral roots. Synthesized in plant parts, e. g. roots, flowers, leaves, stems. In response to environmental stress, such as heat stress, water stress, salt stress, soil compaction. Synthesized in green fruits at beginning of winter period. Synthesized in maturing seeds, establishing bud dormancy. Mobile within leaf and can rapidly translocate from the roots to the leaves by the transpiration stream in the xylem.
