01:119:116 Lecture Notes - Lecture 11: Meristem, Axillary Bud, Auxin
14 Mar 2016
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Document Summary
Plant hormonal control ch 39. 2: introduction, plant hormones, organic compounds- chemical messengers, control specific physiological responses, plant growth regulators, general characteristics. Interact with each other: natural and synthetic, tropisms, directional growth response. Produced by an environmental stimulus: directional. Ex: phototropism- light: 8 major classes of plant hormones table 39. 1. Auxins: first plant hormone that was discovered, charles darwin and son. 1: darwin"s" experiments, phototropism, coleoptile figure 38. 9b. 1st part of grass seedling to emerge from soil. Exposed to light (only from 1 direction) figure 39. 5. Bend toward light: phototropism experiment, auxin, group of natural and artificial hormones. Most common and physiologically important natural auxin. Main site of production is shoot apical meristem. Transport: polar (unidirectional) down shoot- root axis, active- atp. Cell elongation- main functions: stimulate cell elongation in developing shoots, cell wall is elongating, cell wall. Primary wall- cellulose fibers capable of being changed. Secondary wall- save cells: cellulose + lignin. 2: unable to expand, mechanism- acid growth hypothesis.
