01:119:116 Lecture Notes - Lecture 10: Usain Bolt, Cytokinin, Auxin
19 Jul 2018
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In plants = growth regulators, have multiple effects. Tropisms - directional growth, +/-; growing towards or away from stimulus (usually light) Signal must be coming from tip to control phototropism. Note, they will ask about the conditions on the exam. Darwin s experiments - phototropism in plants, shielded or removed coleoptile tip. Some signal is transmitted downward from tip to elongating region of coleoptile. Polar and active; promotes growth towards food or light sources, controls apical dominance. Fruit development (seeds produce auxins -> fruit development (greenhouse tomatoes)) Introduction to plant hormones: auxin, cytokinins, abscisic acid (aba) Modifies apical dominance, concentration in the roots/low parts of stems, Cytokinesis promotes lateral elongation, stimulates cell division and pant elongation. Experiment-undifferentiated plant cells tissue culture: auxin & no cytokinin -> grow large, but do not divide, with cytokinins only -> no effect (b/c need both, with cytokinins and auxin -> grow and divide.
