BIOL 1120 Lecture Notes - Lecture 20: Senescence, Spinach, Cella
Document Summary
Hormones biochemicals produced in one part of a plant that have their effect on another part of the same plant (2 categories) (table 40. 1: 814-815), growth promoting hormones, auxin (fig. Promotes cell longation a: responsible for various tropisms by promoting differential cell elongation, gravitropism growth in response to gravity (figs. Auxin, together with a growth-inhibiting hormone, may play a role in promoting, or inhibiting, growth in strategic regions. Staliths, which are unbound starch grains in the plastids, respond to gravity and may trigger the redistribution of auxin: phototrophism growth in response to light (figs. Bending toward the light is caused by elongation of cells (auxin stimulation) on the side of the plant not exposed to light. Phototropin 1, a pigment molecule, probably plays a role because of its capacity to absorb blue wavelengths of light: thigotropism growth in response to touch (fig. This response is prevalent in climbing vines and in the tendrils that support some plants.
