BIOLOGY 2D03 Lecture Notes - Lecture 6: Pfr, Usage-Based Insurance, Phytochrome
28 Oct 2016
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Document Summary
Perception of light by photoreceptors: plants perceive quantity, quality (wavelength), and direction of light, use photoreceptors to detect wavelengths, different wavelengths = different environments (shaded, time of day, directionality) Seedling development: dark (skotomorphogenesis, adapative light-seeking response in which seedlings respond by becoming etiolated to grow towards light. How do plants sense the light and initiate the proper response: experiment: find genes controlling these developmental pathways using mutant screens, look for mutant plants with. Dark-grown phenotype when grown in light (impairment in sensing or responding to light) Light-grown seedlings when grown in dark (impairment in sensing or responding to darkness: identified hy mutants (hy = hypocotyl, hy1, hy2, hy3 genes encode enzymes involved in synthesis of phytochrome receptors. Phytochrome receptors allow plants to perceive light and initiate photo/skotomorphogensis. Phytochrome receptors: apoprotein & prosthetic group (chromopore, 2 forms of phytochromes. Pr and pfr form interconvert in presence of red/far-red light.
