BIOL 1106 Lecture Notes - Lecture 5: Cryptochrome, Cell Division, Ethylene

• School: Virginia Tech
• Department: Biological Sciences
• Course: BIOL 1106
• Professor: Jack Evans

Document Summary

Pigments allow plants to test the quality of air and the surrounding environmental conditions: photomorphogenesis- refers to non-directional light triggered development, phytochrome- pigment containing protein involved in photomorphogenesis, uses light for information, exists in two different forms- Pr- stands for phytochrome red, absorbs close light, biologically inactive. Pfr- stands for phytochrome far red, absorbs far red light at 730 nm, biologically active form. Seed germination- inhibited by far red light and stimulated by red light (shade= far red light, sun= red light) Etiolation- shoot elongation response that begin growth in the dark, are frail and tiny. Stems are usually phototropic to light with blue wavelength and roots to light without blue wavelength. Phototropins 1 and 2- auxin is involved: circadian clocks- leaf movements in plants occur in a 24-hour cycle (leaves lower and night and raise during the day) Gravitropism- make the roots go down: roots are positively gravitropic and shoots are negatively gravitropic.