UMD BSCI 442 - Photomorphogenesis and Skotomorphogenesis (4 pages)

Previewing page 1 of 4 page document View the full content.
View Full Document

Photomorphogenesis and Skotomorphogenesis



Previewing page 1 of actual document.

View the full content.
View Full Document
View Full Document

Photomorphogenesis and Skotomorphogenesis

24 views

Lecture Notes


Pages:
4
School:
University of Maryland, College Park
Course:
Bsci 442 - Plant Physiology

Unformatted text preview:

Photomorphogenesis OUTLINE Effect of light on Growth and Development Light quality and quantity are the most significant environmental factors affecting plant development Light induces dramatic changes in morphology and biochemical protein composition How does light induce such changes e g increase in rubisco LHC A Simple Model of Signal induced Responses 1 Signal perception by a receptor 2 Signal transduction a Communicate signal to other cell parts b Amplify the signal c Network and cross talk 3 Primary response e g Increase or decrease in gene expression e g Change from inactive protein active protein 4 Cellular and Physiological responses Plants have 3 types of Photoreceptors 1 Phytochrome 660 nm 2 Blue light receptor 400 500 nm 3 UV B Receptors 300 nm Examples of responses mediated by phytochrome light receptor Figure 17 2 Lettuce seed germination LFR Photomorphogenesis and Skotomorphogenesis Figure 17 5 Inhibition of hypocotyl elongation in dark grown lettuce seedlings HIR PhyB UVA Blue What is phytochrome 1st receptor discovered in plants Purified from dark grown seedling Figure 17 6 Purified phytochrome absorbs Red and FR light Photoreversible A protein with a chromophore Pr Absorbs R and FR light FR R Pfr Photostationary state Figure 17 7 Pfr 3 85 Structures of Pr and Pfr 1 Light Quantity and Plant Development Figure 17 4 Light quantity matters VLFR very low fluence 1 100 nmol m2 Induce gene expression LHCB Arabidopsis germination LFR Low fluence 1 1000 umole m2 Promote lettuce seed germination Photoreversible HIR High irradiance 10 000 umole m2 10 mmole m2 Inhibit stem elongation synthesis of anthocyanin not photoreversible not photoreversible Light induces conformational changes in the phytochrome molecule Figure 17 8 Phytochrome Family Figure 17 13 Difference in phytochrome gene family structure Multiple phytochrome encoding genes I Light liable form PHYA Pfr Abundant in dark grown seedling Unstable in light degraded II Light stable form PHYB stable form



View Full Document

Access the best Study Guides, Lecture Notes and Practice Exams

Loading Unlocking...
Login

Join to view Photomorphogenesis and Skotomorphogenesis and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Photomorphogenesis and Skotomorphogenesis and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?