The maximum absorption of UV by DNA is at a wavelength of 254 nm. Maximum mutagenicity also occurs at 254 nm. 

TLS Online TPP Program

#Id: 9848

#Unit 6. System Physiology – Plant

Blue light stimulates the accumulation of anthocyanin (A) and the inhibition of stem elongation by cryptochrome

TLS Online TPP Program

#Id: 9849

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 9850

#Unit 6. System Physiology – Plant

In the light, cry1 is activated directly by blue light and indirectly by blue lightinduced phosphorylation. Activated cry1 forms a complex with COP1 and SPA1 via the C-terminal domain, preventing them from degrading protein targets such as HY5

TLS Online TPP Program

#Id: 9851

#Unit 6. System Physiology – Plant

Both phytochromes and cryptochromes entrain the circadian clock in Arabidopsis.

TLS Online TPP Program

#Id: 9852

#Unit 6. System Physiology – Plant

Blue light depolarizes membrane of hypocotyl cells and inhibits of growth rate.

This membrane depolarization is caused by the activation of anion channels, which facilitates the efflux of anions such as chloride.

TLS Online TPP Program

#Id: 9853

#Unit 6. System Physiology – Plant

an anion channel blocker, NPPB (5-nitro-2-[4-phenylbutylamino]- benzoate), prevents the blue light–dependent membrane depolarization and decreases the inhibitory effect of blue light on hypocotyl elongation.