Photoregulation of the Endogenous cGMP Content in Oat Seedlings

The concentration of cGMP in the tissues of oat (Avena sativaL.) seedlings was shown to depend on seedling age and the light regime of their growth. The level of cGMP in the etiolated seedlings was lower than in the green ones and declined with seedling age. Red and blue light recognized by phytochrome and cryptochrome, respectively, affected the cGMP content. The effectors of cGMP metabolism, guanylin, protoporphyrin IX, and zaprinast, elevated the cGMP content in tissue extracts from oat seedlings.