Protoheme formation in barley in response to light, dark and delta‐amino levulinic acid

abstract

The influence of Delta‐amino levulinic acid (ALA), synthesized in etiolated barley leaves on the formation of the porphyrins protoheme and protochlorophyll, was examined. A significant amount of protoheme was found under light‐flash conditions which produced high concentrations of ALA but kept low the production of chlorophyllide. Increases In protoheme were also observed after 24 hours of continuous light. It was considered significant that protoheme did not increase in dark‐held controls in which trace amounts of ALA were detected. The content of protoheme seemed to be a reflection of ALA availability. The chlorophyll content after 24 hours of continuous Illumination was about 100 times greater than that of photoconvertable protochlorophyl11de accumulated in etiolated leaves. Results suggest that light‐induced ALA in etiolated barley was utilized for the production of protoheme and chlorophyll.

Key words:

• Chlorophyllide
• Delta‐Amino levulinic acid
• Protoheme
• Protochlorophyll