The effect of Fe2+, Co2+ and Zn2+ cations on the development of the photodynamic effect induced by endogenous porphyrins in green plants

It was shown that Fe2+, Co2+ and Zn2+ cations decreased the levels of proto porphyrin IX (PP) and Mg protoporphyrin IX(monomethyl ester) (MP(E)) accumu lated in intact green leaves of Artemisia vulgaris in the presence of 5-ami nolevulinic acid (ALA) and 2,2'-dipyridyl (DP) in darkness. The extent of p hotodamage op the plant under subsequent illumination correlated with the r esidual content of PP and MP(E). The efficiency of cation action depended o n the duration of the dark period after ALA and DP treatment, on the time o f cation treatment and chemical nature of used cations. Treatment of the pl ant with Fe2+ resulted in a maximum effect which could be compared with the influence of CO2+, Zn2+ cations had the weakest effect.