FORMATION OF MONOVINYL AND DIVINYL DERIVATIVES OF MAGMESIUM-PROTOPORPHYRIN-IX MONOMETHYL ESTER AND PROTOCHLOROPHYLLIDE IN MONOCOTS

We studied the chemical heterogeneity of Mg-protoporphyrin IX monometh yl ester and protochlorophyllide (PC) in etiolated, greening, and gree n plants under normal conditions and after their treatment with 5-amin olevulinic acid (ALA) or ALA in combination with the chelator of metal s 2,2'- dipyridyl. In contrast to dicots, the studied monocots (cereal s in particular) show only monovinyl (MV) PC under conditions of etiol ation or during shading of greening and green plants. Under conditions of shading, divinyl (DV) PC appears only in plants supplied with exog enous ALA, in the presence of which an increase occurs in the number o f functioning chlorophyll biosynthesis centers (CBC) transforming ALA into PC. The behavior of DV-PC corresponds to that of an intermediate, namely the natural precursor of MV-PC in biosynthesis. Activating the link of exogenous ALA synthesis, light actuates all CBC, and formatio n of DV-PC begins to be clearly registered also.