Structure-function photodynamic herbicidal studies of phenanthroline, dipyridyl and pyridine analogs

[摘要] Physical-chemical properties of photodynamic modulators were studied in johnsongrass seedlings and their structure-function relationships were analyzed. The results showed that all three groups of modulators induced DV-MPE formation. DV-Pchlide formation was induced by phenanthroline and dipyridyl analogs and was inhibited by pyridine analogs. The photodynamic damage of seedlings treated with phenanthroline analogs, both in the presence and absence of exogenous ALA, was correlated with positive charge repelling electrostatic volumes around the molecules. The photodynamic damage in seedlings, sprayed with dipyridyl analogs without exogenous ALA, was correlated with electron density over the lowest unoccupied molecular orbital and in seedlings sprayed with modulator + ALA was correlated with negative steric probe volumes of the molecules. In seedlings sprayed with pyridine analogs, both in the presence and absence of exogenous ALA, a correlation was found between photodynamic damage and positive charge repelling electrostatic volumes around the molecules.Incubation of isolated cucumber chloroplasts with different exogenous tetrapyrroles under light showed that DV-Mg-Proto does not trigger chloroplast destruction. DV-Proto affected the PS II antenna Chl pigment-protein complex and had no effect on PS I antenna complex. DV-MPE and MV-Pchlide destroyed the PS I antenna complex completely and disorganized the LHCP complex. DV-Pchlide disorganized the PS I and II antenna complexes.

[关键词] Biology, Plant Physiology