title: Photoinductive efficiency of soil extracted humic and fulvic acids.
abstract: Humic and fulvic acids extracted from soils of different genesis were investigated for their ability to photoinduce the transformation of fenuron (2 x 10(-4) mol(-1)) at 365 nm. The ratio of the initial rate of fenuron consumption over the rate of light absorption by humic substances was found to be higher for fulvic acids (range 2.0 x 10(-3) to 9.0 x 10(-5)) than for humic acids (range 1.7 x 10(-4) to - 3.6 x 10(-5)). Within the FAs population, this ratio decreased as the specific absorption coefficient at 365 nm increased. It seems therefore that most of 365-nm absorbing components have no photoinductive activity and even reduce that of photoinductive chromophores.
mesh_terms: D001578:Benzopyrans / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002623:Chemistry Techniques, Analytical / Q000379:methods; D006812:Humic Substances / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008027:Light; D010671:Phenylurea Compounds / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects; D010777:Photochemistry / Q000379:methods*; D011827:Radiation; D012987:Soil
chemical_list: D001578:Benzopyrans; D006812:Humic Substances; D010671:Phenylurea Compounds; D012987:Soil; C010727:fenuron; C005023:fulvic acid