Identification and biological activity of germination-inhibiting long-chain fatty acids in animal-waste composts.
Long-chain fatty acids in germination-inhibiting animal-waste composts were identified by gas chromatography-mass spectrometry as myristic, palmitic, stearic, oleic, linoleic, and linolenic acids. These acids were found at concentrations greater than 0.25 mg (g dry compost)-1. The identified acids, together with lauric acid, and five kinds of short- and medium-chain fatty acid, were tested for their effects on the germination process of sorghum seeds. The authentic long-chain fatty acids, which were dissolved in a 1:9 (v/v) mixture of methanol and distilled water at 40 mg liter-1, significantly reduced the alpha-amylase activity, physiological water uptake, and ATP content of the germinating seeds during the first 24 h of inhibition, as well as the rate of germination of seeds. Among the tested fatty acids, myristic and palmitic acids were the most potent inhibitors of germination. The inhibitory effects of long-chain fatty acids were stronger than those of the phenolic acids. The short- and medium-chain fatty acids did not have any significant germination-inhibitory effects at 40 mg liter-1. The results indicate that the long-chain fatty acids are the dominant inhibitors of germination in animal-waste composts, and that the inhibition of the alpha-amylase activity in germinating sorghum seeds is one aspect of the mode of action of these long-chain fatty acids.
Marambe
B
B
Faculty of Applied Biological Science, Hiroshima University, Japan.
Nagaoka
T
T
Ando
T
T
D000818:Animals; D002417:Cattle; D002645:Chickens; D005230:Fatty Acids, Nonesterified / Q000032:analysis* / Q000494:pharmacology*; D005243:Feces / Q000737:chemistry*; D013058:Mass Spectrometry; D006109:Poaceae / Q000187:drug effects* / Q000502:physiology; D012639:Seeds / Q000187:drug effects* / Q000502:physiology; D013552:Swine
D005230:Fatty Acids, Nonesterified