The effect of natural and artificial seed ageing has been compared in terms of physiological and biochemical responses of several maize genotypes. The physiological parameters were: viability, germinability, emergence in sand and dry matter accumulation. The biochemical parameters were: DNA synthesis and DNA polymerase activity. A close and direct relationship was found between seed deterioration and DNA metabolism in all maize materials which responded to ageing according to their genetic constitution; i.e., vigorous genotypes suffered less severe damage or recovery was faster than in the low-vigour genotypes. Coordination of events at appropriate times would seem a critical factor for proper seed germination.
Leachate from a composting plant was characterized and applied as a biofertilizer in lettuce crops. Characteristics of untreated (UE) and anaerobically treated (TE) leachate samples were compared. The pH of TE (8.2) increased in relation to the UE (5.2) due to an increase in ammonia nitrogen in TE (1197 mg L-1) compared to UE (859 mg L-1). Anaerobic treatment was efficient in the removal of organic matter from the leachate, evaluated by the decrease of dissolved organic carbon, biochemical oxygen demand, total organic carbon and total solids. K presented the highest concentration (1743 mg L-1) in TE, followed by Mg (135 mg L-1). Cd, Pb and Cr were present at low concentrations in the samples, 0.047, 0.206 and 0.081 mg L-1, respectively. Salmonella, thermotolerant coliforms and viable helminth eggs were not present in TE, which was applied as a biofertilizer in a lettuce crop and compared to mineral fertilization based on fresh matter and dry matter production. Lettuce production using TE was statistically equivalent to mineral fertilization. Toxic metals were not detected in the lettuce shoots. It was concluded that the anaerobically treated leachate from the composting company has the potential to be used as a biofertilizer.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.