RESUMO
The noxious weed Nassella neesiana is established on a wide range of productive land throughout southeastern Australia. N. neesiana seeds, when mature, are sharp, causing injury to livestock, thus posing a problem in fodder bales. To reduce infestations of agricultural weeds in situ, production of silage from weed-infested pastures is practised as part of integrated weed management (IWM). However, there is little data to demonstrate whether this process is useful to reduce infestations or the harmful properties of N. neesiana. Therefore, the minimum duration of ensilage required to reduce the viability of N. neesiana seeds was investigated, both with and without addition of ensilage inoculants in this process. Also, the decreasing propensity of the seeds to injure livestock, after various times and conditions of ensilage, was assessed. Ensilage inoculant reduced seed germination probability to zero after 35 days. When no inoculant was added, zero viability was achieved after 42 days. A qualitative assessment of the hardness of ensilaged seeds found seed husks were softer (and therefore safer) after 42 days, whether inoculant was used or not. Therefore, we suggest that both the viability of N. neesiana seeds and hardness of seed casings are significantly reduced after 42 days, thereby reducing the risks of seed dispersal and injury to livestock.
Assuntos
Plantas Daninhas/efeitos adversos , Poaceae/efeitos adversos , Sementes/efeitos adversos , Silagem/efeitos adversos , Controle de Plantas Daninhas/métodos , Animais , Austrália , Germinação , GadoAssuntos
Antibacterianos/farmacologia , Enterobacteriaceae/isolamento & purificação , Répteis/microbiologia , Animais , Cloranfenicol/farmacologia , Resistência Microbiana a Medicamentos , Enterobacteriaceae/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Fezes/microbiologia , Geografia , Indonésia , Klebsiella/efeitos dos fármacos , Klebsiella/isolamento & purificação , Mamíferos/microbiologia , Testes de Sensibilidade Microbiana , Especificidade da EspécieRESUMO
Water-lead levels were measured in the homes occupied during the first year of life by 77 mentally retarded children aged two to six years and 77 non-retarded matched controls, and in the homes occupied by their mothers during pregnancy. The water-lead content was significantly higher in the retarded group, and the probability of mental retardation was significantly increased when water lead exceeded 800 mug. per litre. Blood-lead levels were also significantly higher in the retarded group. It is concluded that lead contamination of water may be one factor in the multifactorial aetiology of mental retardation and that every effort should be made to reduce the lead content of drinking-water.
