RESUMO
BACKGROUND: Iron (Fe) deficiency chlorosis, a major nutritional problem in plants growing on calcareous soils, is related to the content and reactivity of soil iron oxides and carbonates. The effects of other soil components, however, need elucidation. In this paper we tested the hypothesis that application of high doses of phosphorus (P) to the soil can aggravate Fe chlorosis. RESULTS: Lupin and sorghum were grown on 24 calcareous soils. Leaf chlorophyll concentration (LCC) in lupin decreased with increasing available P/available Fe ratio in the native soil but LCC in sorghum was unaffected by that ratio. Application of P to the soil resulted in significant reduction of LCC and dry weight in lupin. In sorghum, LCC and dry weight were positively affected by P fertilisation for soils poor in available P whereas the opposite effect was generally observed for the P-rich soils. In another experiment where olive plants were pot-grown on two soils during the 20092011 period, P fertilisation affected LCC negatively only in 2009 and 2011 and in the soil that was poorer in iron oxides. CONCLUSION: Application of fertiliser P to Fe chlorosis-inducing soils is likely to aggravate this deficiency. However, this effect depends on the plant and the Fe and P statuses of the soil.
Assuntos
Fosfatos de Cálcio/intoxicação , Fertilizantes/toxicidade , Deficiências de Ferro , Lupinus/efeitos dos fármacos , Doenças das Plantas/induzido quimicamente , Folhas de Planta/efeitos dos fármacos , Solo/química , Fosfatos de Cálcio/metabolismo , Clorofila/análise , Clorofila/biossíntese , Resistência à Doença , Compostos Férricos/análise , Compostos Férricos/antagonistas & inibidores , Compostos Férricos/química , Compostos Férricos/metabolismo , Ferro/análise , Ferro/metabolismo , Lupinus/crescimento & desenvolvimento , Lupinus/metabolismo , Olea/efeitos dos fármacos , Olea/crescimento & desenvolvimento , Olea/metabolismo , Fósforo/análise , Fósforo/metabolismo , Fósforo/toxicidade , Doenças das Plantas/prevenção & controle , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Distribuição Aleatória , Solubilidade , Sorghum/efeitos dos fármacos , Sorghum/crescimento & desenvolvimento , Sorghum/metabolismo , Espanha , Especificidade da EspécieRESUMO
A four-year-old girl presented with accidental ingestion of 200 tablets of Calcarea phosphorica. Although she was asymptomatic, she was found to have marked hypocalcaemia with a prolonged QTc interval on electrocardiogram. She was successfully treated with intravenous calcium, followed by oral maintenance.
Assuntos
Fosfatos de Cálcio/intoxicação , Hipocalcemia/induzido quimicamente , Cálcio/administração & dosagem , Pré-Escolar , Eletrocardiografia , Feminino , Humanos , Hipocalcemia/tratamento farmacológico , Hipocalcemia/fisiopatologia , Síndrome do QT Longo/induzido quimicamente , Síndrome do QT Longo/tratamento farmacológico , Síndrome do QT Longo/fisiopatologia , Resultado do TratamentoRESUMO
High mortality in 1-week-old commercial turkey poults was attributed to the accidental substitution of dicalcium phosphate in the diet for corn. At necropsy of the affected birds, lesions were observed in the upper gastrointestinal tract, suggesting acute ingestion of a caustic substance. Mortality and gross and microscopic lesions were reproduced experimentally in turkey poults fed diets similar to the diet fed in the field case. The cause of these lesions was attributed to increased pH due to the phosphoric acid content of the diet.