Amphibians are considered as reliable indicators of environmental quality. In Europe, a general decline of amphibians population parallels a worldwide decline, and some of the factors which are thought to be responsib...Amphibians are considered as reliable indicators of environmental quality. In Europe, a general decline of amphibians population parallels a worldwide decline, and some of the factors which are thought to be responsible to this decline are habitat loss, introduction of exotic species, disease and decreasing water quality. Recent investigations suggest that these eutrophic conditions may be associated with frog reproduction problems. Water quality criteria settled for the different species of amphibians do not currently exist, but in the present paper, the authors report their observation about water phosphate concentrations in association with hipofertility in African clawed frogs （Xenopus laevis）. The study considered two different groups of African clawed frog showing hypofertility （22 patients） hosted in captivity. The animals were visited, and the filtration systems functionality and the water quality were checked, i.e., temperature, pH, ammonia, nitrite, nitrate, phosphates, hardness and alkalinity. In the first group, it was decided to perform ultrasound scans, parasitological tests on fecal samples, and microscopical/macroscopical examination, as well as microbiological analysis on collected oocytes. In the second group, only fecal samples were collected in order to perform parasitologiacal exams. No pathological findings were showed by veterinary tests. Water changes were carried out in both facilities and after two months, the fertility in African clawed frogs improved, evidencing the involvement of phosphates values in the onset of the problem and even more in its resolution. More studies are needed to further define this correlation.展开更多
We aimed to investigate the effects of phosphate treatment on growth dynamics of wheat in wheat/corn intercropping system in southwest hil y area. [Method] Five phosphate fertilization levels were designed for wheat a...We aimed to investigate the effects of phosphate treatment on growth dynamics of wheat in wheat/corn intercropping system in southwest hil y area. [Method] Five phosphate fertilization levels were designed for wheat and corn respectively to investigate the effects of phosphate fertilization level on wheat/corn intercropping system by field block experiment. [Result] The number of til ers, plant height and yield component of wheat trended to increase with the increase of phos-phate fertilization amount and al reached the peak for phosphate fertilization amount of 135 kg/hm2. However, the number of til ers, plant height and yield component of wheat al decreased significantly with the further increase of phosphate fertilization amount. [Conclusion] Phosphate fertilization contributed to the wheat growth in a certain degree. However, excessive phosphate fertilization would affect final yield.展开更多
文摘Amphibians are considered as reliable indicators of environmental quality. In Europe, a general decline of amphibians population parallels a worldwide decline, and some of the factors which are thought to be responsible to this decline are habitat loss, introduction of exotic species, disease and decreasing water quality. Recent investigations suggest that these eutrophic conditions may be associated with frog reproduction problems. Water quality criteria settled for the different species of amphibians do not currently exist, but in the present paper, the authors report their observation about water phosphate concentrations in association with hipofertility in African clawed frogs （Xenopus laevis）. The study considered two different groups of African clawed frog showing hypofertility （22 patients） hosted in captivity. The animals were visited, and the filtration systems functionality and the water quality were checked, i.e., temperature, pH, ammonia, nitrite, nitrate, phosphates, hardness and alkalinity. In the first group, it was decided to perform ultrasound scans, parasitological tests on fecal samples, and microscopical/macroscopical examination, as well as microbiological analysis on collected oocytes. In the second group, only fecal samples were collected in order to perform parasitologiacal exams. No pathological findings were showed by veterinary tests. Water changes were carried out in both facilities and after two months, the fertility in African clawed frogs improved, evidencing the involvement of phosphates values in the onset of the problem and even more in its resolution. More studies are needed to further define this correlation.
文摘We aimed to investigate the effects of phosphate treatment on growth dynamics of wheat in wheat/corn intercropping system in southwest hil y area. [Method] Five phosphate fertilization levels were designed for wheat and corn respectively to investigate the effects of phosphate fertilization level on wheat/corn intercropping system by field block experiment. [Result] The number of til ers, plant height and yield component of wheat trended to increase with the increase of phos-phate fertilization amount and al reached the peak for phosphate fertilization amount of 135 kg/hm2. However, the number of til ers, plant height and yield component of wheat al decreased significantly with the further increase of phosphate fertilization amount. [Conclusion] Phosphate fertilization contributed to the wheat growth in a certain degree. However, excessive phosphate fertilization would affect final yield.
