选取岩溶地区花溪河流域典型农业区为研究对象,运用δ^15N-NO3^-,δ^18O-NO3^-和δ^18O-H2O同位素示踪技术和水化学分析方法,阐明了研究区地表水和地下水中硝酸盐的分布特征,并揭示其来源和形成过程,基于R语言下运行的贝叶斯模型(stable...选取岩溶地区花溪河流域典型农业区为研究对象,运用δ^15N-NO3^-,δ^18O-NO3^-和δ^18O-H2O同位素示踪技术和水化学分析方法,阐明了研究区地表水和地下水中硝酸盐的分布特征,并揭示其来源和形成过程,基于R语言下运行的贝叶斯模型(stable isotope analysis in R),对研究区水体中各种硝酸盐来源的贡献比例进行了定量识别.结果显示:受碳酸岩盐风化的控制,流域内地表水和地下水的水化学类型以HCO3-Ca型为主,硝酸盐在研究区水体中的空间分布特征受土地利用类型影响明显;在研究区水体硝酸盐形成过程中,硝化作用起主导作用,水体中的硝酸盐来源主要有化肥、降雨中的氨盐、土壤有机氮、粪便和污水,与地表水相比,地下水中硝酸盐受粪便和污水的影响较大;基于SIAR源解析模型分析,大气沉降、化肥、土壤有机氮和粪便污水对研究区地表水硝酸盐的贡献比例分别为3.97%、26.87%、36.80%和32.37%,对地下水硝酸盐的贡献比例分别为2.83%、13.96%、21.03%和62.18%.展开更多
The volatiles produced by Paenibacillus polymyxa strain BMP-11 which was isolated from the rhizosphere soil of cucumber in a greenhouse were analyzed by SPME-GC-MS.Based on the preliminary test,three kinds of purchase...The volatiles produced by Paenibacillus polymyxa strain BMP-11 which was isolated from the rhizosphere soil of cucumber in a greenhouse were analyzed by SPME-GC-MS.Based on the preliminary test,three kinds of purchased commercial products 1-octen-3-ol,benzothiazole and citronellol were chosen to give further assessment of their bioactivity.Antifungal bioassays in sealed dishes revealed that those three compounds strongly inhibited the mycelia growth of the eight pathogens at a low treatment dosage and induced the mycelial morphological abnormalities.During the experiment,we even found that citronellol completely prevented the pigment production of the tested fungus,Fusarium oxysporum,however,1-octen-3-ol and benzothiazole had slight effect.The germination was inhibited to different degrees when spores of Botrytis cinerea exposed to these compounds for 24 h in water agar plate.Furthermore,fumigation results showed that 1-octen-3-ol and benzothiazole had strong toxicity against Tribolium castaneum,LC50 was 16.76 and 3.50 mg L-1,respectively.The fumigation activity was also found similar to the positive control,1,3-dichloropropene （LC50 =10.13 mg L-1）.Results of herbicidal assays showed that tested compounds had inhibitory effects on the seed germination and seedling growth of Amaranthus retroflexus,Echinochloa crusgalli and Chenopodium album.Findings of the present study suggested that the antifungal,insecticidal and herbicidal properties of the components were contained in volatiles.These agents or even their derivatives may have a potential to be used as fungicide,insecticide as well as herbicide.展开更多
文摘选取岩溶地区花溪河流域典型农业区为研究对象,运用δ^15N-NO3^-,δ^18O-NO3^-和δ^18O-H2O同位素示踪技术和水化学分析方法,阐明了研究区地表水和地下水中硝酸盐的分布特征,并揭示其来源和形成过程,基于R语言下运行的贝叶斯模型(stable isotope analysis in R),对研究区水体中各种硝酸盐来源的贡献比例进行了定量识别.结果显示:受碳酸岩盐风化的控制,流域内地表水和地下水的水化学类型以HCO3-Ca型为主,硝酸盐在研究区水体中的空间分布特征受土地利用类型影响明显;在研究区水体硝酸盐形成过程中,硝化作用起主导作用,水体中的硝酸盐来源主要有化肥、降雨中的氨盐、土壤有机氮、粪便和污水,与地表水相比,地下水中硝酸盐受粪便和污水的影响较大;基于SIAR源解析模型分析,大气沉降、化肥、土壤有机氮和粪便污水对研究区地表水硝酸盐的贡献比例分别为3.97%、26.87%、36.80%和32.37%,对地下水硝酸盐的贡献比例分别为2.83%、13.96%、21.03%和62.18%.
基金funded by the Special Fund for Agro-Scientific Research in the Public Internet of China(200903033)
文摘The volatiles produced by Paenibacillus polymyxa strain BMP-11 which was isolated from the rhizosphere soil of cucumber in a greenhouse were analyzed by SPME-GC-MS.Based on the preliminary test,three kinds of purchased commercial products 1-octen-3-ol,benzothiazole and citronellol were chosen to give further assessment of their bioactivity.Antifungal bioassays in sealed dishes revealed that those three compounds strongly inhibited the mycelia growth of the eight pathogens at a low treatment dosage and induced the mycelial morphological abnormalities.During the experiment,we even found that citronellol completely prevented the pigment production of the tested fungus,Fusarium oxysporum,however,1-octen-3-ol and benzothiazole had slight effect.The germination was inhibited to different degrees when spores of Botrytis cinerea exposed to these compounds for 24 h in water agar plate.Furthermore,fumigation results showed that 1-octen-3-ol and benzothiazole had strong toxicity against Tribolium castaneum,LC50 was 16.76 and 3.50 mg L-1,respectively.The fumigation activity was also found similar to the positive control,1,3-dichloropropene （LC50 =10.13 mg L-1）.Results of herbicidal assays showed that tested compounds had inhibitory effects on the seed germination and seedling growth of Amaranthus retroflexus,Echinochloa crusgalli and Chenopodium album.Findings of the present study suggested that the antifungal,insecticidal and herbicidal properties of the components were contained in volatiles.These agents or even their derivatives may have a potential to be used as fungicide,insecticide as well as herbicide.
