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红壤的磷肥有效性差异及其土壤化学特点的初步研究 总被引:10,自引:2,他引:10
用发育于玄武岩和花岗岩的红壤及其水稻土作水稻盆栽试验研究红壤的磷肥有效性差异及其土壤化学特点,试验表明,花岗岩发育的红壤及其水田的磷肥有效性与Fe,Al有关,而玄武岩发育者,不仅占Fe,Al,而且还与Mn有密切关系,对土壤-植物系统中磷肥有效性与Fe,Mn元素相互作用及其机理进行了讨论。 相似文献
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荒漠藻类广泛分布于干旱区环境,盐胁迫是影响荒漠藻类生存的重要环境因子,稀土农用及其引起的生态环境问题亦受到广泛关注,为此以一种从荒漠结皮中分离的典型蓝藻——爪哇伪枝藻为材料,在实验室条件下研究盐胁迫和外源稀土元素铈对伪枝藻生理生化特性和细胞结构的影响。试验处理时,先进行铈效应浓度的筛选,然后设置NaCl浓度分别为0(对照)、0.05、0.3 mol.L^-1进行盐胁迫和Ce、Ce+0.05 mol.L^-1 NaCl、Ce+0.3 mol.L^-1 NaCl处理,分别测定各种处理下的藻生物量(以叶绿素a表示)、光合活性(Fv/Fm)、藻蓝蛋白含量、胞外多糖含量、膜脂过氧化产物丙二醛含量和伪枝藻素含量以及超微结构的变化。研究结果表明,与对照处理相比,盐胁迫导致伪枝藻生物量和光合活性的显著降低,胞外多糖出现大量积累,藻蓝蛋白和伪枝藻素含量呈现明显下降,同时导致伪枝藻膜脂丙二醛含量的大量增加和藻细胞超微结构的破坏。添加外源铈的盐胁迫处理发现,铈能够促进伪枝藻细胞的生长活性,并对藻细胞的内部结构具有一定的保护作用,而对藻细胞的藻蓝蛋白、伪枝藻素和胞外多糖的影响并不明显。这表明稀土元素铈对于伪枝藻的生长可能具有一定的调节作用,但对于提高伪枝藻的盐胁迫耐受性作用并不显著。研究结果为更好地理解稀土元素对荒漠藻类的生物学效应提供了有意义的参考,可为稀土在荒漠结皮培植中的应用提供指导。 相似文献
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菠菜是我国蔬菜出口的重要品种之一,其毒死蜱残留量直接关系到我国农产品的出口和消费者的安全.采用气相色谱法(GC-NPD)测定毒死蜱残留量,研究了硝酸稀土对菠菜中毒死蜱残留动态的影响.结果表明,不论是喷施农药之前2 d还是喷施农药之后2d喷施硝酸稀土,不同的硝酸稀土对菠菜中的毒死蜱残留都有不同程度的降解作用,且随着喷药后时间的延长,毒死蜱在菠菜中的残留量逐渐减少.不同时间喷施硝酸稀土,对菠菜中毒死蜱残留降解的效果存在差异,药后喷施的效果优于药前喷施.在硝酸稀土种类的选择上,首先选择对毒死蜱降解效果好的硝酸铈和硝酸钕,其次选择常乐益植素和硝酸镧.根据稀土农用的安全性分析,参考植物性食品中稀土最大残留限量标准,选择硝酸稀土作为农药残留降解制剂用于蔬菜安全生产,在技术上是可行的,人类食用是安全的. 相似文献
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The aim of the present study was to investigate the microbial activity along forest brown soil profiles sequence developed on different lithological substrates (carbonate or non-carbonated cement in sandstone formations) at different altitudes. The main question posed was: does carbonate affect the biochemical activity of brown soil profiles at different altitudes? For the purpose of this study, four soil profiles with different amounts and compositions of SOM developed on different lithological substrates were selected: two with carbonate (MB and MZ) and the other two with non-carbonated cement in the sandstone formations (MF1 and MF2). Chemical and biochemical properties of soil were analysed along soil profiles in order to assess the SOM quantity and quality, namely total organic C (Corg), water extractable organic C (WEOC) and humification indices (HI, DH, HR). Microbial biomass (Cmic and Nmic) content, as well as the specific activities of acid phosphatase, β-glucosidase and chitinase enzymes were chosen as indicators of biochemical activity. The soil biochemical properties provided evidence of better conditions for microorganisms in MB than in MF1, MF2 and MZ soil profiles, since patterns of microbial biomass content and activity might be expected in response to the amount and quality of organic substances. The different lithological substrates did not show any clear effect on soil microbial biomass content, since similar values were obtained in MF1, MF2 (with non-carbonated cement) and MZ (with carbonate). However, the specific activities of acid phosphatase (per unit of Corg and per unit of Cmic) were higher in soils with no carbonate (MF1 and MF2) than in soils with carbonate (MB and MZ). In conclusion, the biochemical activity along brown soil profiles was mainly regulated by different soil organic matter content and quality, while the two different lithological substrates (with carbonate or non-carbonated cement in the sandstone formations) did not show any direct effect on microbial biomass and its activity. However, the activity of acid phosphatase per unit of C was particularly enhanced in soil with non-carbonate cement in the sandstone formations. 相似文献
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水溶液及红壤提取液中镧的生物毒性研究 总被引:2,自引:0,他引:2
利用发光细菌法研究了水溶液及红壤提取液中镧的生物毒性。水溶液中镧有较高的生物毒性并随浓度的升高而增强 ,EC50 值为21.1mg·L-1。土壤提取液中的镧有一定的生物毒性 ,并随镧浓度的升高不断增强。随着培养时间的延长 ,土壤提取液中镧的生物毒性逐渐减小。镧在土壤中的生物毒性是直接的 相似文献
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稀土农用给中国农业带来丰厚回报,但稀土的环境安全问题也引起了中外科学家的关注。本文结合国内外最新研究成果,从稀土细胞毒理学角度概述了稀土在细胞内定位,稀土对细胞膜、细胞器、细胞遗传物质及细胞信使物质的毒理效应,并对稀土细胞毒理学的研究进行了展望。 相似文献
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1992—1993年在由花岗片麻岩发育的黄棕壤上,分别采用饱和D-最优设计与裂区试验设计两种方法作田间试验,研究了不同量的钙硼组合与花生产量的关系及对生长发育的影响,并运用数理分析方法,获得了亩施石灰110-120公斤,硼砂0.7公斤钙硼组合的适宜量. 相似文献