Molybdenum and Copper Uptake by Forage Grasses and Legumes Grown on a Metal‐Contaminated Sludge Site

Abstract

Wastes applied to agricultural land can contain significant concentrations of bioavailable molybdenum (Mo). Because Mo uptake by forage crops could lead to hypocuprosis in ruminants, more knowledge is needed about which crops are most efficient in accumulating Mo. At an old sewage sludge‐amended site, the concentrations of Mo, copper (Cu), and several other trace metals were measured in various grass species. Generally, the grasses grown on the sludge site contained higher Mo concentrations than the same species grown on a nearby control site. However, because Cu concentrations were also higher in the sludge‐grown grasses, Cu:Mo ratios in the grasses were frequently higher on the sludge site. In contrast, all legumes tested (alfalfa, birdsfoot trefoil, red clover, pea), as well as canola and beets, had lower Cu:Mo ratios when grown on the sludge site. Sulfur concentrations in the two crops analyzed for this element (canola and pea) were higher on the sludge site than the control. It is concluded that Mo, Cu, and sulfur (S) bioavailability remains elevated in the soil several decades after sewage sludge application.     

高钼低铜对小鼠睾丸组织脂质过氧化作用的影响

为研究高钼、低铜及两因素协同作用对小鼠睾丸组织脂质过氧化作用的影响,将80只健康雄性昆明系小鼠随机分为4组,分别为对照组(Cu 3 mg/L,Mo 0 mg/L)、高钼组(Cu 3 mg/L,Mo600 mg/L)、低铜组(Cu 0 mg/L,Mo 0 mg/L)、低钼高铜组(Cu 0 mg/L,M0 600 mg/L...     

盐碱地中溶磷真菌的筛选及培养条件优化

为缓解板结土壤中由于不溶性磷酸盐的积累过多对土壤造成的板结问题,从东北长期板结土壤中筛选出多株具有溶磷能力的溶磷真菌。通过解磷圈测量及钼蓝比色法对分别以磷酸钙、磷酸铝及磷酸铁为主的培养物中可溶性磷含量进行测定,获得了1株溶磷能力较大的菌株P10,其对磷酸钙、磷酸铝及磷酸铁的分解能力分别为250,13,31μg/m L,经分子生物学鉴定,该菌株为具疣蓝状菌(Vorte plave gljivice)。该菌的最佳碳源、氮源、p H及底物磷酸钙用量分别为蔗糖、大豆粉、p H 6.0及10 g/kg,优化后,可溶性磷含量达378μg/m L。     

大豆连作微量元素营养研究Ⅱ.连作对钼营养的影响

本文通过田间与盆栽对比试验及室内分析相结合的方法,研究了大豆连作胁迫下钼营养的变化特征。结果表明：不同连作年限播前土壤有效钼的含量低于正茬。不同生育期各连作年限土壤有效钼的变化趋势和植株钼的积累特征与正茬相似,但含量低于正茬,且在盛花期土壤有效钼降到钼营养临界值（０．１ｍｇ／ｋｇ）附近,结荚期低于临界值。结荚期连作大豆土壤和植株钼营养与根瘤固氮、植株氮营养及产量间相关显著或极显著。上述结果说明,连作胁迫导致的钼营养亏缺可能是连作大豆产量降低的一个重要原因。此外,本文还探讨了连作大豆土壤有效钼降低的原因。     

重金属钼离子单抗的制备及其免疫学特性研究

为了检测水质、土壤、食品中的重金属钼离子的残留,故制备用于钼离子检测用的单克隆抗体。采用已合成的钼离子人工抗原Mo6+-ITCBE-BSA免疫Balb/C小鼠,用间接ELISA和间接竞争ELISA法筛选出备用小鼠,用细胞融合技术筛选制作单克隆抗体。结果表明:筛选出4株特异性强、敏感度高的杂交瘤细胞,其中4B3杂交瘤细胞株间接ELISA检测培养上清抗体效价为1∶(3.6×102);体内诱生法制备腹水效价为1∶(5.12×105);杂交瘤核型鉴定结果显示4B3杂交瘤细胞株染色体数目平均为99.4。4B3杂交瘤细胞株用间接竞争ELISA结果显示,IC50值为23.4μg/L,与Cr3+-EDTA的交叉反应率为81.8%,与其他金属螯合物无交叉反应。说明Mo6+-EDTA-mAb可用于Mo6+污染检测的免疫学试验。     

低温胁迫下钼对冬小麦抗氧化酶活性的影响

【目的】揭示钼提高冬小麦抗寒力的生理机制。【方法】采用盆栽试验的方法，以冬小麦钼高效品种97003和钼低效品种97014为材料，研究了在低温胁迫下施钼对冬小麦叶片抗氧化酶活性影响。【结果】低温处理2、4和6 d时施钼均显著提高了超氧化物歧化酶（SOD）、过氧化氢酶（CAT ）、过氧化物酶（POD）和抗坏血酸过氧化物酶（APX）活性，显著降低了2个冬小麦品种叶片中超氧阴离子产生速率；施钼后，随着低温胁迫时间的延长，2个冬小麦品种叶片中4种抗氧化酶活性均先升高而后呈下降或突降趋势，说明施钼能使冬小麦通过正常的低温锻炼过程，有利于植株在经受更长时间低温胁迫时维持较高的抗寒力；钼对冬小麦钼高、低效品种叶片中抗氧化酶活性的影响存在基因型差异，与钼高效品种相比，钼低效品种缺钼处理叶片SOD、CAT、POD和APX等抗氧化酶活性下降幅度更大，活性氧自由基积累速率更大，这可能是钼低效品种在缺钼条件下更易受到低温伤害的原因之一。【结论】钼通过调控活性氧代谢过程来影响冬小麦的抗寒力。     

The influence of variations in soil copper on the yield and nutrition of spinach grown in microplots on two organic soils

Abstract

Spinach (Spinacia oleracea L. cv. Symphony) was grown in spring 1982 in field microplots of an organic soil (site I a mucky peat) containing 81 to 1063 μg Cu.g^‐1 soil, and cv. America of the same crop taken in summer 1982 on a peaty organic soil (site II) varying in Cu content from 13 to 1659 μg.g^‐1. The variations in soil Cu were mainly due to three rates of Cu applications in 1978 at site II and in 1979 at site I. At site I, the diversity in soil‐Cu had no effect on yield or foliar‐Cu levels in the crop. At site II soil‐Cu was positively correlated with yield and foliar Cu; and negatively with leaf Fe due to a dilution effect. Neither soil Cu nor foliar Cu had any significant effect on Mo in leaves at both sites, except that the increase in yield due to the highest level of Cu at site II was accompanied by an increased plant uptake of Mo. Also, foliar Cu was positively correlated with P, Mg and Mn levels in leaves at site I; and foliar Ca, Mg and Mn at site II.

Residual soil Cu up to 1063 μg.g^‐1 in a mucky peat and 16 59 μg.g^‐1 in a peat showed no signs of causing phytotoxocity or significant nutritional imbalance.     

割面钼磷配施对橡胶树胶乳生理特性的影响

通过在橡胶树割面进行钼磷配施试验，研究了割面施用钼磷营养对胶乳产量和生理参数的影响。结果表明：钼磷配施能够有效影响蔗糖含量、硫醇含量、无机磷含量、镁离子含量、黄色体破裂指数和蔗糖转换酶活性，提高橡胶树的干胶产量。相关分析表明，硫醇含量、蔗糖转化酶活性与干胶产量显著正相关，蔗糖含量与干胶产量为中等程度正相关，无机磷含量、镁离子含量、黄色体破裂指数与干胶产量为负相关。     

Effect of Irrigation Water Contaminated with Uranium Mill Tailings on Sudan Grass,Sorghum vulgare var. sudanense,and Fourwing Saltbush,Atriplex canescens

A greenhouse experiment was carried out to estimate the effects of irrigation water quality on chemical uptake and productivity of Sudan grass (Sorghum vulgare var. sudanense) and fourwing saltbush (Atriplex canescens). Water and soil were obtained from an inactive U ore processing site near Tuba City, Arizona. Two observation wells provided the irrigation water. One was located upgradient from the contaminated site, and was located in the center of the plume downgradient from the area contaminated by the milling operations. A 50/50 mix of the two well waters was used as a third treatment. Concentrations of Se and U in aboveground tissues of saltbush were significantly (< 0.05) elevated when irrigated with the undiluted contaminated water, but not to unacceptable levels. In the case of Sudan grass, Mo, Se, U, NO3 -N, and S were significantly (< 0.05) elevated in the contaminated water treatment, and all except NO3 -N were elevated with the diluted contaminated water, but again within acceptable limits. Saltbush productivity was not significantly (< 0.05) affected by the three irrigation treatments. Sudan grass aboveground biomass results suggest that the undiluted contaminated plume water could be used for effective crop production, although productivity was significantly better with the nutrient-amended baseline water and the diluted contaminated water. Root biomass was significantly greater in the baseline water irrigation.     

Biological nitrogen fixation by common beans (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis> L.) increases with bio-char additions

This study examines the potential, magnitude, and causes of enhanced biological N₂ fixation (BNF) by common beans (Phaseolus vulgaris L.) through bio-char additions (charcoal, biomass-derived black carbon). Bio-char was added at 0, 30, 60, and 90 g kg⁻¹ soil, and BNF was determined using the isotope dilution method after adding ¹⁵N-enriched ammonium sulfate to a Typic Haplustox cropped to a potentially nodulating bean variety (CIAT BAT 477) in comparison to its non-nodulating isoline (BAT 477NN), both inoculated with effective Rhizobium strains. The proportion of fixed N increased from 50% without bio-char additions to 72% with 90 g kg⁻¹ bio-char added. While total N derived from the atmosphere (NdfA) significantly increased by 49 and 78% with 30 and 60 g kg⁻¹ bio-char added to soil, respectively, NdfA decreased to 30% above the control with 90 g kg⁻¹ due to low total biomass production and N uptake. The primary reason for the higher BNF with bio-char additions was the greater B and Mo availability, whereas greater K, Ca, and P availability, as well as higher pH and lower N availability and Al saturation, may have contributed to a lesser extent. Enhanced mycorrhizal infections of roots were not found to contribute to better nutrient uptake and BNF. Bean yield increased by 46% and biomass production by 39% over the control at 90 and 60 g kg⁻¹ bio-char, respectively. However, biomass production and total N uptake decreased when bio-char applications were increased to 90 g kg⁻¹. Soil N uptake by N-fixing beans decreased by 14, 17, and 50% when 30, 60, and 90 g kg⁻¹ bio-char were added to soil, whereas the C/N ratios increased from 16 to 23.7, 28, and 35, respectively. Results demonstrate the potential of bio-char applications to improve N input into agroecosystems while pointing out the needs for long-term field studies to better understand the effects of bio-char on BNF.