钙盐诱导下土壤锰和铁的释放及其对胡椒的生物有效性

Releases of manganese and iron ions from an albic soil (Albic-Udic Luvisol), a yellow-red soil (Hap-Udic Ferrisol) and a yellow-brown soil (Arp-Udic Luvisol) induced by calcium salt addition and their bioavailability to pepper (Capsicum frutescens L.) were studied in a pot experiment. Addition of Ca(NO₃)₂ decreased soil pH and increased both exchangeable and DTPA (diethylenetriamine pentaacetic acid)-extractable Mn and Fe in soils. Meanwhile, total Mn accumulation in the shoots of Capsicum frutescens L. on the salt-treated soils increased significantly (P< 0.01) compared with the control, suggesting that salt addition to soil induced Mn toxicity in Capsicum frutescens L. Although exchangeable and DTPA-extractable Fe increased also in the salt-treated soils, Fe uptake by the shoots of Capsicum frutescens L. decreased. The effect of added salts in soils on dry matter weight of pepper varied with the soil characteristics, showing different buffer capacities of the soils for salt toxicity in an order of yellow-brown soil > albic soil > yellow-red soil. Fe/Mn ratio in shoots of Capsicum frutescens L. decreased with increasing salt addition for all the soils, which was ascribed to the antagonistic effect of Mn on Fe accumulation. The ratio of Fe/Mn in the tissue was a better indicator of the appearance of Mn toxicity symptoms than Mn concentration alone.     

海绵铁内电解法处理染整废水的研究

采用烧杯试验法对羊绒制品染整废水进行海绵铁内电解法去除色度及化学需氧量(COD)的试验研究。试验结果表明,海绵铁投加量在500 g/L、pH 5～6、反应时间为60 min,在一定的搅拌强度下辅以混凝、氯氧化综合作用,色度的去除率达到90%以上、COD的去除率达到95%以上,废水出水能达到国家标准。     

电场驱动纳米Fe0在不同介质中的迁移行为研究

选取四种不同介质(100%石英砂、75%石英砂/25%高岭土、50%石英砂/50%高岭土和100%高岭土),探讨了黄原胶分散的纳米Fe~0在不同介质中的迁移行为。纳米材料投加点设置在介质填充池中间靠近阳极电解池的位置。研究发现,采用该实验装置,100%石英砂的处理中电渗流量最大,这与其较大的孔隙和渗透性有关,加入高岭土的处理中电渗流量较小且各处理流量相当。纳米Fe~0在石英砂中的迁移高于加入高岭土的处理,大部分纳米Fe~0集聚在靠近投加口的部分,在远离投加口的部分铁逐渐由Fe2+向Fe3+转化。100%高岭土中纳米Fe~0的迁移高于混合介质处理,这与其较高的电流强度有关。纳米Fe~0在电动迁移过程中很容易发生溶解和转化,其在高岭土中的迁移是以离子态进行的。μ-XANES(微束X射线近边分析)的分析结果证实电场驱动下高岭土中的铁主要以纤铁矿和磁铁矿形式存在。     

硫酸亚铁诱导根表铁膜形成对水稻吸收和转运铜锌的影响

通过水培条件下添加硫酸亚铁诱导水稻根表铁膜的形成,利用连二亚硫酸钠-柠檬酸钠-碳酸氢钠(DCB)溶液对根表铁膜进行提取后测定,采用扫描电镜-能谱仪(SEM-EDS)和X射线衍射仪(XRD)等手段对硫酸亚铁诱导产生的根表铁膜进行表征,并分析根表铁膜对水稻吸收铜锌的影响。结果表明,添加硫酸亚铁可以诱导根表铁膜在水稻根系表面产生,未处理的水稻根表Fe含量为731 mg·kg~(-1),80 mg·kg~(-1) Fe~(2+)处理下水稻根表Fe含量为53 562 mg·kg~(-1);SEM-EDS和XRD分析发现大量颗粒状含铁化合物附着于水稻根表。与未经硫酸亚铁处理相比,有根表铁膜水稻的铁膜中,其Cu含量最高增加73.16%,Zn含量最高增加112.10%;水稻根系Cu含量最高降低31.15%,Zn含量最高降低13.02%;水稻茎叶Cu含量最高降低19.50%,Zn含量最高降低25.56%。土壤添加硫酸亚铁可以显著降低水稻对Cu和Zn的吸收与积累。     

Iron Sources Effects on Growth,Physiological Parameters and Nutrition of Cacao

Productivity and sustainability of cacao (Theobroma cacao L.) in tropical soils are affected by levels of iron. Information is lacking on the cacao response to various sources of iron (Fe). A greenhouse experiment was conducted to evaluate the effects of five iron sources iron sulfate heptahydrate, ferric ethylenediamine-N,N’-bis(2-hydroxyphenylacetic acid), ferric diethylenetriaminepentaacetic acid, ferric ethylenediaminetetraacetic acid, fiesta herbicide (FeSO₄ · 7H₂O, FeEDDHA, FeDTPA, FeEDTA,) at 10 mg Fe kg^?1 soil on growth, photosynthesis, content of photosynthetic pigments and starch and macro- and micronutrient nutrition of cacao. The various iron sources had significant effects on shoot and root dry biomass accumulation, leaf chlorophyll a and b content, carotenoid levels, SPAD index and P_N. These parameters were significantly correlated with concentration, uptake, influx, and transport and use efficiency of Fe. In cacao net photosynthesis, stomatal conductance, internal carbon dioxide (CO₂)_, and transpiration in leaf level responded differently to the sources of Fe. Invariably, macro and micronutrient uptake, influx, transport, and use efficiency showed differential responses to sources of iron but significant effects were only observed for copper (Cu), Fe, manganese (Mn), and zinc (Zn). Overall, FeDTPA, FeEDTA and FeHEDTA could be the best sources of Fe in improving, growth, photosynthesis and macro and micro nutrition of cacao.     

温度对酸性草酸-草酸铵溶液浸提土壤无定形铁的影响

以下蜀黄土为试材,研究温度对酸性草酸-草酸铵缓冲溶液浸提土壤无定形铁的影响。结果表明:随着浸提温度的升高,铁的浸提量明显增加。30℃浸提出的铁约为20℃的1.57倍;而50℃浸提出的铁约为20℃的4.43倍。随温度的升高,浸提后土壤残渣的磁化率迅速降低。20℃浸提后残渣的磁化率值比原样略有减少;30℃浸提后残渣的磁化率约为原样的93.6%;50℃浸提后残渣的磁化率只有原样的65.3%。这说明随着温度的升高,以磁性矿物为代表的结晶态铁也被溶解,浸提出的铁其实已不仅是无定形铁。因此,用酸性草酸铵浸提无定形铁时,严格控制20℃的反应温度十分关键。     

富铁水稻研究进展

本文简述了水稻品种间铁含量的差异性及其遗传控制,综述了采取提高铁绝对含量及增加其生物有效性开展富铁水稻的研究进展,包括常规育种、诱变育种、转基因技术。对富铁水稻研究中存在的问题及诱变技术在该方面的应用前景也作了探讨。     

丛枝菌根真菌对枳不同根围铁及球囊霉素螯合金属的影响

采用盆栽根袋技术,将枳根围土壤分为0-2、2-4和4-8 cm 3个水平土层,研究丛枝菌根(AM)真菌地表球囊霉对枳根围土壤中有效Fe及球囊霉素鳌合金属含量的影响.结果表明,接种AM真菌显著降低了枳根围土壤中有效Fe的含量.接种AM真菌的土壤有效Fe含量表现为:0-2 cm2-4 cm4-8 cm,而未接种的则表现为:4-8 cm2-4 cm0-2cm;枳不同根围土壤中的菌丝密度表现为:0-2 cm2-4 cm4-8 cm,表明菌丝能够穿过尼龙网伸展到4-8 cm土层中;枳不同根围土壤中易提取球囊霉素和总球囊霉素的变化规律一致,表现为:2-4 cm4-8 cm0-2 cm;土壤中球囊霉素螯合Fe和Mn的含量在4-8 cm土层中最少,螯合Zn和Cu的含量则在0-2 cm土层中最少.可见,球囊霉素能够螯合Cu等元素,减轻土壤中重金属元素对AM真菌的威胁,进而起到缓冲金属元素释放和保护真菌的作用.     

小麦根系在不同铁营养水平条件下的蛋白质组差异表达分析

为了探究小麦根际不同铁水平对根系基因表达的调控,采用小麦‘北农9549’为材料,进行缺铁胁迫和胁迫后恢复铁供应等不同处理,用双向电泳的方法分离蛋白,对比分析不同处理间根系蛋白质表达的差异。结果表明,缺铁处理植株与正常供铁的植株相比,缺铁条件下生长的小麦根系有137个蛋白点的表达水平变化具有显著差异（P<0.05）,其中76个蛋白点发生大于2倍的显著上调表达,另有61个蛋白点发生大于2倍的显著下调表达。上述经过铁饥饿的小麦根系恢复正常铁供应2周后,与自始至终正常供铁的根系相比,有150个蛋白点的表达水平变化具有显著差异（P <0.05）,其中78个蛋白点发生大于2倍的显著上调表达,另有72个蛋白点发生大于2倍的显著下调表达,本试验结果表明,缺铁会引起小麦根系表达大量特异性蛋白。     

The response of normal and iron anemic calves to nasal infection with an attenuated strain of parainfluenza-3 virus.

Calves with experimentally induced iron deficiency anemia and normal calves, both groups deprived of colostrum, were exposed to intranasal instillation of an attenuated parainfluenza-3 virus strain.The calves became infected, but there was no difference in the clinical picture between the 2 groups of calves. Neither was there a difference in the humoral or local immune response to parainfluenza-3 virus.