Fate of Zinc Ammonia Acetate in Soils and Its Uptake by Corn

Zinc ammonium acetate (ZAA) is applied to soil with anhydrous ammonia as a carrier to improve corn (Zea mays L.) productivity. To study the fate of ZAA in the soils, a laboratory leaching experiment was conducted with ¹⁴C-ZAA and ⁶⁵Zn-ZAA using water or NH₄OH as carrier. Results showed that ZAA degraded in the soil and released CO₂. The released CO₂ was from the acetate component of ZAA and accounted for less than 0.06% of the total applied ¹⁴C. Using H₂O as carrier resulted in more CO₂ release than using NH₄OH, regardless of soil type. However, more ¹⁴C was detected in the leachate when using NH₄OH as a carrier than when using H₂O. A plant uptake experiment using ¹⁴C-ZAA and ⁶⁵Zn-ZAA indicated that four-leaf-stage corn seedlings absorbed higher amounts of ¹⁴C in the stem and root than in the leaves. The ⁶⁵Zn was detected in most tested plant parts. Our study showed that ZAA enhanced cytokinin levels in root and/or shoot tissues of corn seedlings, suggesting a secondary regulatory effect of ZAA in improving corn productivity.     

NaOH水溶液提取穿心莲内酯工艺研究

[目的]探索低成本高含量的穿心莲内酯的提取工艺。[方法]以穿心莲茎叶为材料,粉碎后在不同pH值的NaOH溶液中,利用超声波法提取穿心莲内酯。测定了提取的浸膏中穿心莲内酯的含量和回收率。[结果]NaOH溶液的pH值为7.5时,穿心莲内酯浸膏的得率最低,为3.57%,浸膏中穿心莲内酯的含量最高,为9.5000%。当NaOH溶液的pH值为9.5时,穿心莲内酯浸膏的得率最高,为6.71%,浸膏中穿心莲内酯的含量最低,为0.0190%。该检测方法的平均回收率为99.9%。[结论]pH值为7.5的NaOH溶液中,超声波法提取的穿心莲内酯总量最多 在pH值为9.5的NaOH溶液中提取的穿心莲内酯总量最少。     

磷化氢熏杀其抗性害虫实仓试验

用磷化铝片对储藏在房式仓（仓容５１６ｍ３）中的４００ｔ散装小麦进行熏蒸。储 不小麦水分为１１．５％,储藏平均温度为２９．３℃,小麦用ＰＶＣ（厚度０．１２５ｍｍ）复盖。熏 蒸期间用磷化氢检测管测定ＰＨ3浓度。采用１．０３ｋｇ磷化铝片（可释放０．３４ｋｇ磷化氢） 分成小包进行熏蒸,磷化氢最高值为 １． ０ｍｇ／Ｌ。熏蒸 １６天的 ＣＴ值为 ２１３ｍｇ· ｈ／Ｌ。用 敏感和抗性品系的米象和谷蠹进行生物试验表明．熏蒸１个月后所有的成虫都死亡;熏 蒸４２天所有中度抗性的谷蠹没有发现Ｆ１代成虫出现．米象的印和蛹不能发育为成虫。     

尿素和氢氧化钙处理玉米秸对体外瘤胃内环境的影响

为了研究尿素和氢氧化钙处理玉米秸对体外瘤胃内环境的影响,采用2因素3水平完全交叉试验设计,将尿素和氢氧化钙均按玉米秸干物质质量的2%、3%和4%的量分别添加,共9个试验组和1个对照组(添加量为0),通过短期人工瘤胃技术研究不同水平尿素和氢氧化钙处理玉米秸对瘤胃液pH值、氨氮(NH3-N)质量浓度、微生物蛋白(MCP)产量和挥发性脂肪酸(VFA)浓度的影响。结果表明,不同水平尿素和氢氧化钙处理玉米秸对瘤胃液pH值影响不显著(P>0.05);对氨氮质量浓度影响显著或极显著(P<0.05或P<0.01),但均在正常范围内;在MCP产量方面,第6、7、8组和第10组极显著高于对照、第2、3、4组和第9组(P<0.01),分别比对照组高26.74%、27.91%、36.05%和32.56%,第7、8组和第10组3个组间无显著差异(P>0.05),第8组和第10组显著高于第5组和第6组(P<0.05),第7组和第5、6组间无显著差异(P>0.05);第10组的乙酸、丙酸和丁酸3种挥发性脂肪酸总浓度极显著高于对照组(P<0.01),比对照组高84.59%,第10组极显著或显著高于其他试验组(P<0.01或P<0.05)。结果显示,第10组即尿素和氢氧化钙处理玉米秸时,添加水平均为其干物质量的4%是最适宜的。     

Forest drainage: a threat to benthic biodiversity of boreal headwater streams?

1. Forest drainage, including mainly ditching of waterlogged peatlands in order to increase wood growth, has caused substantial changes in the hydrology and water quality of Finnish streams. However, knowledge on the ecological impact of these changes is poor. This paper studies the potential impact of forest drainage, catchment characteristics and habitat factors on the water quality and benthic macroinvertebrates in headwater streams of the River Isojoki, western Finland. An intensive programme of water sampling was carried out at nine study sites, while zoobenthic samples covered a total of 18 streams. 2. According to multivariate regression models concentrations of aluminium and suspended solids in stream water at nine study sites increased significantly with increasing forest drainage of the catchment area. Further, drainage intensity contributed significantly to the decrease in minimum values of alkalinity. 3. In a Canonical Correspondence Analysis, the variation in macroinvertebrate species distribution and abundance was largely explained by drainage intensity, moss coverage and the concentrations of aluminium and iron in stream water. A significant positive correlation was established between the species richness of benthic macroinvertebrates and the proportional cover of vegetation on the stream bed, whereas a significant negative correlation was found between species richness and sand cover. 4. The results suggest that drainage has significantly contributed to the deterioration of water quality and habitat structure, and impoverishment of benthic communities in the headwater streams of the River Isojoki. In order to protect the ecological integrity of such boreal headwater streams, more effective protection schemes in forestry practices and rehabilitation of the adversely affected streams and their catchment areas are needed. © 1998 John Wiley & Sons, Ltd.     

铝处理对2个桉树无性系幼苗丙二醛含量的影响

采用室内水培试验法,研究了铝处理对广西区2个优良桉树无性系(Eucalyptus grandis×E.urophylla No.9和E.urophylla No.4,分别记为G9、G4)根系及叶片内MDA含量的影响。结果表明:2个桉树无性系根内MDA含量均比叶内高;铝处理下,2个桉树无性系幼苗的MDA含量明显升高,G4根中MDA含量最高,达11.49μmol·g-1,根中MDA含量比叶中高,桉树无性系幼苗根部受铝伤害较叶严重。     

水化氯铝酸钙与传统钝化剂降低土壤镉生态及健康风险的对比研究

针对红壤、棕壤、褐土、黑土4种中国典型的Cd污染土壤,应用Ca(OH)2、Ca(H2PO4)2以及层状双金属氢氧化物（Layered Double Hydroxides,LDHs）、水化氯铝酸钙（CaAl-Cl LDH）开展钝化修复,并从土壤Cd的生态风险和健康风险角度进行修复效果对比研究。分析钝化剂对土壤pH值、土壤Cd的赋存形态以及土壤Cd直接经口摄入的生物可给性的影响,并对修复机理进行深入探究。结果表明,在Ca(OH)2、Ca(H2PO4)2和CaAl-Cl LDH各自相对最优施用量下,3种钝化剂均可显著降低土壤Cd的活性系数（P<0.05）,平均降幅分别为16.1%、56.9%和29.2%,可降低土壤Cd的作物吸收量及Cd对周边生态环境的风险。此外,施用CaAl-Cl LDH能显著且更为有效地降低土壤Cd的生物可给性（P<0.05）及Cd对人体的健康风险,在胃和小肠阶段的平均降幅为19.2%和33.0%,其中胃阶段分别达到施用Ca(OH)2和Ca(H2PO4)2的3.11和1.99倍,小肠阶段为5.99和2.72倍。该研究为Cd污染土壤钝化修复剂的开发、改进和选择提供了科学依据和参考。     

用氟离子电极法测定土壤中铝

本文提出了用氟离子电极法来测定土壤中铝的实验方法。根据“氟、铝离子浓度相关表”由测得的游离态F-浓度即可查得铝的总浓度C_(A1),从而求得土壤中的铝含量。     

乳制品中金黄色葡萄球菌PCR快速检测方法的建立

为快速检测乳制品中的金黄色葡萄球菌,本研究将纳米氢氧化钛和纳米氢氧化锆固定在滤纸片上以去除PCR反应抑制因子,并以Nuc为靶基因,建立一种无需样品前增菌的PCR快速检测方法,同时确定该方法的特异性、灵敏度和实用性,并评估该方法所用试剂在冷冻保存条件下的稳定性与实用性。结果表明,该PCR快速检测方法在检测97株目标菌及83株非目标菌后未出现假阳性或假阴性结果;该方法无需增菌处理,可在4 h内完成检测,检测限为10¹ CFU·25 g^-1或10¹ CFU·25 mL^-1;该方法与传统检测方法在实际乳制品样品中金黄色葡萄球菌的检出率及活菌检测率均一致(符合率100%);此外,该检测方法所用试剂在-20℃冷冻条件下可稳定保存至少12个月。综上所述,本研究建立的PCR快速检测方法特异性强、灵敏度高,且实用性良好,能有效去除样品基质中的PCR反应抑制因子,为乳制品中金黄色葡萄球菌的快速检测提供了参考依据。     

壳寡糖及其复合聚合氯化铝絮凝微藻富集的研究

［目的］ 为了找到可以加速微藻富集的合适絮凝剂。［方法］ 制备了壳聚糖的降解产物壳寡糖,用于绿色巴夫藻（Pavlovaviridis Tseng, Chen et Zhang）和小球藻（Chloreiia spp.） 絮凝富集。［结果］ 终浓度为30 mg/L以上的壳寡糖溶液对2种藻类具有显著的促沉降效应。当壳寡糖与6 mg/L聚合氯化铝混合使用时,壳寡糖/聚合氯化铝促沉降效应明显提高。［结论］ 壳寡糖可以用于微藻大规模生产的采收。