可降解水体中烟嘧磺隆微生物的分离与筛选

为了筛选出可降解烟嘧磺隆的微生物,利用富集培养技术从水样中分离得到了5株能以烟嘧磺隆为唯一氮源、碳源和能源的微生物,分别编号为YF1、YB1、YB2、YB3和YB4,其中YF1为真菌,其余均为细菌。将所得菌株定量接种于含不同浓度烟嘧磺隆的培养基中,于30℃、150 r/min摇床上振荡培养5 d后,利用HPLC检测烟嘧磺隆含量,计算降解率。结果发现:这些菌株对低浓度烟嘧磺隆的降解率显著高于对高浓度烟嘧磺隆的降解率,当培养基中烟嘧磺隆的含量为2 mg/kg 时,YF1对该药剂的降解率最高,为80.31 %,其次是YB1和YB2,降解率分别为 78.18% 和73.72%,而YB3和YB4对药剂的降解率只有36.82 %和25.75 %。对3株降解率较高的菌株进行了初步鉴定,发现YF1为黑曲霉Aspergillus niger,YB1和YB2均为芽孢杆菌Bacillus sp.。     

CO2施肥对设施桃树果实性状的影响

以3 a生油桃为试材,在水暖玻璃温室中进行CO2施肥研究.结果表明:CO2施肥可明显提高桃树的光合速率,促进光合产物的合成与积累,提高果实产量和品质.增施CO2后,桃树单株坐果数、单果重量和平均株产均明显提高,维生素C、可溶性固形物、可溶性糖和有机酸的含量以及糖/酸比值都明显上升.     

桂花夏季光合特性及其与环境因子的关系

对盆栽5 a生丹桂的研究结果表明:净光合速率日变化曲线为"双峰"型,光合效率午间明显降低,主要由非气孔限制引起.表观量子效率和实际光化学效率的降低是非气孔限制形成和发展的深层原因.蒸腾速率的日变化为"单峰型",午间最高.利用多元逐步回归方法得到净光合速率和蒸腾速率与环境因子的最优方程,气温和光合有效辐射对净光合速率和蒸腾速率的影响较大.夏季适当遮荫有利于丹桂降低光抑制,提高净光合速率,促进植株生长.     

Effect of environmental enrichment by providing trees as rubbing objects in grassland: Grazing cattle need tree-grooming

We examined the role of trees as grooming objects in grazing pasture and investigated their necessity. Four grazing Japanese Black cows were used. Experimental pastures with restricted (RST) and released (RLS) grooming with trees were established. Examination was carried out for 24 h in each RST and RLS. The respective frequencies and duration of self‐grooming, allo‐grooming (social grooming) and grooming with trees was recorded by a continuous scan sampling method, and maintenance behavior was recorded by a 2‐min group animal scan sampling method. Grooming with trees in RLS occurred 29 ± 12 times/24 h and for 1342 ± 475 s/24 h. Total frequencies and duration of grooming in RLS tended to increase from that in RST (P = 0.08, P = 0.06, respectively). However, self‐grooming and allo‐grooming exhibited no differences. The results indicate that cattle may enrich their grooming through the use of trees if the latter are available. Furthermore, they may not substitute grooming with trees with other forms of grooming if no trees are available in the grassland. No difference was observed in the general proportion of their maintenance behavior. These results suggest that trees in grassland provide a good environmental enrichment object that satisfies cattle's potential needs of grooming and did not restrict their general behavior.     

Cholinesterase (ChE) inhibition in pumpkinseed (Lepomis gibbosus) as environmental biomarker: ChE characterization and potential neurotoxic effects of xenobiotics

Inhibition of cholinesterases (ChEs) has been widely used as an environmental biomarker of exposure to organophosphates (OP) and carbamate (CB) pesticides. More recently, this biomarker has been suggested as a putative biomarker for exposure to detergents. The use of cholinesterase inhibition as effect criterion in Ecotoxicology requires the previous characterization of the specific enzymatic forms that may be present in different tissues or organs. Different ChEs isoforms may be present in the same tissue and may exhibit distinct sensitivities towards environmental contaminants. This work intended to characterize the soluble ChEs present in pumpkinseed sunfish (Lepomis gibbosus) total head and dorsal muscle homogenates, through the use of different substrates and selective inhibitors of cholinesterasic activity. Also, the in vitro effects of sodium dodecylsulphate (SDS - anionic detergent) and chlorfenvinphos (organophosphate pesticide) on the enzymatic activity of the mentioned species were investigated. In general terms, the predominant cholinesterasic form present in both tissues was acetylcholinesterase. Chlorfenvinphos was responsible for inhibitory effects on AChE activity, while SDS did not cause any significant effect. These results suggest that in environmental monitoring programs, L. gibbosus head and dorsal muscle AChE can be an adequate diagnostic tool for exposure to OP pesticides; this conclusion however is not applicable to detergent residues. We also discuss the usefulness of L. gibbosus as an alternative model system and valuable option for freshwater ecotoxicological monitoring programs.     

设施农业土壤磷素富集的动态变化

为了找出设施农业土壤磷素富集的动态变化规律,对陕北地区不同种植年限的设施农业土壤0~40cm土层及剖面磷素含量的动态变化进行了研究。结果表明:土壤全磷、有效磷、无机磷、有机磷含量在不同的种植年限及土层上形成了显著差异,在设施农业环境条件下,长期大量施用磷肥不仅使0~20 cm耕层土壤磷素大量富集,20~40 cm土层磷素也均有不同幅度增加;随着设施农业种植年限的延长,全磷、有效磷和有机磷都以不同的增加幅度和增加量逐年增加,随土层的加深逐渐递减;在各形态无机磷中,Ca2-P、Ca8-P、AL-P、Fe-P、O-P、Ca10-P分别占无机磷总量9.74%、22.18%、6.54%、5.86%、18.02%、37.66%;随着种植年限的延长,Ca2-P、Ca8-P、AL-P、Fe-P、O-P、Ca10-P含量都有不同程度的富集,主要以磷酸钙盐(包括Ca8-P、Ca10-P、Ca2-P型)的形态积累在不同土层中。     

干旱区绿洲土壤中Ni在芹菜中的富集迁移

以干旱区绿洲土壤为供试土壤,采用盆栽试验研究外源Ni污染对芹菜生长的影响及在芹菜中的富集迁移。结果表明：外源Ni的添加在低质量分数下能够促进芹菜的生长,达到一定临界值后,则出现明显的毒害作用;随着土壤中Ni的添加质量分数的增加,芹菜体内的Ni含量也随之增加。统计分析表明对芹菜根部和地上部吸收累积Ni贡献最大的均为铁锰氧...     

环境丰容在鹦鹉展区中的应用

2007年12月～2008年8月,通过进行笼内环境生态化布置、改变食物投喂方式、投放玩具等方式,对上海动物园葵花凤头鹦鹉实施了丰容试验,并通过对3只葵花凤头鹦鹉的行为观察进行了丰容效果的评价。结果表明：丰容促进了鹦鹉身体各部位协调性;休息行为减少,活动行为增加;异常行为减少;丰容区域利用率大于非丰容区。针对动物园鹦鹉饲养中存在的一些问题,本文提出了几点建议：保证视线无障碍设施的防撞、防逃逸、通风、保洁＇加强饲养员的专业知识培训和责任性教育i针对不同物种采取不同丰容方式并定期维护及更换丰容设施;经常开展国际交流,提升丰容水平等。     

春季某牛场奶牛乳房炎与环境中主要致病菌相关性研究

本试验根据锡林浩特市某奶牛场临床型或隐性乳房炎的发病情况,采集47份乳样、35份环境样品,进行细菌分离鉴定、并对其主要病原菌进行药敏试验。从乳样中分离出13种细菌共81株,从环境样中分离出主要致病菌6种34株。选择27种抗生素对主要致病菌进行药物敏感性试验,结果表明,乳样和环境中的致病菌都对头孢菌素类、喹诺酮类药物较为敏感。乳样中的致病菌对青霉素、链霉素及磺胺类等药物均产生不同程度的耐药性,而环境中主要致病菌对青霉素G、新生霉素、氨苄西林表现出具有耐药性。对乳样中分离得到细菌和相应环境分离得到的细菌进行对比分析．发现两者药物敏感性和耐药性方面存在一定的相关性。     

氮肥的环境风险及管理研究进展

氮肥的施用在农业生产和产量增加上具有重要作用.然而,自从20世纪90年代以来,投入到农业生态系统中的氮肥已经成为氮素的重要污染源.低的氮肥利用率伴随着高的环境污染是世界范围内氮肥使用中普遍存在的现象.过度的氮肥使用已经对空气、土壤和水体等环境造成了严重污染,同时也在很大程度上扰乱了全球的生物地球化学循环,导致了生物多样...