地表臭氧浓度升高对旱作农田N2O排放的影响

通过田间试验,在冬小麦和大豆生长季设置3种不同臭氧(O3)浓度的处理,包括自由空气(对照,CK)、100 n L·L-1O3浓度(T1)和150 n L·L-1O3浓度(T2),采用静态箱-气相色谱法测定N2O排放通量,研究地表O3浓度升高对冬小麦-大豆轮作系统N2O排放的影响.结果表明,与CK相比,在冬小麦返青期,T1和T2处理都降低了土壤-冬小麦系统N2O累积排放量,降幅分别为37.8%(P=0.000)和8.8%(P=0.903);在拔节-孕穗期,T1和T2处理使N2O累积排放量分别降低了15.0%(P=0.217)和39.1%(P=0.000);从冬小麦全生育期来看,T1、T2的N2O累积排放量分别降低了18.9%(P=0.138)和25.6%(P=0.000).由于本年度大豆生长季降水偏少,受干旱胁迫的影响,O3浓度升高对大豆田N2O排放的作用不明显.本研究表明地表O3浓度升高会减少旱作农田N2O排放量.     

东北春大豆品种东生1号对臭氧胁迫的响应

采用开顶式气室(OTCs)方法,研究了不同臭氧(O3)浓度处理对春大豆品种"东生1号"的影响,主要包括产量与产量构成因子,叶片与籽粒碳、氮元素与碳氮比、盛花期叶片气体交换速率、叶绿素荧光参数与光合色素含量变化.试验设置3个臭氧水平:过滤大气(CFA,10 nL·L-1)、自然大气(NFA)与自然大气添加40 nL·L-1(NFA+O3).结果表明,经过一个生长季处理(AOT40值累积为10.6μL·L-1·h),与CFA相比,NFA处理东生1号大豆单株产量与百粒重降低4.5%、4%,而NFA+O3处理分别显著降低34%、18%(P<0.05),而处理间株高、主茎节数、单株荚数与每荚粒数均无显著变化.鼓粒期NFA+O3处理叶片C、N元素含量分别显著增加3%、26%,碳氮比则显著降低18%.CFA与NFA相比,NFA+O3显著降低盛花期大豆叶片净光合速率(Asat)、气孔导度(gs)、水分利用效率(WUE)、开放的光系统反应中心激发能捕获效率(F’v/F’m)和作用光下光系统Ⅱ的实际量子效率(ΦPSⅡ),而胞间CO2浓度(ci)、光化学猝灭系数(qP)和光合色素含量则无显著变化.结果表明,O3浓度升高导致东生1号单株产量下降的主要原因是其显著降低百粒重、净光合速率和电子传递效率.     

油母页岩废渣对大豆产量影响分析

通过实验研究了施用油母页岩废渣对大豆产量的影响,试验结果表明,施用油母页岩废渣能促进大豆生长发育,显著提高大豆产量,其中,中量油母页岩废渣21t/hm2·a配施氮磷钾化肥的效果最好,其增产率达184.03%,但随着油母页岩施用量的增加,其增产效果下降。     

大豆和小麦根系对菲的吸持作用及其生物有效性

不同作物根系对多环芳烃(PAHs)的吸持作用及其生物有效性研究有助于深入揭示PAHs在生态系统中的环境行为和科学评估PAHs的生态风险.然而,不同作物根系吸持PAHs的差异性及其生物有效性鲜有报道.为此,本研究以菲作为PAHs的代表,探究了不同条件下大豆和小麦根系对菲的吸持/解吸及其吸持菲的有效性.结果表明,根系菲吸持随时间的变化表现为:活体根处理先增加再降低而后趋于平衡,这与活体根系存在菲转运延迟有关;灭活根和烘干根处理则先增加而后趋于平衡.根系的比表面积越大,脂肪含量越高,菲的吸持速率越快.不同菲浓度条件下,各处理根系菲的吸持量均随平衡浓度的增加而增大,Henry吸附等温式拟合R2均大于0.973,灭活根和烘干根用Freundlich吸附等温式拟合效果更好,小麦根系的Langmuir吸附等温式拟合效果优于大豆根系,说明分配作用和表面吸附共同控制作物根系菲的吸持,而活体根系与菲存在特殊的键合作用,其拟合效果较差.脂肪含量越高、含水率越高、膜的通透性越大,根系的吸持容量也越大.吸持在根系上的菲的解吸率的大小顺序为活体根烘干根灭活根;大豆各处理根系小于相应的小麦根系.不同根系吸持菲的生物有效性与解吸结果一致,因此可以用解吸率评价其生物有效性.研究结果可为作物根系吸持PAHs的当季和后茬作物有效性评估提供依据.     

New technique using galactose-specific lectin for isolation of fetal cells from maternal blood

To isolate fetal cells from maternal blood, we developed a new method based on galactose-bearing conjugation. Nucleated red blood cells (NRBCs), which highly express galactose on their surface, were selectively attached to a substrate coated with a galactose-containing polymer via soybean agglutinin (SBA), a galactose-specific lectin. Cord blood samples were used to evaluate enrichment efficacy of NRBCs by this method. Blood samples were obtained from 131 pregnant women between 6 and 27 gestational weeks. After preliminary condensation of fetal cells by Ficoll gradient centrifugation, NRBCs were enriched using galactose-positive selection by adjusting SBA concentration. We isolated one to severalhundred NRBCs (mean±SD, 7.8±8.5) in 2.3 ml of peripheral blood samples from 96% of pregnantwomen. The isolated NRBCs were analyzed by a Y-chromosome FISH probe in eight cases carrying male fetuses. Y-signals were detected in all eight cases and more than half of the NRBCs wereoffetal origin. The study demonstrates that our new method using galactose-specific lectin provides effective enrichment of fetal NRBCs allowing non-invasive prenatal diagnosis. Copyright © 2002 John Wiley & Sons, Ltd.     

聚乙烯与磺胺二甲嘧啶复合胁迫对大豆种子萌发及幼苗生长生理特征的影响

土壤环境中微塑料吸附抗生素产生复合污染已不可避免,但二者复合胁迫下的植物生物效应尚不清楚.以大豆品种晋豆21号为试材,采用种子萌发试验和幼苗盆栽试验研究聚乙烯（PE）和磺胺二甲嘧啶（SMZ）不同单一及复合处理对大豆种子萌发、幼苗生长、光合参数、叶绿素荧光参数和氮代谢的影响.结果表明,单一PE处理对大豆种子萌发和幼苗生长生理的影响总体表现为"低促高抑"的规律,较低水平PE［10 mg ·L^-1（或mg ·kg^-1）］处理对大豆种子萌发、幼苗生长、光合作用和氮代谢有促进作用,但较高水平PE［100 mg ·L^-1和200 mg ·L^-1（或mg ·kg^-1）］的抑制作用显著;单一SMZ处理对大豆种子萌发和幼苗生长生理产生不同程度的抑制作用,且抑制程度随着SMZ处理水平的增加呈升高趋势.不同水平PE和SMZ复合处理下,较低水平PE的加入能够缓解单一SMZ处理对大豆的抑制作用,以10 mg ·L^-1（或mg ·kg^-1） PE+1 mg ·L^-1（或mg ·kg^-1） SMZ处理的综合缓解效果最佳,具体表现为较单一SMZ处理增加了大豆种子发芽势、发芽率、发芽指数、活力指数、株高、根长、地上部及根部鲜重、P_n、G_s、T_r、叶绿素含量、F_v/F_m、Φ_PSⅡ、ETR、qP和NR等氮代谢关键酶活性,降低了种子平均发芽时间、C_i、NPQ、NO₃^--N和NH₄⁺-N含量;而较高水平PE的加入增强了SMZ处理对大豆的抑制作用,且抑制程度随着SMZ处理水平的增加呈升高趋势,其中200 mg ·L^-1（或mg ·kg^-1） PE+50 mg ·L^-1（或mg ·kg^-1） SMZ处理的抑制程度最大.综上可知,低水平PE能够一定程度缓解单一SMZ胁迫对大豆种子和幼苗的抑制作用,而高水平PE的加入则与SMZ产生协同作用,加剧了单一胁迫处理的毒害效应.     

Impacts of the deforestation driven by agribusiness on urban population and economic activity in the Dry Chaco of Argentina

Agriculture expansion oriented to global market has changed the relation between population and deforestation in South America. Actually, the population dynamic in an agricultural frontier turned into a consequence of deforestation (rather than the cause). For Dry Chaco of Argentina during the period 1991–2001, we explore the impacts of deforestation over urban population and employment dynamics in small- and medium-size urban centers. We used deforestation maps from remote sensing data and demographic information from the national census. We found a positive relation between population growth and deforestation. Additionally, urban centers in a context of new and active deforestation stages generate more jobs than in a context of advanced stages. Based on our results, we suggest a boom and bust pattern. Agriculture expansion and deforestation generate transient jobs and benefits, but in a long-run perspective, positive impacts are uncertain.     

Protoplast fusion between Saccharomyces cerevisiae and Rhodobacter sphaeroides for the treatment of soybean wastewater

The kinetic parameters and the purification rates of the hybrid cell Foaz in soybean processing wastewater (SPW) were measured through a shaking reaction and in two automatic regulated control stable fermentation systems (ARCSFS). The maximum specific growth rate of Foaz was 0.576 h^‐1, higher than that of one of its parental strains Rhodobacter sphaeroides P9479 and lower than that of another parental strain Saccharomyces cerevisiae Y9407. The BOD₅ removal rate of Foaz in the No. 1 system was 61.3%, higher than those of both its parental strains when the influent BOD₅ concentration was 4600 mg/L. The results of this study suggest that the hybrid Foaz has a better capacity of the degradation of organic pollutants in SPW than its parental strains and it may be applicable to the treatment of high concentration organic wastewater.     

苗期玉米、大豆在土壤-植物系统N2O排放中的贡献

为区分植物在土壤-植物系统N₂O排放中的贡献,用封闭式箱法对在温室内砂培和土培的玉米、大豆幼苗及砂、土、砂-植物系统、土壤-植物系统的N2O排放进行了测定,同时对植物N₂O排放与植物叶片中的硝酸还原酶(NR)活性及NO₃^--N、NO₂^--N含量的关系进行了分析.结果表明:在53d的观测期内,玉米、大豆幼苗本身均可排放N₂O,且在土壤(砂)-植物系统的N₂O排放中占有很大份额(79.18%～100%);植物N₂O的排放与植物叶片的硝酸还原酶活性和NO₃^--N、NO₂^--N的含量显著正相关(R²≥0.97,n=6).     

Biodegradation Behavior of Some Vegetable Oil-Based Polymers

The potential biodegradability of several vegetable oil-based polymers was assessed by respirometry in soil for 60–100 days at temperatures of 30–58°C. Films of soybean oil and linseed oil which were oxidatively polymerized (Co catalyst) on a kraft paper support were 90%–100% mineralized to CO₂ after 70 days at 30°C. Mineralization of polymerized tung oil to CO₂ was much slower than soy or linseed oils. Mineralization of epoxy resins made from epoxidized soybean oil (ESO) and aliphatic dicarboxylic acids was rapid while mineralization of similar resins made with a triacid (citric) was slower. There was no significant degradation of polyamine/ESO resins after 100 days at 58°C. Mineralization of the available carbon in vegetable oil polyurethanes and cationically polymerized ESO was less than 7.5% after 70 days at 30°C and 25 days at 55°C compared to 100% for soybean oil. From these results, it appears that triglycerides highly cross-linked with non-degradable linkages are not biodegradable to a significant extent while triglycerides cross-linked with hydrolysable bonds such as esters remain biodegradable.