Grafting Enhances Copper Tolerance of Cucumber Through Regulating Nutrient Uptake and Antioxidative System

An experiment was carried out to determine plant growth, mineral uptake, lipid peroxidation, antioxidative enzymes, and antioxidant of cucumber plants （Cucumis sativus L. cv. Xintaimici） under copper stress, either ungrafted or grafted onto the rootstock （Cucurbitaficifolia）. Excess Cu inhibited growth, photosynthesis, and pigment synthesis of grafted and ungrafted cucumber seedlings and significantly increased accumulation of Cu in roots besides reducing mineral uptake. Cu concentration in roots of grafted cucumber plants was significantly higher than that of ungrafted plants and obviously lower in leaves. The accumulation of reactive oxygen species （ROS） significantly increased in cucumber leaves under Cu stress and resulted in lipid peroxidation, and the levels of ROS and lipid peroxidation were greatly decreased by grafting. Activities of protective enzymes （superoxide dismutase, SOD; peroxidase, POD; catalase, CAT; ascorbate peroxidase, APX; dehydroascorbate reductase, DHAR; glutathione reductase, GR） and the contents of ascorbate and glutathione in leaves of grafted plants were significantly higher than those of ungrafted plants under Cu stress. Better performance of grafted cucumber plants were attributed to the higher ability of Cu accumulation in their roots, better nutrient status, and the effective scavenging system of ROS.     

关于破解蚕茧交易“瓶颈”的探索

文章介绍了我国茧丝绸产业发展的现状,分析了建立蚕茧生丝拍卖交易平台的必要性和蚕茧拍卖交易的可行性,提出了构建中介拍卖平台,建立公平交易制度,提高茧丝绸产业发展的市场化程度,是破解蚕茧交易"瓶颈",促进产业发展与国际市场接轨的必由之路。     

应用贝叶斯网络模型评价象山港养殖区富营养化风险

为了真实、准确地反映象山港养殖区海域的富营养化状况,以2003—2007年,5年间的象山港养殖区水质监测资料为训练数据并结合有关研究结果,采用K2结构学习算法,构建了基于贝叶斯网络的象山港养殖区水质富营养化风险评价模型,通过该模型得到了各变量间的因果关系及其影响强度。结果表明,试验数据显示准确性为90．18％,Kappa指数为0．8770,以上证明该方法是有效可行的,预测结果表明象山港养殖区水环境富营养化程度日趋严重。     

东北过伐林区蒙古栎天然林土壤有机碳研究

森林土壤有机碳库在维持森林立地生产力以及全球碳平衡过程中起着重要作用。本研究以东北过伐林区蒙古栎天然林为对象,研究不同层次(0~20 cm、20~40 cm和40~60 cm)的土壤有机碳含量和有机碳密度、及其与其他土壤特性的关系。结果表明:(1)蒙古栎林土壤有机碳含量均值为31.48 g.kg-1,0~60 cm土壤剖面有机碳密度为15.76 kg.m-2;土壤有机碳含量和碳密度均随土壤深度增加而显著减少;(2)0~20 cm土层中,除全P和有效P的含量略低,土壤养分含量均较丰富。随着土壤深度的增加,土壤养分含量降低,其在不同土层间的差异显著或极显著(除pH和全K以外),并且土壤养分变异系数均有不同程度的差异;(3)在0~20 cm,土壤有机碳含量和碳密度均与土壤pH呈显著正相关,与土壤全N、全P和速效K呈极显著正相关;就0~60 cm土壤剖面而言,土壤有机碳含量与土壤密度呈显著负相关,土壤有机碳含量和碳密度均与土壤全N、全P、有效P和速效K呈极显著正相关。     

魔芋与玉米间栽对魔芋根际微生物群落代谢功能多样性的影响

研究了魔芋与玉米间栽对魔芋软腐病的控制作用,同时采用Biolog方法间栽对魔芋根际微生物群落代谢功能多样性的影响。结果表明,魔芋与玉米间栽能有效控制魔芋软腐病,其中玉米2∶魔芋4(T3)效果最好,相对防效可达61.27%。另外,魔芋与玉米间栽使魔芋根际微生物Shannon多样性、均匀度指数和每孔颜色平均变化率(AWCD)发生变化,魔芋根际微生物对碳源的利用情况也发生了改变,与净栽魔芋(CK)相比,T3对聚合物类和酚类化合物的利用率分别升高了25.7%和23.5%,而对糖类、羧酸类、氨基酸类和胺类这4类碳源的利用率分别降低了30.7%,39.9%,34.9%和38.6%。主成分分析表明,间栽处理的魔芋根际微生物群落代谢功能与净栽相比差异显著。     

发酵羊肉乳酸菌发酵剂的筛选及发酵性能研究

通过对嗜酸乳杆菌(Lactobacillu acidophilus,简称La),植物乳杆菌(Lactobacillu plantarum,简称Lp),干酪乳杆菌(Lactobacillus casei,简称Lc)进行生化试验,并对其耐食盐、耐亚硝酸盐、产酸能力、生长曲线、抑菌能力及拮抗性能进行试验,从而筛选出适宜于发酵羊肉的优良乳酸菌.结果表明:Lp,La对食盐、亚硝酸盐具有较好的耐受性, 能在6;的NaCl溶液和80～150 mg/kg NaNO2溶液中较好的生长;Lp,La,Lc对蛋白质、脂肪无分解作用,均能抑制大肠杆菌,金黄色葡萄球菌;三株乳酸菌的生长曲线相似,生长2 h可接入羊肉中进行发酵,生长10 h可进入后熟阶段;三株乳酸菌的产酸特性相同,pH值都能在24 h内下降到5.0以下.由于Lp,La拮抗作用弱,所以Lp,La既可单独作为肉制品发酵剂,又可作为混合发酵剂.由于Lc耐盐性和耐亚硝酸盐性差,所以不适于作为发酵肉制品发酵剂.     

贵州省典型铅锌矿区土壤重金属污染状况评价

在贵州DD、DX典型铅锌矿区共采集土壤表层样品27件,针对不同采样点和不同片段的整体研究,采用单因子污染指数法和N.L.Nemerow综合污染指数法对研究区域重金属污染进行研究,结果表明,矿区土壤中重金属污染程度有较大差异,其中Cu、As、Cr等重金属元素无或轻污染;Cd、Zn、Hg、Pb等重金属元素对该区土壤环境已造成污染;2个研究区域土壤中重金属综合污染已相当严重。     

饥饿和再投喂对西伯利亚鲟生化组成的影响

试验设饥饿0、3、6、9、12 d(记为S0(对照)、S3、S6、S9、S12组),然后各恢复投喂20 d,分析了饥饿和再投喂对西伯利亚鲟Acipenser baeri生化组成的影响。结果表明:饥饿结束时,S6和S9组蛋白质含量略高于S0组,S3、S12组略低于S0组,但差异均不显著;除S3组外,各饥饿组脂肪含量均低于对照组,且S6组有显著差异(P<0.05);各组鱼体水分含量有所上升,其中S12组与S0组差异显著(P<0.05)。恢复投喂后,S3、S12组蛋白质含量低于S0组,S6、S9组蛋白质含量高于S0组,但差异均不显著;各组鱼的脂肪含量均升高,但各饥饿组的脂肪含量均低于对照组,且S9组达到显著水平(P<0.05);各组水分含量下降,其中S12组变化显著(P<0.05)。     

银杏胚珠发育及其传粉生物学意义

银杏为雌雄异株、风媒传粉植物。其雌花为裸露的胚珠,胚珠在传粉期不仅负责捕捉和识别空气中漂浮的花粉,而且形成花粉进入胚珠体内的通道和贮存花粉的结构,因此胚珠结构对银杏传粉效率和繁殖成效有重要影响。本文利用半薄切片和扫描电镜等技术观察传粉前后银杏胚珠形态与结构特征的变化,以揭示银杏适应风媒传粉的机制。结果表明:银杏胚珠发育过程中珠柄原基于当年12月首先发生,翌年1月珠被原基分化;3月中旬珠心组织和珠托分化形成,珠心组织分化的同时,周围珠被组织细胞不断分裂增殖,在珠心上方围合形成珠孔道,珠心内则分化形成孢原细胞;3月下旬胚珠珠孔开始开张,珠孔道伸长,珠心组织靠近珠孔端细胞发生解体死亡,贮粉室逐渐形成,孢原细胞逐渐伸长转变为大孢子母细胞;4月上旬,珠孔开张达到最大,并形成向外翻卷的漏斗状,珠孔处产生传粉滴,珠孔道的长度达到最长,贮粉室上方形成开口,大孢子母细胞减数分裂形成四分体,此时为传粉授粉最佳时期;传粉结束后传粉滴消失,珠孔、珠孔道及贮粉室闭合,雌配子体发育进入游离核阶段。以上结果显示经过长期的自然选择与生态演化,银杏胚珠已经具备了许多适应于风媒传粉过程中接受和识别花粉的结构特征。     

Screening for Monoclonal Antibodies Against the Membrane Proteins of Chicken Embryo Fibroblast Blocking the Infection of IBDV

This article aims to establish an efficient assay for screening monoclonal antibodies （McAbs） against the membrane proteins of chicken embryo fibroblast （CEF） for further studies of the cellular receptors of infectious bursal disease virus （IBDV）. McAbs against the membrane proteins of CEF were prepared by cell fusion. The monolayer CEF pre-incubated with the CEF-specific McAbs for 2 h were infected with IBDV and incubated with F22-EA6-biotin postinfection. Then, the cells were reacted with streptavidin-horseradish peroxidase （HRP） and finally stained by 3-amino-9-ethylcarbazole （AEC）. The inhibitive percentage of IBDV infection was calculated by counting the IBDV-infected cells to determine the inhibition efficiency of the CEF-specific McAbs. Compared with the control cells, the IBDV-infected cells pretreated with CEF-specific antibody significantly decreased; supernatant fluids of a total of 768 hybridomas were analyzed. The results of immunohistochemistry assays showed that six of them （1A5, 1H11, 2B 12, 3G1, 4D10, and 4B8） have the abilities to block the infection of IBDV to CEF, among which 4B8 can perfectly block the infection. This novel method is a sensitive and specific assay for the screening of CEF membrane protein-specific McAbs, which can block the infection of IBDV to CEF, and these McAbs can be used for the further investigations of the cellular receptors of IBDV.