李的大小孢子及雌雄配子体发育研究

以牛心李（ＰｒｕｎｕｓａｍｅｒｉｃａｎａＭａｒｓｈ）为材料，系统地观察了李的大小孢子与雌雄配子体发育，结果表明：①３月末～４月末为小孢子及雄配子体发育时期。小孢子母细胞减数分裂中，胞质分裂为同时型，呈四面体型排列，成熟花粉为２—细胞型，②４月中旬～５月初，为大孢子和雌配子体发育时期。双珠被、厚珠心，胚囊发育属单孢子蓼型。并对其发育的时序性、地域性等问题进行了讨论。     

Chlorophyll meter predicts nitrogen status of tall fescue

The nitrogen (N) status of a crop can be used to predict yield and supplemental N fertilizer requirements, and rapid techniques for evaluating the N status of crops are needed. A study was conducted to determine the feasibility of using a hand held chlorophyll meter (SPAD 502, Minolta Co. Ltd., Japan) to monitor N status of tall fescue (Festuca arundinacea Schreb.). Four diverse tall fescue genotypes were grown at three locations in Alabama and fertilized at four N‐rates from 0 to 336 kg ha^‐1. A similar experiment was conducted in the greenhouse using soil from the same field sites. Chlorophyll meter readings (SPAD) were taken, and extractable chlorophyll content, tissue N concentration and dry matter yield were determined at harvest. SPAD, extractable chlorophyll content, tissue N concentration, and dry matter yield increased quadratically (0.67 < R² < 0.99) with increasing N fertilization in both experiments. All genotypes responded similarly to applied N, with some differences in magnitude. Relationships between SPAD meter readings and extractable chlorophyll and tissue N concentrations were linear with r² > 0.95. An additional independent variable, the square root of the inverse of SPAD, lowered the residual mean square by 11 and 16%, respectively, for tissue‐N and chlorophyll concentrations, but did not increase the R². This would be preferred for predictive purposes. Tissue N concentrations at higher N‐rates were sufficient for maximum yield which occurred at 290 and 248 kg N ha^‐1 for greenhouse and field, respectively, but were lower than previously reported sufficiency values. The chlorophyll meter is an easy and efficient method of detecting tall fescue N status.     

美洲大蠊雌成虫混配饲料的优化配方

采用正交试验设计L9(34)的方法,研究了小麦粉、奶粉、干酵母粉等3种饲料成分对美洲大蠊雌成虫取食和生殖的影响.结果表明:以美洲大蠊的产卵荚量为指标,3个组分的影响由大至小依次为奶粉、干酵母粉、小麦粉.结合不同配方饲料对美洲大蠊雌成虫其他生物学指标的影响结果,最终获得了美洲大蠊雌成虫的优化饲料配方组合方案:60 g奶粉、5 g干酵母粉和30 g小麦粉.     

Cloning and Sequencing of the Pokeweed Antiviral Protein Gene and Its Expression in E. coli

The total RNA was isolated from pokeweed (Phytolacca americana ) leaves using the method of guanidine isothiocyanite and used as a template to amplify the deleted mutant pokeweed antiviral protein (PAP) gene by RT-PCR and then the gene was cloned into the pGEMR-T vector. The sequencing results showed that the PAP gene consisted of 711nt, which was 99.6% identical to the PAP gene reported by Lin et al (1991). The IPTG-inducible expression vector containing the PAP gene was constructed and transferred into the E. coli strain BL21 (DE3)-plysS. A specific protein was produced after induction with 0.4m mol/L IPTG and its molecular weight was 26ku. The results of the double diffusion on the agar plate and the western blotting test showed that the protein produced in E. coli was highly identical with the PAP extracted by a Frenchman from French pokeweed leaves. These revealed that PAP gene was actually achieved and exactly expressed in E . coli.     

紫貂、松貂与美洲貂背中部冬季直针毛的结构差异

利用钢直尺、H6303i生物显微镜及配套的图片处理、测量软件系统(重光数码显微系统),测量紫貂(Martes zibellina)、松貂(Martes martes)和美洲貂(Martes americana)的背中部冬季直针毛长度、细度、近毛根细度、髓质细度、毛根无髓段长度及各类型鳞片比例等形态学指标;使用SPSS19.0对比分析测定数据。结果表明:紫貂、松貂和美洲貂的直针毛均呈典型纺锤型,髓质花纹类型均为网格型-B,鳞片类型、排列顺序、主要鳞片类型相近。松貂直针毛的长度、细度、髓质细度、毛根无髓段长度、扁平型鳞片比例显著高于紫貂(P0.05),而瓣状型鳞片比例明显低于紫貂,在其他性状方面二者差异不显著(P0.05);美洲貂的直针毛细度、扁平型鳞片比例显著低于松貂(P0.05),毛长度、髓质细度、近毛根细度、髓质指数等性状方面二者差异不显著(P0.05);紫貂和美洲貂只在直针毛的细度上表现出明显的差异(P0.05)。     

美洲大蠊和东亚飞蝗的耐缺氧力及其比较

研究并比较了美洲大蠊和东亚飞蝗在接近真空和充满CO2的环境下的耐缺氧力。结果表明：美洲大蠊和东亚飞蝗在0.06pa的真空泵中都能存活,在2～10min后其生理活动会不断减弱,直到假死或静止不动,但不会死亡,90～120min后两者的生理活动逐渐恢复,但都比正常状态下弱,生理活动都呈现反抛物线的规律,且在同一时间东亚飞蝗比美洲大蠊的生理活动要弱;美洲大蠊在充满CO2的密闭瓶中存活的时间比东亚飞蝗要长,将不同程度缺氧处理后的试虫置于空气中后,美洲大蠊恢复正常生理活动的能力和恢复后的活动强度明显比东亚飞蝗强。说明美洲大蠊和东亚飞蝗都有较强的耐缺氧力,但美洲大蠊的耐缺氧力更强。     

锰对商陆根际微生物及土壤酶的影响

进一步阐明植物对锰毒的耐性机制,通过盆栽试验对不同Mn浓度下美洲商陆根际微生物及土壤酶活性的影响及用顺序浸提法研究商陆根际Mn形态与6种土壤酶的关系.结果表明:1)随Mn浓度的增加,真菌数量逐渐减少,细菌、放线菌数量变化呈波动性.2)低浓度Mn可刺激脲酶、磷酸酶的活性;高浓度下,脲酶、蛋白酶、转化酶、过氧化氢酶、磷酸酶活性均受到不同程度的抑制;多酚氧化酶活性在高浓度下增加.3)相关分析表明,锰浓度与土壤酶活性间存在显著负相关性,相关程度为过氧化氢酶＞脲酶＞磷酸酶＞多酚氧化酶＞蛋白酶＞转化酶;脲酶、蛋白酶、转化酶、多酚氧化酶、磷酸酶5种酶的活性间呈显著正相关,表明它们对锰胁迫有相似的适应性.过氧化氢酶、脲酶对锰的影响作用最敏感.4)土壤酶与锰化学形态多呈线性关系,各形态Mn与脲酶、磷酸酶、过氧化氢酶活性均呈显著或极显著负相关,而与转化酶活性的负相关性很小,全Mn与蛋白酶活性及专性吸附态Mn与多酚氧化酶活性的相关性显著.5)各形态锰含量与土壤酶活性的相关关系优于总量锰,因此可将锰各形态含量关系作为评价红壤锰污染程度的主要生物学指标.     

美洲商陆抗病毒蛋白cDNA转化烟草的研究

构建两个美洲商陆抗病毒蛋白(Pokeweed antiviral protein,PAP)基因的植物表达载体pBIPAP和pBIPAPv，通过农杆菌介导的叶盘法转化烟草，经PCR检测证实获得了转基因植株，接种实验显示转基因烟草对TMV具有一定的抗性。     

Efficacy of modified diatomaceous earth on different cockroach species (Orthoptera, Blattellidae) and silverfish (Thysanura, Lepismatidae)

Defined populations of American (Periplaneta americana), German (Blattella germanica), and Oriental (Blatta orientalis) cockroaches, and silverfish (Lepisma saccharina) were observed after exposure to deposits (25 g/m²) of a new 1,1,1–trimethyl-N-trimethylsilane-modified, highly hydrophobic diatomaceous earth (DE) formulation by using a computer-aided device measuring motility, circadian rhythm, and mortality under defined environmental and climatic field-simulating and exposure-enforced conditions. In a humid climate (85% relative humidity) with water and food offered ad libitum, complete population eradication could be achieved on the sixth day against B. germanica, on the eighth day against P. americana, and on the ninth day against L. saccharina, respectively. No population eradication occurred within 10 days of exposure when testing B. orientalis, showing a mean survival rate of 29.4 ± 6.7 % of the populations. When comparing the species-specific mortality rates with the results obtained from corresponding reference control groups, significantly higher mortality rates could be observed in B. germanica (F = 66; df = 52; P < 0.00001), P. americana (F = 344; df =66; P < 0.00001), L. saccharina (F = 253; df = 24; P < 0.00001), and B. orientalis (F = 422; df = 11; P < 0.00001). Overall, the efficacy of the hydrophobised DE examined ranked as follows: B. germanica > P. americana (F = 51; df = 24; P < 0.00001) > L. saccharina (F = 43; df = 24; P < 0.00001) >> B. orientalis (F = 9; df = 15; P < 0.000001). DE exposure resulted in complete disruption of the circadian activity in B. germanica and P. americana, but not when tested against B. orientalis, where the species-specific circadian motility peak was still preserved at lower levels after 10 days of exposure. In contrast to the cockroach species examined, no specific circadian rhythm could be measured in the L. saccharina control and treatment groups. Results indicate that hydrophobised DE originating from freshwater diatoms modified with 1,1,1-trimethyl-N-trimethylsilane can be successfully used for the control of infestations with German and American cockroaches as well as silverfish, but not against Oriental cockroaches. It is concluded that species-specific morphological, physiological and behavioural characteristics of insects influencing DE efficacy as well as the toxicological risk of modified DE to humans deserve further investigation.     

美洲大蠊药理作用及临床应用研究进展

近几年来对美洲大蠊的药理作用和药物开发研究越来越多,研究显示它具有药用价值广、不良反应低及资源丰富的特点,在医药领域中有较好的应用前景。该研究就美洲大蠊的药理作用及其临床应用的研究状况进行了综述,以期为美洲大蠊药物的进一步研究开发提供参考,为其临床合理应用提供科学依据。