The roles of cytokinins and abscisic acid in the pericarp of litchi (Litchi chinensis Sonn.) in determining fruit size

Summary

Variations in the concentrations of cytokinins (CTKs) and abscisic acid (ABA) were studied in the pericarp of litchi (Litchi chinensis Sonn.) fruit using the large-fruited cv. ‘Erdanli’ (55.3 g per fruit) and the small-fruited cv. ‘Huaizhi’ (20.9 g per fruit), as well as large fruit (32.4 g) from early blooms and small (20.8 g) fruit from late blooms on the same inflorescences of cv. ‘Feizixiao’ from the same commercial orchard in Guangdong, China in 2000. ‘Erdanli’ had higher concentrations of CTKs than cv. ‘Huaizhi’ on three out of six sampling dates during fruit development, and lower concentrations of abscisic acid (ABA) from 40 d after anthesis. In cv. ‘Feizixiao’, fruit from early blooms had higher concentration of CTKs than fruit from late blooms at all sampling dates, and lower concentrations of ABA on three out of five sampling dates. Therefore, the former had a higher CTK:ABA ratio. These data suggest that a high CTK:ABA ratio favours fruit growth in litchi.     

哺乳类和鸟类动物隐孢子虫交叉感染试验研究

为了明确哺乳类和鸟类宿主隐孢子虫能否交叉感染，分别从鸡、兔、小白鼠、鸭、鹌鹑分离到隐孢子虫进行交叉感染。结果，从鸡分离的隐孢子虫卵囊能感染鸭、鹌鹑、麻雀，而不能感染鸽、大白鼠、小白鼠、兔，从鸭分离的卵囊能感染鸡，从兔、小白鼠分离的卵囊不能感染鸡、鹌鹑，从鹌鹑分离的卵囊不能感染兔、大白鼠、小白鼠和鸡。提示隐孢子虫在宿主纲水平上有宿主特异性。     

大学生旷课心理分析及对策

采取抽样问卷及访谈形式对海南4所高校的大学生旷课心理进行调查,在此基础上进行大学生旷课心理活动分析,大学生旷课心理分析,提出大学生旷课行为的应对策略。     

杀虫植物非洲山毛豆的研究

非洲山毛豆原产于热带非洲,是一种优异的杀虫植物。本文对其生物活性、杀虫有效成分、作用机理、加工使用等方面进行了概述。     

Synthesis and insecticidal activities of novel oxime ether pyrethroids

A series of novel 2-methylthio-3'/4'-substituted acetophenone oxime O-ethers were synthesized by the reaction of the corresponding acetophenone oximes with halides of pyrethroid alcohols in the presence of sodium hydroxide and phase-transfer catalysis or with triethyl quaternary ammonium salts of halides of pyrethroid alcohols in the presence of sodium hydroxide. These compounds showed notable insecticidal activity against Homopteran and Lepidopteran pests. 2-Methylthio-4'-fluoroacetophenone oxime O-[(2-methylbiphenyl-3-yl)methyl] ether was more effective than the commercial insecticides chlorfenapyr and fenvalerate.     

几种药剂防治柑橘黑斑病的田间药效试验

为筛选出防治柑橘黑星病的有效药剂,以南丰蜜橘为研究对象,对柑橘黑斑病进行田间防治试验。结果表明:10%苯醚甲环唑1000倍防治效果最好,防治效果为92.32%;80%代森锰锌+70%甲基托布津复配500倍防治效果次之,防治效果为91.45%;依次是80%代森锰锌400倍、70%甲基托布津400倍和10%苯醚甲环唑1500倍,防治效果分别为87.32%、84.65%和83.56%。     

三菌混合固态发酵苹果渣产复合酶的研究

利用实验室保藏的多株菌种,对苹果渣进行三元混菌固态发酵产复合酶。以纤维素酶、木聚糖酶、果胶酶活性大小为测定指标,对筛选出单菌活性较高的菌株,按照1:1:1进行3种菌混合发酵,确定混菌后效果较好的3种菌。考虑到试验因素之间的交互作用,以3种菌的接种比例及接种时间间隔作为试验因素,通过正交表交互作用设计试验及分析,确定3种菌混合活性最佳时间间隔为菌种#1、#2、#3同时接种;接种#1体积1ml、接种#2体积2ml、接种#3体积1ml。混菌后酶活性比3种单菌的酶活分别提高了10.9%、2%、20%,达到了优化的目的。     

一种改进的尖孢镰刀菌的实时荧光定量PCR检测方法

为实现荧光定量PCR对土壤病原真菌数量更为高效、灵敏的检测,本研究将液体培养的孢子悬浮液和长年耕作的水稻土制作成孢子浓度为4×10~1~4×10~6 spore/g的带菌土,采用MoBio PowerSoil@DNA Isolation Kit提取模拟带菌土壤总DNA,引入常规PCR预扩增包含qPCR目标序列的1 446bp片段,以预PCR产物为模板进行qPCR,构建荧光定量PCR标准曲线。研究结果表明:以试剂盒提取的带菌土壤总DNA为模板绘制的qPCR标准曲线相关系数r为0.985,检测下限为4×10~3 spore/g土;引入预PCR后,qPCR标准曲线相关系数r为0.974,检测下限为4×10~2 spore/g土,较未引入时提高了10倍,结合不同土壤病原真菌的特异性引物,该检测方法可为土壤病原真菌的有效定量检测提供技术支撑。     

Immunoadjuvant activities of a recombinant chicken IL-12 in chickens vaccinated with Newcastle disease virus recombinant HN protein

Recombinant fowlpox virus (rFPV/HN) expressing Newcastle disease virus (NDV) HN gene and rFPV/HN/chIL-12 co-expressing chicken IL-12 (chIL-12) and HN (rHN/chIL-12) genes have been characterized. rHN/chIL-12 or rchIL-12, expressed by our previous construct rFPV/chIL-12, co-administered with rHN was assessed for adjuvant activities of chIL-12. Chickens were vaccinated with various amounts of rHN/chIL-12 mixed with mineral oil (MO), intramuscularly. Levels of hemagglutination-inhibition (HI) antibody production depended on the concentration of the injected rHN or rHN/chIL-12. The lower HI antibody titers were obtained in chicken groups rHN/chIL-12/7-rHN/chIL-12/9, receiving 60ng rHN/8ng chIL-12 with MO, 30ng rHN/4ng chIL-12 with MO or 15ng rHN/2ng chIL-12 with MO, respectively, compared to those in chicken groups rHN/7-rHN/9, receiving rHN with MO alone. However, chickens in group rHN/chIL-12/7 or rHN/chIL-12/8 and rHN with MO alone showed the same effective protection. Chicken group rHN/chIL-12/9 was even more protective than that in group rHN/9. When rchIL-12 was co-injected with 15ng rHN plus MO, chickens produced low levels of HI antibody titers; while higher levels of IFN-γ production and an effective protection rate (83%) were obtained. On the other hand, low levels of IFN-γ production and low protection response (50%) were obtained in chickens injected with rHN with MO alone. Taken together, when the concentration of rHN decreased to certain levels, rchIL-12 reduced HI antibody production. The increase in the induction of IFN-γ production might suggest the enhancement of the cell-mediated immunity which conferred the protection from the NDV challenge.     

赤眼蜂寄主选择性及其机理研究(Ⅱ) 赤眼蜂对寄主的选择行为及其机理分析

3种赤眼蜂在多种寄主卵单独或共存条件下,趋向产卵的行为反应趋势相似。各“蜂—卵”组合之间,在上卵蜂率,偏嗜指数等行为反应指标上均有明显差异。该趋势与寄生特性不尽吻合,不同蜂种对不同寄主卵有各自的偏嗜性选择。繁蜂所用中间寄主卵,对蜂种原有的寄主选择嗜好性具有驯化改造作用,赤眼蜂对寄主卵的有机溶剂抽提物有敏感的趋向行为发生,赤眼蜂对寄主的选择性行为可能与寄主卵的化学信息物质有关。