A novel photodegradable insecticide: Preparation, characterization and properties evaluation of nano-Imidacloprid

Imidacloprid (IMI) microcrystals were directly encapsulated with nature polysaccharides chitosan (CHI) and sodium alginate (ALG) through layer-by-layer (LbL) self-assembly. The coated colloids were characterized using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The in vitro controlled release pattern of IMI through the PE diffusion barrier was studied using a diffusion cell assembly at physiological pH of 7.4. Photocatalysts were characterized by Brunauer-Emmett-Teller (BET) surface area and SEM. The adsorption and photocatalytic activities of photocatalysts were evaluated by isothermal adsorption and IMI degradation under UV light and natural light illumination. The toxicity of the photodegradable insecticide was evaluated against the adult stage of Martianus dermestoides. The results showed that thermodynamically stable IMI microcrystals were obtained by association and had a mean length of 7 μm and a ζ-potential of −37.5. The drug loading and encapsulation efficiency were 56.15 ± 0.96% and 81.57 ± 0.96%, respectively. The polysaccharide capsules prolonged the release time of the encapsulated IMI crystals. Among the photocatalysts, SDS/Ag/TiO₂ had the highest photocatalytic activity. Toxicity of the novel 50% nano-SDS/Ag/TiO₂-IMI was higher in the adult stage compared to the 95% IMI as indicated by the lower LC₅₀ value.     

Phylogenetic characterization of a microsporidium (Nosema sp.) isolated from the mulberry pest, Hemerophila atrilineata

Microsporidia are a group of obligate intracellular unicellular eukaryotes that can parasitize a wide variety of other eukaryotes ranging from protists to invertebrates and vertebrates. In this study, we examined the microsporidium Nosema sp. isolated from the mulberry pest, Hemerophila atrilineata Butler, 1881, named herein "Nosema sp. HA". The fresh spores were long oval in shape, 3.8 +/- 0.4 microm in length and 1.9 +/- 0.3 microm in width. Analysis of tissue infection of silkworm, Bombyx mori Linnaeus, 1758, indicated that the midgut, Malpighian tubules, muscle, fat body, silk glands, hemocytes, nerve tissue and gonads of silkworm were infected with Nosema sp. HA. The complete rRNA gene sequence of this microsporidium contained 4 305 base pairs (GenBank Accession JN882299), including the large subunit rRNA (2492 bp), the internal transcribed spacer (187 bp), the small subunit rRNA (1232 bp), the intergenic spacer (279 bp) and the 5S region (115 bp). The organization of the rRNA gene is 5'-LSU-ITS-SSU-IGS-5S-3'. Phylogenetic analysis, comparison of sequence identities and the arrangement in the rRNA gene subunits suggested that this isolate is separate from other Nosema species.     

柴达木盆地节水型农业体系的建设与对策

本文在调查柴达木盆地农业用水现状与存在问题的基础上,总结农业节水经验,对作物的需水量进行了计算,依据当地经济、科技发展状况和水资源的可供量,研究了农业的节水途径和潜力,提出了建立节水型农业体系的对策。     

甜菜夜蛾人工饲料研究

在室温26±1℃,相对湿度75％～80％的条件下,分别以3种人工饲料和天然饲料(空心菜叶)对甜菜夜蛾幼虫不同龄期进行饲养比较。结果表明,除1龄幼虫成活率偏低外,3种人工饲料对甜菜夜蛾的发育历期和发育状况与天然饲料基本相似。以黄豆粉为主成分配制的人工饲料饲喂甜菜夜蛾,其化蛹率、蛹重、产卵量和雌雄性比等均优于天然饲料,而且具有配制简便、成本低、不易霉变的特点。通过3代的继代繁殖表明,无论是人工饲料,还是天然饲料,其继代的幼虫成活率和产卵量等均明显下降。     

湖南省农业信息化发展与农村经济增长关系的实证研究

为了研究湖南省农业信息化对湖南农村经济的促进作用,通过采用2000—2010年湖南省农业信息化指标与农业经济产出的相关数据,对农业信息化各项指标进行主成分分析后提取了信息化规模和信息化人力资源两个主因子并将其与农业经济产出进行了协整检验和格兰杰因果检验。结果表明：湖南省农业信息化水平与农村经济产出之间存在长期稳定的均衡关系以及双向的因果关系,最后根据结论提出了相关建议。     

不同叶龄鸭跖草对咪唑乙烟酸的耐药性

鸭跖草是黑龙江省大豆田危害严重的恶性杂草,而且其叶龄愈大愈难防除。作者通过盆栽试验及细胞显微技术研究不同叶龄鸭跖草对咪唑乙烟酸的耐药性差异及其与叶片显微结构的关系。结果显示,鸭跖草随着叶龄增大,对咪唑乙烟酸的耐药性增强,并在3叶龄时出现拐点;随着叶龄的增大,叶片表皮气孔密度显著下降;叶片厚度、叶片上下表皮厚度、栅栏组织及海绵组织厚度显著增大;10个栅栏组织细胞长度显著减小,栅栏组织排列由稀疏不规则向紧密规则的方向发展。以上变化是鸭跖草对咪唑乙烟酸耐药性增强的原因之一。     

诱导免疫哈密瓜的某些生理生化特性研究

 应用病毒、细菌、真菌,以及病原菌体及其代谢物作为诱导因子,已在多种作物上获得对病毒的整体免疫,有些已开始在田间应用,我们也曾应用人工诱导免疫的方法使哈密瓜获得对瓜类疫霉病的抗性。目前对植物诱导免疫的机理,尤其是用病原菌代谢物作为诱导因子进行了研究。     

徐州侧柏林林分密度与林木生长关系的研究

以徐州市侧柏人工林为研究对象,研究50年生侧柏人工林不同经营密度与林分生长之间的关系规律。根据调查数据,绘制了不同密度侧柏林的径阶分布曲线;建立了胸径、单株材积、林分蓄积与密度的相关数学模型;并选出适合徐州石灰岩山地侧柏林生长的最优模型,为徐州市侧柏人工林的密度管理和林分生产力的预测提供科学依据。       

丝瓜新型棚架高效省本栽培

介绍了丝瓜早熟高产栽培技术和新型棚架栽培形式，比较了几种支架形式的优劣，阐述了新型棚架投资省、成本低、田间管理方便等突出特点，便于在生产中快速推广应用。     

论竹的崇拜

文章通过民族学、民俗学和历史学资料论述了中华民族的竹崇拜文化现象，主要表现在五个方面：1．大量有关竹生人的神话传说，说明人类与竹有血缘关系；2．存在着用竹作为氏族或部族的族称或标记；3．存在着对竹的禁忌；4．存在着大量关于竹的祭祖活动，主要有入社、繁殖、祭祖三种仪式；5．有很多竹的模仿活动，如装饰、跳舞、音乐等。