作物残茬与生物篱组合对减轻土壤风蚀的作用

为了探究中国北方农牧交错带冬春风蚀季节生物篱与作物残茬组合对间作裸露秋翻地的防护作用,采用风蚀圈和野外移动式风洞试验的方法对研究区土壤风蚀情况进行监测,利用PC-3型自动气象站进行风速测定。结果表明,油葵秆生物篱减小了间作裸地近地面风速,提高了地表粗糙度;从防风蚀效果看草谷子茬优于油葵秆生物篱;在距油葵秆生物篱或草谷子茬下风向裸地不同位置处,土壤风蚀量基本呈先增加后减小的单峰曲线变化趋势,在4 m左右土壤风蚀量最大,在篱和茬的双重保护下,距茬5 m处发生了风积现象;土壤风蚀量降低率基本呈“V”字型分布;土壤风蚀模数随风速增大而增加,在生物篱的保护下5～15 m/s风速时土壤风蚀降低率为5.03%～20.53%。因此,油葵秆生物篱具有防风蚀作用,而且与草谷子残茬组合对间作裸地会起到更好的固土防蚀作用。     

三种南方典型水稻土长期试验下有机碳积累机制研究Ⅲ.两种水稻土颗粒有机质结构特征的变化

采用固体交叉极化魔角自旋¹³C核磁共振(CPMAS¹³C-NMR)波谱技术对长期不同施肥处理下红壤性水稻土和太湖地区黄泥土本体土壤以及水稳性团聚体中颗粒有机质（POM）的化学结构特征进行了研究。结果表明,不同施肥处理下本体土壤和不同粒径水稳性团聚体中POM的结构组成相似,主要由烷氧C、烷基C和芳香C组成,其中以烷氧C含量最高。施肥改变了本体土壤POM中各类C原子的相对百分含量,有机肥以及化肥配施有机肥条件下烷氧C含量明显降低,芳香C和酚基C含量有不同程度的增加,表明POM的稳定性增强;单施化肥下烷氧C含量最高,而烷基C、芳香C和芳香度均最低,POM的稳定性减弱,不利于POM的积累。施肥改变了黄泥土不同粒径水稳性团聚体中POM各类C原子的相对百分含量,从而使得不同粒径中POM对其团聚体的稳定性作用发生变化;而红壤性水稻土不同粒径水稳性团聚体POM各类C原子的相对百分含量并未明显受到施肥措施的影响。     

锌在养猪业中的应用

本文概述了锌在猪体内的分布、存在形式、代谢需要量与生理作用,阐述不同锌源对猪的生产性能的影响及其应用现状,揭示了合理利用锌源、降低生产成本、减轻对环境污染的重要性。     

吉林省黑豆种质资源调查报告

通过对吉林省60份黑豆品种的主要性状调查分析结果表明,平均为0.13g／粒(0.0031—0．1400g),均属小粒型。粒型以椭圆(31．67％)和肾形(30.00％)为主,其次是扁椭圆形(15.00％)。生育习性以直立型为主占55．00％,半直立和半蔓生型分别为23．30％和16．67％。无限结荚习性占主导地位为93.33％。植株平均高度为110．64cm,几乎全部为高杆类型。但品种间差异较大(100．61—141．11cm)。子叶全部为黄色,椭圆形叶占96．67％。棕色茸毛占76．67％,紫花占68．33％。并且发现紫花与棕色茸毛多一起出现。脐色中比例最大的是黑色占46.67％。平均生育日数为127d。各地区间基本没有差别。蛋白质平均含量为43．04％,脂肪平均含量为17。44％。通过对比筛选出了抗旱、高蛋白质的优质种源ZDD07581号。     

脂肪细胞定向和分化因子1(ADD1)基因的研究进展

脂肪细胞定向和分化因子1(ADD1)是重要的核转录因子。ADD1不但是脂肪分化过程中重要的转录因子,同时还可以调控与脂肪代谢相关酶基因的表达。在人类和老鼠的研究发现ADD1基因与肝脏、脾脏等非脂肪组织的脂肪沉积有明确的连锁关系。实验研究提示:ADD1基因可能是影响动物肉质性状和屠体性状的候选基因。     

基层动物防疫工作新模式的探究

南郑县在2008年的动物防疫工作中,积极总结经验,创新了动物防疫工作模式,通过与能繁母猪养殖户签订一个合同,建立三个台帐,实行三包三挂钩,极大的调动了能繁母猪养殖户动物防疫和申报检疫的积极性,减轻了春秋两季普防压力,解决了免疫补针实施难的问题,提高了动物防疫密度和质量。通过认真开展仔猪产地检疫工作为重大动物疫病防控奠定了扎实的基础。     

鸭粪提取物对水稻纹枯病菌的影响及其有效成分分析

为探明稻鸭共养模式抑制水稻纹枯病发生的原因,以稻鸭共养模式的鸭粪提取物为研究对象,对其抑菌活性及有效成分进行了测定和分析,以期为水稻纹枯病生物防治提供新的途径。结果表明:鸭粪乙醇提取物对水稻纹枯病菌有抑制作用,24h内最高菌丝生长抑制率和EC50分别为88.64%、26.11mg·mL-1;鸭粪乙醇提取物经萃取分离得到石油醚和乙酸乙酯两种组分,其中石油醚组分抑菌效果较弱,乙酸乙酯组分抑菌能力较强,其对水稻纹枯病菌抑制率为89.70%,EC50为15.52mg·mL-1;对乙酸乙酯组分进行硅胶柱层析分离得到5种流份,其中第2流份有显著抑菌活性,在24h和48h内对水稻纹枯病菌的抑制率分别为89.58%和80.36%。GC-MS分析表明,鸭粪的抑菌物质主要为酚酸类和含硫醇有机物质,进一步纯化和鉴定有待研究。     

Cytotoxicity of cycloartane triterpenoids from aerial part of Cimicifuga foetida

Our previous study had demonstrated cytotoxicity of EtOAc fraction from aerial part of Cimicifuga foetida on various cancer cell lines. In the present study, we investigated the cytotoxicity of five cycloartane triterpenoids isolated from the EtOAc fraction. Compounds (1,2,3) showed moderate cytotoxic activity on R-HepG2 cells and drug resistant sub line R-HepG2 but exhibited less toxicity against primary cultured normal mouse hepatocytes. Compounds (4) and (5) were inactive on all tested cell lines.     

Catechin transformation as influenced by aluminum

Polyphenols (catechins) are vital biomolecules in tea plants (Camellia sinensis), which are well-known as typical Al accumulators. However, the interaction between Al and catechin remains obscured. The objective of the present study was to investigate the effect of Al on the transformation of (+)-catechin. Solutions with OH/Al molar ratios of 2.5 (pH 5.5) and 3.0 (pH 7.0) prepared at Al/catechin molar ratios (R) of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 were aged for 7 and 30 days, respectively. The precipitates were collected and examined by wet chemistry, X-ray diffraction, transmission electron microscopy, electron spin resonance (ESR), cross-polarization magic angle (CPMAS) 13C nuclear magnetic resonance (13C NMR) analyses, and Fourier transformation infrared absorption spectrometry (FT-IR). The weight of the precipitates increased with increasing Al/catechin molar ratios and with prolonged aging. The molar ratios of Al/catechin in the precipitates increased with increasing initial Al/catechin molar ratios and were close to the initial solution Al/catechin molar ratios. The chemical analysis and spectroscopic studies indicated that Al was bonded with catechin, forming a 1:1 type complex. The reaction of crystalline catechin with Al resulted in the formation of X-ray noncrystalline precipitates. The solid-state CPMAS 13C NMR spectra of the precipitates show the change in chemical shifts of catechin as a result of catechin complexation with Al. The FT-IR spectra of the Al-catechin precipitates also show the loss of absorption bands of several functional groups compared with catechin. The FT-IR data substantiate this reasoning. The ESR spectra of the precipitates show a single symmetrical line devoid of any fine splitting, indicating the presence of free radicals of semiquinones, which are commonly present in humified materials.     

FucP mediates fucose to regulate T3SS in Edwardsiella piscicida and promotes intestinal colonization in Tilapia

Aquaculture International - Edwardsiella piscicida (E. piscicida) is a common pathogen in freshwater and marine environments and an important intestinal pathogen of fish. Fucose large presence in...