地膜覆盖对大蒜生长发育及产量的影响

地膜覆盖栽培大蒜试验研究结果表明，地膜覆盖栽培能够增高土温、提高土壤相对湿度．明显促进大蒜生长，加速发育，显著提高产量，平均０．１５公顷（１亩）产量可比对照提高５８．３３％，经济效益十分显著。     

窝铺山区森林植被水土保持效益及资源植物开发利用途径的研究

森林植被在涵养水源保持水土,减少土壤流失的作用很大,植物措施投资少,见效快、可长期发挥效益.对窝铺流域三年的治理及观测研究表明:森林植被保持水土效益明显;土壤侵蚀量小于其它植被类型;改善了生态环境;利于建立新的生态平衡,保证农业高产、优质稳定地发展.作者同时对研究区内的资源植物进行了调查分类,对资源植物的保护和开发利用提出了几个值得注意的问题.     

东北黑土带土地利用变化特征及生态敏感性评价

东北黑土带是我国重要的商品粮生产基地,土壤质量退化、水土流失等问题直接影响生态与粮食供给安全,为明晰东北黑土带土地利用变化特征及评价生态敏感性,以2000年、2005年、2010年、2015年、2020年东北黑土带5期土地利用数据为基础,采用转移矩阵、地理探测器、综合生态风险评价等方法,研究景观格局及生态风险变化趋势。结果表明：(1)2000—2020年,研究区未利用地面积增加1 035.7km²,水域面积减少975.8 km²,土地利用变化最明显,耕地是阶段性变化较为剧烈的土地利用方式;(2)不同自然因子对研究区土地利用方式的解释力存在显著差异,气温是土地利用方式变化的主导因素,风速与高程、气温、蒸发量、地温、气压、相对湿度、日照时间的交互作用对土地利用方式变化具有显著的协同增强作用;(3)随时间推移,研究区生态敏感性整体改善,高度敏感区域减少,轻度敏感区域增加,并且出现生态敏感高值区向北移动、低值区向南移动趋势,研究区生态敏感性高值区的形成可能与以风蚀为主的侵蚀作用有关。宏观尺度景观格局变化分析与生态风险评价对区域生态环境保护政策制定及实...     

近红外光谱技术在家禽养殖领域应用现状

近红外光谱是一种快速光谱分析的新方法,伴随着光谱技术与化学计量法的发展,近红外光谱已广泛应用于农业、食品、医药、石油化工等行业,极大地提高了各行业信息化水平。基于近红外光谱在家禽养殖领域的应用现状,本文总结了近红外光谱技术的发展及其在饲料成分检测和禽肉检测中的应用。在饲料检测和家禽肉类检测方面,通过将禽肉样品的光谱信息与质量指标的参考值相关联,建立了预测饲料和待测肉类高精度、高稳定性的数学模型。与传统方法相比,近红外光谱技术具有信息量大、数据计算速度快等优点。本文还归纳了近红外光谱技术在饲料品质检测和肉类品质检测的应用现状,指出了近红外光谱在家禽养殖领域的大规模应用推广的可能性。同时指出近红外光谱技术存在的问题和未来发展方向,结果表明近红外光谱技术在饲料和畜产品检测领域具有良好的发展前景和应用价值。     

Application of bubble separation for quantitative analysis of choline in Dioscorea (yam) tubers

A modified assay based on the AACC official method 86-45 (AACC, 2000) for the determination of choline in three cereals and three varieties of Dioscorea (yam) tubers was developed. When tested in wheat, rice, and oat flour, choline estimated by the modified method was 34.0-45.3% higher than that of the original AACC method. In a system with higher contents of starch and mucilage, such as Dioscorea (yam) tubers, extra procedures in sample preparation needed to be carried out to separate starch and mucilage. The choline contents of the following Dioscorea (yam) tubers using the original AACC method and the present modified AACC method through coupling an additional bubble separation procedure, respectively, were (mean +/- SD, mg/g solid) Keelung yam (D. pseudojaponicaY.) 0.92 +/- 0.09 and 2.21 +/- 0.12, Yangmingshan yam (D. alata L.) 0.77 +/- 0.09 and 1.78 +/- 0.28, and Ming-Chien yam (D. purpurea) 0.44 +/- 0.09 and 1.35 +/- 0.19. Choline was 231-306% higher than when the original AACC method was used. Dioscorea (yam) tubers were much higher in choline content than they were in cereals. Bubble separation is an appropriate procedure in the practice for the maximum assay of choline in yams. It is accurate, rapid, easy to handle, and especially good for recovering choline from a starch and polysaccharide-protein-containing system.     

Chemical synthesis, in vitro acetohydroxyacid synthase (AHAS) inhibition, herbicidal activity, and computational studies of isatin derivatives

Acetohydroxyacid synthase (AHAS) catalyzes the first common step in the biosynthesis of the branched-chain amino acids. As a result of its metabolic importance in plants, it is a target for many commercial herbicides. Virtual screening analysis inspired the evaluation of 19 commercially available isatin analogues and 13 newly synthesized isatin derivatives as novel AHAS inhibitors and for their herbicidal activity. The best compound demonstrated 95% inhibition of the activity of Arabidopsis thaliana AHAS at a concentration of 100 mg L(-1), whereas the herbicidal activities of three compounds reached 50% inhibition at a concentration of 10 mg L(-1) using the rape root growth test. CoMFA contour models were established to understand the structure-activity relationships for this class of AHAS inhibitor. The compounds were docked to the active site cavity of A. thaliana AHAS using FlexX, and the dominant binding mode was consistent with frontier molecular orbital from DFT calculations. This is the first comprehensive study of isatin derivatives as AHAS inhibitors and provides a valuable starting point for the design of new herbicides.     

云南烟草赤星病菌及近似种rDNA ITS序列分析

 为了进一步研究云南省烟草赤星病病原的系统发育关系,提取28份供试菌株的菌丝基因组DNA,进行rDNA ITS序列及两侧ITS序列扩增。28个供试菌株与GenBank中登录的链格孢属7个种（包括5个小孢子种Alternaria citri,A．alternata,A．longipes,A．mali,A．gaisen和2个大孢子种A．porri,A．solani）14个菌株的序列进行聚类分析：42个菌株明显地分成两支,供试菌株与5个小孢子种聚为一个分支,序列同源性高达99％～100％,没有明显的地域性差异;但另2个大孢子种聚为单独的一支,明显地与供试菌株和其他5个小孢子种区分开。rDNA ITSl 58S ITS2序列在相对保守的基础上又存在一定变异,在一些菌物属的研究中可作为分类鉴定、分子标记、系统发育的重要依据,但通过对世界各地Alternaria菌株序列的分析发现,rDNA ITS1 58S ITS2仅能将大孢子种和小孢子种分开,还不能作为区分不同地域不同来源菌株的标准。     

Suppression subtractive hybridization and microarray analysis reveal differentially expressed genes in the <Emphasis Type="Italic">Lr39/41</Emphasis>-mediated wheat resistance to <Emphasis Type="Italic">Puccinia triticina</Emphasis>

Wheat leaf rust caused by Puccinia triticina (Pt) is one of the most severe fungal diseases threatening the global wheat production. The use of leaf rust resistance (Lr) genes in wheat breeding programs is the major solution to solve this issue. Wheat isogenic line carrying the Lr39/41 gene has shown a moderate to high resistance to most of the Pt pathotypes detected in China. In the present study, a typical hypersensitive response (HR) was observed using microscopy in leaves of the Lr39/41 isogenic line inoculated with the avirulent Pt pathotype THTT from 48 h-post inoculation. Two Lr39/41 resistance-associated suppression subtractive hybridization (SSH) libraries with a total of 6000 clones were established. Microarray hybridizations were performed on all obtained SSH clones using RNAs extracted from leaves of the Pt-inoculated and non-inoculated Lr39/41 isogenic lines, and leaves of the Pt-inoculated and non-inoculated Thatcher susceptible lines. Differentially expressed clones were analyzed by significance analysis of microarrays (SAM), followed by further sequencing. A total of 36 Lr39/41-resistance-related differentially expressed genes (DEGs) were identified, many of which had been previously reported to be involved in the plant defense response. The expression levels of eight selected DEGs during different stages of the Lr39/41-mediated resistance were further quantified by a qRT-PCR assay. Several pathogenesis-related (PR) and HR-related genes seem to be crucial for the Lr39/41-mediated resistance. In general, a brief profile of DEGs associated with the Lr39/41-mediated wheat resistance to Pt was drafted.     

鸡贫血病雏鸡ND免疫后局部免疫组织抗体生成细胞变化

对感染鸡贫血病毒（ＣＡＶ）雏鸡新城疫（ＮＤ）疫苗免疫及其强毒攻击后局部免疫组织——盲肠扁桃体和哈德尔腺的ＩｇＡ、ＩｇＧ和ＩｇＭ抗体生成细胞数量的动态变化进行了检测。结果发现,ＣＡＶ感染雏鸡ＮＤ免疫后７、１４、２８ｄ及新城疫强毒（ｖＮＤＶ）攻击后,上述免疫组织的三种抗体生成细胞数量均不同程度地低于未感染ＣＡＶ的ＮＤ免疫对照雏鸡。其中盲肠扁桃体弥散区的ＩｇＡ减少最为明显。表明ＣＡＶ感染雏鸡消化道和呼吸道局部免疫组织对新城疫疫苗的体液免疫应答功能降低。新城疫强毒攻击后ＣＡＶ感染ＮＤ免疫雏鸡的免疫保护率也明显低于未感染ＣＡＶ的免疫对照雏鸡。     

稻田养殖水生绿肥对水层中氮素循环的影响

在我国南方水稻生产中,如何开辟新肥源以改良土壤、增产粮食是个重要课题.增辟肥源途径很多,其中探讨水稻田的养分循环,研究以田养田的技术措施是有价值的.本文拟在讨论水稻田水层的氮素循环基本特性的基础上,对水浮莲(Pistia stratiotes L.)在稻田放养和利用的技术及其效果作一介绍.