板栗扦插繁殖试验

从１９９２－－１９９５年扦插１６０００个插条，成活率由１９９２年的２６％提高到１９９５年的９６％。共繁殖共根苗２２３９株，移栽１０００余株，长势良好。试验认为（１）嫩枝扦插生根率高于硬枝，从实生苗母树采集的插穗经生根剂处理中生根。（２）扦插时间以５月下旬至７月中旬较适宜，６月中，一旬为最佳时间。（３）扦插基质以珍珠岩＋石砂最合适，（４）生根剂以ＰＧＣ，ＰＲＡ液态高深度速蘸法为最佳。     

癸氧喹酯干混悬剂防治人工感染鸡球虫病的效果试验

通过对14日龄岭南黄鸡人工感染柔嫩艾美耳球虫卵囊,测定国家四类新兽药癸氧喹酯干混悬剂的抗球虫作用。研究结果表明,新兽药癸氧喹酯干混悬剂按照推荐剂量0.25g/L(15mg/L)饮水给药对鸡球虫病表现出高效的抗球虫活性,具有良好的预防鸡球虫病效果,达到100%的保护率,抗球虫指数高达202.2。     

油松毛虫幼虫种群动态格局的研究

本文在以6种分布型指数测定油松毛虫(Dendrolimus tabulaeformis Tsai et Liu)幼虫种群静态空间格局的基础上,通过聚类分析,可将油松毛虫幼虫种群在上树过程中的水平格局和垂直格局聚为两类:即前期型和中后期型;其6种分布型指数可分为三类:即(1)m~*/m,C_A,I_δ;(2)入;(3)C,L。     

新媒体时代科普工作原则--基于CAS理论视角

简述了新媒体和复杂自适应系统（CAS）理论的相关概念,辨析了传统科普和新媒体时代科普的不同,指出了新媒体时代的科普系统是CAS ,提出了用CAS理论指导新媒体时代科普工作的几点原则。     

Study of wavelet denoising in apple's charge-coupled device near-infrared spectroscopy

Discrete wavelet transform was used to eliminate the noise in the charge-coupled device near-infrared (CCD-NIR) spectra of apple. The influence of three parameters (wavelet function, decomposition level, and threshold) on the predictive ability of the calibration model was investigated. The result showed that the db, sym, and bior wavelet families performed well, while the coif, dmey, and haar wavelets were not able to denoise effectively. The best decomposition level was 2. The threshold selection rules of the default, Birge-Massart, and Penalty had good denoising results, while SURE, Sqtwolog, Heuristic SURE, and Minimax set all detailed coefficients to zero due to their high threshold values. The best denoising result was obtained with the combination of the bior3.3 wavelet function, two levels of decomposition, default threshold selection rule, and the soft thresholding method. The optimal model of soluble solids content was constructed. The relative standard deviation of prediction decreased from 7.79 to 5.82% after wavelet denoising.     

Inhibition of low-density lipoprotein oxidation and oxidative burst in polymorphonuclear neutrophils by caffeic acid and hispidin derivatives isolated from sword brake fern (Pteris ensiformis Burm.)

Several antioxidant compounds have been previously identified from sword brake fern (Pteris ensiformis Burm.) by DPPH bleaching and Trolox equivalent antioxidant capacity (TEAC) analyses. Among the isolates, 7-O-caffeoylhydroxymaltol 3-O-beta-D-glucopyranoside and hispidin 4-O-beta- D-glucopyranoside [6-(3,4-dihydroxystyryl)-4-O-beta-D-glucopyranoside-2-pyrone] were two new compounds. The aim of this study is to elucidate the possible effect of the aqueous extract of sword brake fern (SBF) and these two compounds in preventing atherosclerosis. The results demonstrated that SBF and these two compounds strongly inhibited Cu2+-mediated low-density lipoprotein (LDL) oxidation measured by thiobarbituric acid-reactive substances assay (TBARS), conjugated diene production, and relative electrophoretic mobility. The commercial antioxidant dl-alpha-tocopherol showed lower antioxidant activity than these two compounds at the same molecular concentration. SBF and these two compounds also suppressed N-formylmethionyl-leucylphenylalanine (fMLP)-stimulated reactive oxygen species (ROS) production in human polymorphonuclear neutrophils (PMN). These findings indicate that sword brake fern may prevent atherosclerosis via inhibition of both LDL oxidation and ROS production.     

2008―2021年新疆审定长绒棉品种主要性状演变分析

为全面了解近年新疆育成长绒棉品种的特征特性,对2008―2021年新疆维吾尔自治区主要农作物品种审定委员会审定的43个早中熟长绒棉品种和4个当前待审品种的主要性状演变情况进行分析.结果表明:2012年以来审定品种的铃重较之前明显增加,普遍在3.40 g以上;衣分总体表现较为平稳,皮棉产量受气候环境等因素影响波动较大;纤...     

The siderophore-interacting protein is involved in iron acquisition and virulence of Riemerella anatipestifer strain CH3

Riemerella anatipestifer causes epizootic infectious disease in poultry and serious economic losses especially to the duck industry. However, little is known regarding the molecular basis of its pathogenesis. The ability to acquire iron under low-iron conditions is related to the virulence of a variety of bacterial pathogens. In this study, a sip (Riean_1281) deletion mutant CH3Δsip was constructed and characterized for iron-limited growth, biofilm formation, and pathogenicity to ducklings. Results showed that siderophore-interacting protein (SIP) was involved in iron utilization and the sip deletion significantly reduced biofilm formation and adherence to and invasion of Vero cells. In addition, the sip gene was absent in 1 of 24 (4.17%) virulent strains and 2 of 3 (66.7%) avirulent strains of R. anatipestifer, and the sip gene from six R. anatipestifer strains, which belong to serotypes 1, 2, and 10, respectively, shared 100% amino acid identities to those of R. anatipestifer strains DSM15868 and RA-GD. These results suggested that siderophore-mediated iron acquisition may be an important iron-uptake pathway in R. anatipestifer. Animal experiments indicated that the median lethal dose of the CH3Δsip mutant in ducklings was about 35-fold higher than that of the wild-type CH3 strain. Thus, our results demonstrated that R. anatipestifer SIP was involved in iron acquisition and necessary for its optimal virulence.     

种植密度对河北夏玉米生理成熟后茎秆抗倒能力及产量的影响

河北地区由于受光热资源限制,夏玉米收获时籽粒含水率普遍偏高,成为阻碍机械粒收技术推广应用的重要因素。虽然通过延迟收获可降低籽粒水分,但茎秆倒伏问题将进一步增加粒收难度。基于此,本试验于2019年选择迪卡517(DK517)、京农科728(JNK728)和豫单9953(YD9953)3个适宜机械粒收的品种为材料,以郑单958(ZD958)为对照,2020年新增张单258(ZD258)、张粒178(ZL178)和郑原玉432(ZYY432)3个品种,并设置3个种植密度,分别为6×10⁴(D1)、7.5×10⁴(D2)和9×10⁴株·hm^-2(D3),研究品种间及种植密度对生理成熟期倒伏率、茎秆形态特征、解剖特征、力学特征及产量的影响。结果表明,试验所选品种除了对照ZD958,其他品种均于吐丝后67 d籽粒含水率降至25%以下,达到了GB/T 21962-2008 标准中机械粒收对籽粒含水率的要求,其中YD9953和ZL178在吐丝后67 d的籽粒含水率比吐丝后25 d平均降低了35.1和42.0个百分点。在生理成熟期,相同密度下YD9953、ZL178、ZYY432的总倒伏率显著低于其他品种,其中在D1和D2密度下的总倒伏率均低于5%,符合机械粒收对倒伏率的要求。分析倒伏相关性状发现,株高和穗位高对密度的响应因品种而异;各品种茎秆基部第3节间单位体积干重和抗折力均随密度的增加而降低。D3密度下,ZL178的节间单位体积干重与D1相比,降幅最小(7.9%)。D2密度下,YD9953、ZL178和ZYY432的抗折力比均值分别提高28.7%、21.5%和28.4%;相同密度下ZL178、JNK728、YD9953的维管束数目和木质化程度高于其他品种。相关性分析发现,倒伏率和纤维素含量与抗折力呈显著正相关(R²=0.70、0.51),可作为评定玉米茎秆抗倒伏能力的关键指标。D2密度下ZL178和YD9953的产量与对照ZD958差异不显著但高于其他处理。综合考虑品种脱水特性、产量和站秆期间抗倒伏能力,ZL178和YD9953在密度7.5×10⁴株·hm^-2下能够兼顾高产和抗倒。本研究结果可为河北夏玉米光热资源限制区推广机械粒收提供理论参考。     

控释肥配施玉米秸秆对麦季土壤酶活性及养分的影响

为了探究控释尿素掺混肥与玉米秸秆长期互作对麦季土壤酶活性和土壤养分状况的影响,基于华北平原棕壤区小麦—玉米轮作8年定位施肥试验,对比研究了玉米秸秆还田(S)与不还田条件下施用控释尿素掺混肥(CRF)与普通尿素掺混肥(BBF)对麦季土壤酶活性及土壤养分的影响。结果表明:秸秆不还田条件下,CRF处理较BBF处理显著提高土壤中性磷酸酶(返青期和成熟期)、蔗糖酶(返青期和孕穗期)和纤维素酶(返青期和孕穗期)活性及成熟期有机质、硝态氮和有效磷含量,其中,成熟期中性磷酸酶活性显著提高29.6%,硝态氮含量显著提高34.8%。秸秆还田条件下,BBF+S处理成熟期脲酶、纤维素酶,孕穗期中性磷酸酶活性显著高于CRF+S处理,其他时期2种类型掺混肥土壤酶活性无显著差异。CRF+S处理成熟期土壤全氮、有机质、硝态氮和有效磷含量显著高于BBF+S处理。氮肥种类和玉米秸秆还田的交互作用对土壤中性磷酸酶、蔗糖酶和纤维素酶活性及土壤全氮、硝态氮、铵态氮、有效磷和速效钾含量影响显著,秸秆还田较不还田处理显著提高中性磷酸酶、蔗糖酶活性、速效钾和有效磷含量。综上表明,玉米秸秆还田和不还田条件下控释尿素掺混肥较普通尿素掺混肥处理均能显著增加土壤有机质含量,提高小麦后期速效氮磷养分的供应强度和供应容量,其中玉米秸秆还田配施控释尿素掺混肥处理在提高土壤酶活性和土壤养分方面表现最优。研究结果可为秸秆还田下氮肥优化施用提供理论依据。