播期推迟对冬小麦产量形成和籽粒品质的调控效应

为了明确推迟播期对小麦产量形成和品质的影响,选用2个冬小麦品种(轮选987和京冬8号),在大田条件下研究了播期推迟对小麦群体动态、物质积累、产量构成和籽粒品质的调控效应.结果表明,播期推迟能显著降低小麦冬前分蘖数,促进春季分蘖的发生和成穗,提高分蘖成穗率.播期对小麦植株干物质积累的影响存在基因型差异.播期推迟引起小麦产量构成因素的变化,进而导致籽粒产量下降,且京冬8号出现显著下降时对应的播期早于轮选987.播期推迟后小麦籽粒中的淀粉含量呈下降趋势,蛋白质含量呈上升趋势,同时二者的主要组成成份也随之改变.因此,冀东地区选用轮选987且适当早播(10月5日播种)可以获得高产;推迟播期至10月10日则籽粒品质提高,但要注意加强小麦生育后期的田间管理,防止粒重明显降低.     

理囊散治疗排卵延迟不孕奶牛血清微量元素与激素的相关性分析

[目的]探讨理囊散治疗排卵延迟不孕奶牛血液生殖激素和微量元素含量关系,分析其相关性与回归方程.[方法]采用ELISA法测定理囊散治疗排卵延迟不孕奶牛前后血清中促卵泡激素（FSH）、促黄体激素（LH）、孕激素（P）和雌二醇（E2）的浓度,采用原子吸收光谱法测定血清Cu、Fe、Mn和Zn含量,分析4种激素和4种微量元素间的相关关系与回归方程.[结果]P浓度与Cu、Mn、Zn含量呈正相关,而与Fe含量呈负相关.E2浓度与Cu、Fe、Zn含量呈正相关,而与Mn含量呈负相关.FSH浓度与Fe含量呈正相关,而与Cu、Mn、Zn含量呈负相关.LH浓度与Cu、Fe含量呈正相关,而与Mn、Zn含量呈负相关.[结论]排卵延迟不孕奶牛血清中微量元素含量对激素的分泌有影响.     

Delayed-type hypersensitivity skin test against Neospora caninum in heifers with undetectable specific antibodies

Delayed-type hypersensitivity (DTH) has been used in human and veterinary medicine as a skin testing for evaluating in vivo cell-mediated immune responses (CMIR). Whereas CMIR is a key process to control intracellular pathogens, its value at identifying cattle exposed to the abortigenic intracellular coccidian parasite Neospora caninum is unknown. In this work, we have evaluated a DTH skin testing in cattle exposed to N. caninum and still seronegative. Female calves were experimentally sensitized by subcutaneous (SC) inoculation with live tachyzoites of N. caninum (NC-Argentina LP1) in sterile phosphate-buffered saline (PBS) (group A; n: 8) whereas other calveswere mock-sensitized with PBS (group B; n: 6). Two DTH skin tests were performed by intradermal inoculation with a soluble lysate of N. caninum tachyzoites (NC-Argentina LP1) in the neck region at 60d and 960 d after sensitization. Skinfold thickness at the intradermal inoculation site was measured at 0, 24, 48 h post each DTH skin test and skin biopsies taken for microscopic evaluation. Specific N. caninum antibodies kinetics was evaluated all throughthe experiment. We found that whereas N. caninum specific antibodies remained below the ELISA cut-off, a distinctive skinfold thickness increase was detected in sensitized animals (group A) at the DTH skin test site, showing induration, swelling and inflammatory infiltration. Mock sensitized animals (group B) showed no skinfold thickness growth and lacked specific antibody response. Thus, N. caninum DTH skin testing could be a useful diagnostic tool for the detection of CMIR during N. caninum infection in non-humoral responders.     

Cervix–rectum temperature differential at the time of insemination is correlated with the potential for pregnancy in dairy cows

This study sought to establish whether temperature gradients between the cervix, vagina, and rectum at and 7 days post-artificial insemination (AI) were associated with the incidence of pregnancy in lactating dairy cows (Experiment I; n = 90 ovulating cows) and to evaluate temperature gradient dynamics from the time of insemination to 7 days post-AI under heat stress conditions (Experiment II; n = 16 ovulating and 4 non-ovulating cows). In Experiment I, 39 cows (43.3%) became pregnant. The odds ratio for pregnancy was 2.5 for each one-tenth of a degree drop in cervical temperature with reference to the control rectal temperature at the time of AI (P = 0.01), whereas the same decrease in the cervix–rectum temperature differential 7 days post-AI resulted in an odds ratio of 0.44 (P = 0.02). In Experiment II, 5 of the ovulating cows (31.3%) became pregnant. The mean values of the vagina–rectum, vagina–cervix, and cervix–rectum temperature differentials at AI (day 0), 8 h, 24 h, and 7 days post-AI changed significantly from day 0 to day 7 (within-subject effect; P < 0.02) in ovulating cows but not in non-ovulating cows. Temperature differentials on days 0 and 7 were similar between ovulating cows and cows of Experiment I. Overall, our findings support the notion that a temperature differential between the caudal cervical canal and rectum at AI may be an indicator of the likelihood of pregnancy. Possible prospects of confirming estrus at the herd-level are also suggested.     

氮素后移施肥对大豆产量及品质的影响

在保持磷钾肥不变的前提下,控制氮肥总量,将适量的氮肥用作基肥和种肥,其余氮肥后移分期施用研究氮肥对大豆产量及品质含量的影响。结果表明:大豆氮肥后移分期施用增产效果显著,不同处理间差异达到了极显著水平,以N6处理(纯N量种肥15 kg·hm-2、始花期追氮30 kg·hm-2、始花期喷氮7.5 kg·hm-2及鼓粒期喷氮7.5 kg·hm-2)产量最高,产量为3 285.71 kg·hm-2。大豆始花期追施氮肥的增产作用大于始花期、鼓粒期喷施氮肥,始花期和鼓粒期分期喷施氮肥增产效果好于始花期一次性喷施。氮肥后移分期施用对大豆的油分与蛋白质含量有较明显的影响。充足的底肥或种肥氮有利于提高大豆油分含量,而氮肥后移施用明显降低了油分含量,随着始花期追施氮肥量的增加,大豆油分含量呈递减趋势;对大豆的蛋白质含量影响作用与油分正好相反,氮肥后移分期施用使蛋白质含量显著提高,幅度为0.373 3%~1.323 3%;氮肥后移施用对大豆籽粒蛋脂总和的影响与蛋白质的变化趋势一致。     

A novel technique using 1-MCP microbubbles for delaying postharvest ripening of banana fruit

This study aimed to investigate the application of microbubble technology for delaying banana ripening. A preparation of 1-MCP designed for use as a form of aqueous micro bubble (MBs) solutions was formulated. Banana fruit were immersed in 500 nL L⁻¹ of aqueous 1-MCP microbubbles (1-MCP-MBs) or fumigated with 500 nL L⁻¹ 1-MCP, then stored at 25 °C for 8 days. 1-MCP-MBs were more effective in delaying postharvest ripening than conventional 1-MCP fumigation. 1-MCP-MBs reduced the respiration rate and ethylene production compared to the control and 1-MCP fumigated fruit. Moreover, 1-MCP-MBs delayed yellowing and maintained firmness of banana fruit during storage. These results indicate that 1-MCP-MBs can be used as an alternative method for delaying the postharvest ripening of banana fruit, and its application for other commodities needs to be further elucidated.     

红车轴草总黄酮对小鼠免疫功能的影响

［目的］研究红车轴草总黄酮对小鼠免疫功能的影响。［方法］设计迟发变态反应试验、炭粒廓清试验、脏器指数试验,每个试验均用40只小鼠,随机分成4组,设对照组与高、中、低剂量3个试验组。3个试验组分别给予85 mg/（kg·d）（高剂量组）,53 mg/（kg·d）（中剂量组）,22 mg/（kg·d）（低剂量组）红车轴草总黄酮灌胃,对照组以吐温-盐水液灌胃。［结果］3个试验组48 h足跖增厚与对照组均有增加,以中剂量试验组增加显著（P〈0.05）;中剂量组与低剂量组的吞噬指数较对照组有显著增高（P〈0.05）;脏器指数试验结果表明,试验组与对照组均有增加,但没有显著的统计学意义。［结论］试验全面评价了红车轴草总黄酮的各种生理药理功能及其对免疫功能的影响,为其开发应用提供了可靠的参考资料。     

延迟神经网络的分岔分析及其在混沌控制中的应用

研究了一个具有延迟反馈的神经网络模型的性质.利用多项式理论给出了其特征方程根的分布,得到了Hopf分岔产生的条件,并将结果应用到混沌神经网络的控制中.数值仿真结果验证了结论的正确性.     

新疆木纳格葡萄的丰产栽培

木纳格葡萄属欧亚种,具有品质优、耐贮运,晚熟等诸多优良特性,新疆自治区许多地、州广为栽培,是新疆主要的鲜食品种之一,具有良好的发展前景,本文就其丰产栽培技术做一简要的概述。     

关于在科研专项绩效考评中增加延迟性考评指标的思考

中央财政科研专项绩效考评制度的建立和实践有效地提高了科技经费效益,但是受科研项目规律影响,科研项目成果相对于科研经费投入存在一定的滞后期,目前的科研专项绩效考评无法对科研成果进行较完整的考核。文章回顾了我国中央财政对科研专项开展绩效考评的历史,分析了目前对科研专项绩效考评存在的不足,指出在现行考评制度框架基础上对科研专项引入延迟性考评指标,并对开展延迟性考评工作的适用对象、考评期限等提出有关建议。