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991.
992.
Luying Sun Fengbin Song Shengqun Liu Qingjun Cao Fulai Liu 《Archives of Agronomy and Soil Science》2013,59(14):1932-1943
ABSTRACTSustainable agricultural management practices have attracted increasing attention due to their significant roles in benefiting the functions and sustainability of agro-ecosystems. An integrated agricultural practice (IP) in a maize cropping system was developed by changing row spacing, adopting no-tillage and residue return in the Northeast China. A 12-year field study was carried out to evaluate the effect of IP and conventional practice (CP) on soil physical properties, microbial biomass and enzyme activity during the cropping season. The results showed that soil organic matter under IP was increased by 17.4, 9.88 and 6.69% in June, August and October, respectively, than CP. IP enhanced microbial biomass C (by 31.7, 25.1 and 30.4% in June, August and October) and activities of invertase, urease and phosphatase (by 27.2–38.0, 78.9–182 and 9.8–29.0%) compared to CP, possibly attributing to an increase in the soil microbial community. Furthermore, the soil pH, water content, nitrogen and phosphorus contents, microbial biomass and some specific enzyme activities varied with sampling time. It is concluded that IP improved soil quality and health by increasing organic matter content and microbial biomass and activity in maize field in Northeast China, suggesting that IP is a feasible management technology for sustainable agriculture. 相似文献
993.
Arginine (ARG) exerts many beneficial effects on animal body and enhanced angiogenesis, lactogenesis, which finally leads to the improvement in nitrogen (N) metabolism, reproduction, lactation, immunity and growth. Unfortunately, unprotected ARG will be degraded in the rumen and its price is high, thus feeding rumen-protected ARG seems to be uneconomical. Alternatively, N-carbamoyl glutamate (NCG) is structural analogue of N-acetyl glutamate, cofactor of cabamoyl phosphate synthetasel, is lower in rumen degradation compared to ARG. Additionally, rumen epithelial and duodenal cells have potentially utilized the NCG for ureagenesis. Supplementation of NCG to high yielding dairy cows increased plasma concentration of ARG and nitric oxide, decreased the plasma ammonia N and improved lactation performance and N utilization. Supplementation of NCG enhanced pregnancy rates in rats, improved litter size and fetal survival rate, thereby improved the reproductive performance of sows. Oral NCG supplementation increases plasma ARG and somatotropin levels, and increased growth rate and muscle protein synthesis in nursing piglets. The NCG is potential a relatively cheaper source of feed additive to offer vital compensation over oral administration of ARG, resulting in improved ruminant animal health and production. In this article, we reviewed the mechanism of AfiG biosynthesis by NCG and their significance in growth, reproduction, milk production and N utilization in ruminant animals. 相似文献
994.
995.
显微注射Ca^2+激活小鼠M Ⅱ期卵母细胞 总被引:2,自引:0,他引:2
胞质内显微注入Ca^2+可以激活小鼠M Ⅱ期卵母细胞,且随着卵龄的增加,激活率明显升高。卵龄小于16h(hCG注射后)注射Ca^2+引起的激活率很低,卵龄超过18h,激活率达到50%以上。卵龄小于16h的卵母细胞,卵内注入超纯水未能激活卵母细胞,而在18 ̄19h卵龄组,注射水的对照组激活率为35%,但显著或极显著地低于注射Ca^2+的试验组。激活前注射EDTA卵母细胞的激活率约为30%,激活后注射 相似文献
996.
Jichong Zhang Agnes Murphy Gongshe Liu Benoit Bizimungu Qiang Liu Yves Leclerc Ti Xing Xiu-Qing Li 《Scientia Horticulturae》2011
Heritage potato varieties in Canada are historic old varieties collected from Canada and various countries before the formal establishment of the Canadian plant variety registration system and may be a valuable gene resource for beneficial traits in potato breeding and bioproducts development. Greater evaluation is the key for the enhanced use of these materials. It is unknown how much variation of starch granules occurs among Canadian heritage potato varieties. We analyzed the starch granule size of 14 potato heritage varieties held in the Canadian Plant Gene Resources collection over 2 years using a squeezed juice and microscopic method recently developed at the Potato Research Centre. The varieties demonstrated considerable variation in starch granule size and shape. The granules showed average lengths ranging from 18 μm in the variety Congo to 32 μm in ‘Russet Burbank’. The largest single granule measured from 64 μm in ‘Congo’ to 91 μm in ‘Crotte d’Ours.’ The granule sizes of the varieties showed a very high correlation (r = 0.975, P < 0.0001) between years. This high reproducibility suggests the existence of genetic factors in determining starch granule size. We also found that the starch granule size is positively correlated with tuber dry matter (in terms of specific gravity) in these heritage potatoes. The results demonstrated reproducible genotypic variation for starch granule size and shape in tubers with a significant correlation to tuber dry matter in these heritage potato varieties, and offers the possibility for and agronomic relevance of genetic modification of starch granules through selective breeding. 相似文献
997.
1 设立公路动物防疫监督检查站的重要性与紧迫性 赣州市位于江西省南部,辖18县、市(区),境内有105、323、206、319国道纵贯或横穿,是江西及湖南、湖北、四川、重庆、河南、山东、安徽。东北乃至内蒙古等省、市、自治区装载活畜的车辆进闽入粤的必经之地。装载活畜的车辆自北向南或由西向东途径数千公里驰进赣南,如此长时间、远距离行驶,途中感染疫源的确在所难免。危险的是这些车辆有的消毒不严,或者不接受消毒;有的装载病、死畜或隐性症状的活畜(禽),沿途抖落粪便和污染物;有的车主甚至乱抛或贱卖病死牲畜,致… 相似文献
998.
荧光显微技术在枣疯病病原鉴定中的应用 总被引:9,自引:1,他引:8
以易感染枣疯病的阜平大枣为试材,对影响枣疯病病原荧光显微观察的主要因素进行了系统研究。结果表明:苯胺蓝(aniline blue)、DAPI(4’,6-diamidino-2-phenylindole·2HCI)和阿的平(quinacrine)3种荧光染料均可用于枣疯病病原鉴定,其中以DAPI效果最佳。DAPI用于定性分析的是了适浓度为0.3μg·mL^-1,用于定量分析的最适浓度为1.0μg·m 相似文献
999.
在距蜂箱10 m 的地点放置质量浓度为0.75 kg· L- 3的蔗糖液,以测定各日龄意蜂的个体采蜜量.结果表明,采集蜂最小日龄为3 日龄,13~27 日龄段的工蜂采蜜量最高,每只蜜蜂每次采集69.44~75.25 m g;12 日龄以前的标记蜂采蜜量不稳定,随着日龄的增长逐渐趋于稳定;在测定地点,标记蜂11 日龄开始明显增多,直到28 日龄后减少.根据实验结果可以初步判定,近距离采集的适龄采蜜蜂为 13~27 日龄.此项研究结果对蜜蜂饲养管理技术的改进有重要参考价值. 相似文献
1000.
长输管道水力瞬变仿真 总被引:2,自引:0,他引:2
根据各种管道边界的瞬变方程和管道水击的连锁Allievi方法,针对具有实际元器件和边界的长输管道的不稳定流动,设计了基于特征线差分解法的分析流程和仿真计算程序。利用长输管道水击数值计算所得线路上各节点的瞬态值进行B样条曲线拟合,实现了水力瞬变过程中线路水力坡降线及某些水力参数变化情况的图形输出 。 相似文献