禽类味觉系统研究进展

文章基于哺乳动物的味觉系统,分析了家禽味觉的结构和功能,着重从不同类型的味觉受体的研究进展进行了综述,并指出了今后禽类味觉的研究方向。     

对尼日利亚的甜橙穗砧组合抗裂皮类病毒的评价

在尼日利亚,柑桔裂皮类病毒病限制了维生素C重要来源——甜橙的生产。该病只能应用抗病植株的芽接得以防治,因此本文对甜橙穗砧组合在自然条件下抗裂皮类病毒作一评价。     

软粒冬小麦高蛋白育种

为解决蛋白质问题,提高小麦蛋白质含量的育种愈来愈受到人们的重视.目前,全世界已汇集了大量蛋白含量高的(超过一般2-3%)软粒冬小麦品种和类型,但在另一些生态条件和农业技术条件下种植时,这些类型并不是总能表现出固有的优点.因此,不同耕作条件下保持该性状的稳定性,对培育高蛋白新品种来说则是最重要的一项要求.作物的产量与蛋白含量间存在的负相关关系、高蛋白遗传源的缺乏,以及这一性状显著的表型变异,都对提高蛋白质含量的育种工作造成了一定困     

铜对番茄的毒害

<正> 在北佛罗里达州,含 Cu 杀菌剂广泛用于支架番茄(Lycopersicon esculentumMill.)病害防治。一种番茄常用的含Cu(OH)_2杀真菌剂,每年可使耕层土壤的Cu 含量增加15mg/kg。已经证明,施于土壤的 Cu 只有极少一部分可被水淋溶,因此连续种植番茄若干年后,Cu 在番茄田中积     

不同年代的埃特纳火山土壤上用甘油萃取有机质的特性

We characterized humic acids (HAs) and glycerol-extractable organic fractions (GEOFs) extracted from four Andisols, taken from comparable soil-climate conditions on the east side of Mount Etna. The soils were formed on old lava (about 9 000 years ago), old tephra (about 8 700 years ago), recent lava (about 2 600 years ago) and recent tephra (about 3 600 years ago). A part of the organic matter of the soils, deprived of HAs and fulvic acids (FAs), was isolated by glycerol extraction. The GEOF can not be extracted with alkaline solutions, probably because it is closely bound to the mineral component of the soil. The characterization of the extracted organic fraction was carried out using elementary and functional group analysis and Fourier transform infrared (FT-IR) spectroscopy. About 20 extractions were necessary to extract the HA and FA from the older soils and about 10 extractions to extract them from the younger soils. Data showed that the GEOFs had a greater ash content and a smaller N content, as well as a greater presence of aliphatic compounds and carboxylic groups as compared to the HA extracted from the same soil. The GEOFs extracted from younger soils also had a lower yield, ash and COOH-group content, and were more aliphatic than the GEOF extracted from older soils. Finally, the GEOFs were more closely bound to the amorphous component of the soil (‘short-range’ minerals) and consequently less subject to biodegradation.     

免疫小鼠的腹水在植物病毒学中的应用价值

近来,Matthews阐述了用小鼠制备抗血清的优缺点。主要优点是实验所用的自交系小鼠很易大量饲养。缺点是从每只鼠身上只能获得很少量(1毫升或更少)的血浆,而且不能象在兔子身上那样有效地产生抗体。这是用芜菁黄花叶病毒(Turnip yellowmosaic virus)分别免疫鼠、兔进行比较得出的结论。但是应该指出,一只鼠只要用10—100微克病毒免疫就能制备出滴度为1/256     

抗生素在动物饲养中的应用效果

在畜牧业中,许多国家为了提高生产率和改善饲料营养物质的吸收率,广泛应用抗生素已经有20多年了。美、英、法、加拿大、联邦德国、意大利、捷克、南斯拉夫、罗马尼亚、保加利亚、波兰等国家对抗生素的应用最活跃。抗生素作为饲料添加剂应用是允许的,但它不能属于医学和兽医学上应用的抗生素,也不能在动物体内有蓄积作用。已经证实,某些抗生素能按不同的方式影响牛、猪、     

森林生态系统中土壤有机质组分的固态13C核磁共振波谱表征

Forest management practices such as prescribed burning and thinning in forest ecosystems may alter the properties of soil organic matter (SOM).In this study,surface soils from field plots in the Bankhead National Forest,Alabama,USA,were used to investigate possible SOM transformations induced by thinning and burning.Elemental analysis and solid-state 13C cross polarization magic angle spinning nuclear magnetic resonance (13C CPMAS NMR) spectroscopy were used to characterize SOM fractions in whole soils,humic substances,and density fractions.Our data revealed that the changes in SOM fractions due to the repeated burning carried out in the forest ecosystem studied were involved mainly with alkyl C,O-alkyl C,and carbohydrate functional groups,implying that most prominent reactions that occurred involved dehydrogenation,de-oxygenation,and decarboxylation.In addition,burning and thinning might have also affected the distribution and composition of free and occluded particulate SOM fractions.The limited structural changes in SOM fractions suggested that low-intensity prescribed fire in the forest ecosystem studied will not create major structural changes in SOM fractions.     

在圆形流水槽中精养草鱼

1.材料和方法平均全长为6.1厘米、体重为2.7克的草鱼鱼种,按每升水0.53、1.06、1.59,2.11尾的不同放养密度放养于每个容积为380升的6个圆形纤维玻璃水槽。鱼在试验前先驯化两周,用锅炉和混合阀保持水温在24.7±1.2℃。为了充气,水以45°角喷流入每一水槽中,使水面形成反时针方向的水流,水流速为7.57升/分钟,50分钟水交换一次。试     

家禽营养研究及其未来策略

维持家禽的遗传潜能和保证家禽生产性能和健康管理的进化体系,推动了家禽营养学的发展.在过去的50年期间,人们制订了定量原料和日粮中可利用营养素测定的方法,使得在家禽生产中能够做到饲喂时的营养水平很精确,从而保证家禽的生产性能或繁殖性能.但在精确营养需要时,没有对能量进行规范.