多代驯化对布氏田鼠非繁殖期性激素本底水平的影响

为阐明驯化过程对季节性繁殖的布氏田鼠Lasiopodomys brandtii性腺活性的影响,采用放射免疫技术从秋季(11月)至翌年春季(3月)对室内驯化1月、3年和10年的雌雄鼠粪便中的性激素水平进行监测.结果 显示,在11-12月非繁殖季节,驯化10年组雄鼠睾酮水平分别达到3年组和1月组的3.5倍和13.3倍,驯化...     

略阳县五叶草莓种质资源调查与开发利用

为合理开发利用略阳县丰富的五叶草莓资源,本文对五叶草莓的种质资源分布状况进行了调查,发现略阳县五叶草莓主要有白果、粉果和红果3 种类型,平均单果质量0.86～1.27 g,果实可溶性固形物含量7％～9.5％,果实不耐贮藏,主要分布在海拔916～1 630 m 的地区,当地市场销售价格20～80 元/kg,此次调查可为五...     

蜜环菌和天麻、猪苓的关系及尚未大量人工驯化原因

主要概述了蜜环菌的主要特性和其与天麻、猪苓的关系,以及蜜环菌子实体尚未大量人工驯化的原因。     

Domestication of Silver Perch,Bidyanus bidyanus,Broodfish

Abstract

Most breeding programs for the Australian native freshwater silver perch, Bidyanus bidyanus, are based on fish originally captured from natural populations. However, over the last 20 years, there has been a dramatic decline in the distribution and abundance of silver perch in the wild and the species now has the conservation status of “vulnerable.” Unless broodfish can be domesticated a serious shortage is imminent. The aims of this study were to determine the age and size at sexual maturity and the reproductive performance of silver perch reared in captivity. Fingerlings (mean weight, 4.0 g) from a hatchery were stocked into an aerated 0.32-ha earthen pond at a density of 22,000 fish/ ha for 12 months, harvested, and restocked at 10,000 fish/ha for a further 2 years. The fish were fed a formulated diet containing 35% crude protein. No fish were mature at 1 year of age; at 2 years, most males (93%; total length, 304.0 mm, weight 412.7 g), but no females were mature; and at 3 years, most females (97%; 316.4 mm, 549.6 g) were mature. Three-year-old fish injected with 200 IU/kg human chorionic gonado-trophin spawned viable gametes. High fecundity (mean 139,286 eggs/ kg), fertilization rates (84.5%) and hatch rates (76.8%) demonstrate that broodfish can be domesticated and the life cycle of silver perch can be closed. The use of domesticated broodfish will eliminate reliance on wild populations and provide a basis for future hatchery production and selective breeding programs.     

Designing a protocol to evaluate Crassostrea gigas spat production in hatcheries: Identification of critical aspects

The oyster Crassostrea gigas (Thunberg 1793) is one of the most important species for shellfish aquaculture worldwide, and many cultivation activities rely on the use of spat produced in hatcheries. The operation of hatcheries and the efficiency of the processes involved remain largely unknown. We designed a protocol to evaluate 31 elements of the different phases of C. gigas spat production to identify critical aspects. Our survey was conducted in four hatcheries located in Mexico. The results showed that hatcheries operate with an overall fair control of processes. Nonetheless, six critical control items and six below-average control items suggest that some practices are inappropriate for producing high-quality spat. For 16 items, at least one hatchery applies a suitable production process, but only for three items all hatcheries use the best alternative. Major concerns are the few oysters used in spawning processes, the lack of controlled crosses either between them or with other oyster lines, and the current lack of genetic tests. Besides, broodstock pedigree is not documented and the genetic variability of spat is unknown. Additional concerns are that hatcheries have no controls in place for gamete production estimates or for fertilization, hatching, settlement, and survival rates. The protocol seemed adequate to identify the major difficulties faced by hatcheries. These findings set the basis for the improvement of production processes in hatcheries. Potential areas deserving further research are also underlined.     

归化和异化策略在汉英新闻报道翻译中的应用

新闻报道是日常生活中常见的一种文体类型，就翻译而言，新闻报道有着不同于文学翻译的特殊性。归化和异化是文化翻译中常用的两大策略。从汉英新闻报道文化翻译的文本特点出发，研究归化和异化策略在汉英新闻报道翻译中的应用。     

匍枝委陵菜引种驯化试验

匍枝委陵菜（Potentilla flagellaris Willd.ex Schlecht. ）,又名蔓委陵菜、鸡头儿苗,为蔷薇科委陵菜属植物.分布于黑龙江、山东、山西、河北、甘肃、江苏,朝鲜、蒙古及俄罗斯西伯利亚地区也有分布.本文研究了野生地被植物匍枝委陵菜的生物学和生态学特性、物候特点、繁殖规律及开发利用价值.结果表明,匍枝委陵菜具有广泛的适应性和较强的抗逆性,生长快,繁殖力强,成坪时间短,绿期长,既可观叶又可观花,管理粗放,养护费用低,通过驯化和开发,可广泛应用于城市园林和绿化.     

白琵鹭的人工驯养

对7只野生白琵鹭雏鸟进行人工育雏试验的结果表明,白琵鹭雏鸟体重增长符合Richards方程W=A（1-Le^-bt)^c,体长增长符合Richards方程L=A（1-Le^-dt)^c其生长发展迅速,体长、嘴峰在80日龄时接近成体,跗,翅长,尾长在45-50日龄时接近成体,饲养期120天,育雏成功率达到100%。     

大理州野生矮杨梅生物学特性及驯化栽培研究

2001年在宾川县大营镇排营村的滴水箐，进行矮杨梅育苗及造林试验，面积8．8hm^2。1年后观察，成活率达90．7％，平均地径0．39cm，平均苗高13．39cm。对存在的问题进行了讨论，提出了改进意见。     

Indigenous Agroforestry Systems in Amazonia: From Prehistory to Today

Understanding the historical development of indigenous systems will provide valuable information for the design of ecologically desirable agroforestry production systems. Such studies have been relatively few, especially in Amazonia. The agroforestry systems in Amazonia follow a trail that begins with the arrival of the first hunter-gatherers in prehistoric times, followed by the domestication of plants for agriculture, the development of complex societies rich in material culture, the decimation of these societies by European diseases, warfare, and slavery, the introduction of exotic species, and finally, the present-day scenario of widespread deforestation, in which agroforestry is ascribed a potential role as an alternative land use. Despite the upheavals which occurred in colonial times, greatly reducing the population of native tribes, a review of anthropological and ethnobiological literature from recent decades indicates that a great variety of indigenous agroforestry practices still exist, ranging from deliberate planting of trees in homegardens and fields to the management of volunteer seedlings of both cultivated and wild species. These practices result in various configurations of agroforestry systems, such as homegardens, tree/crop combinations in fields, orchards of mixed fruit trees, and enriched fallows. Together they constitute a stock of knowledge developed over millenia, and represent technologies that evolved along with the domestication of native forest species and their incorporation into food production systems. This knowledge is the basis for the principal agroforestry practice employed by farmers in Amazonia today, the homegarden, and has potential to contribute to the development of other agroforestry systems.