排序方式: 共有23条查询结果,搜索用时 188 毫秒
1.
[Objective] The study aimed to research the nutrients release of ponds sediment.[Method] The sediments which from a new pond(A) and an old one (B) these analyses used to carry out indoor experiment under the anaerobic dark condition for researching on nutrient release. The N(nitrogenous) and P(phosphorous) release were analyzed every two days.[Result] At the prophase, the N release in B was bigger than that in A, while the decline sediment release in A was gentle.[Conclusion] There was no accumulation of organic compound during the breeding time. The NH4-N was the main form of N release; and the P release was correlated with N release, while PO4-P was the main form of P release. 相似文献
2.
利用RAPD分子标记分析了江黄颡(♀)和乌苏里拟鲿(♂)及其杂交子代3个群体的遗传结构。18个RAPD随机引物对每个群体8尾鱼的基因组DNA进行扩增,共获得106个条带清晰且重复性较好的RAPD标记,片段大小在200~2 000 bp之间,江黄颡(♀)和乌苏里拟鲿(♂)及其杂交子代3个群体的多态位点比例分别为17.92%、18.87%和25.47%,平均遗传相似系数分别为0.940 8、0.936 8和0.928 0,平均遗传距离分别为0.059 2、0.063 2和0.072 0,平均Nei’s基因多样性指数(H)分别为0.075 4、0.073 8和0.103 6,平均Shannon信息指数(I)分别为0.108 7、0.108 1和0.150 1;亲缘关系树状图显示杂交子代与母本遗传距离较近,而与父本遗传距离较远。结果分析表明:杂交子代继承了双亲的优良性状,但从母本中继承的遗传物质稍多于父本;杂交子代群体内的遗传多样性高于两亲本群体,杂交一代基因杂合性增强,表现出一定的杂种优势。 相似文献
3.
孙美萍 《北京林业大学学报》2012,(Z1):5-6
<正>与无锡文明史结缘最早的植物,是梅;与无锡太湖山水结缘且最早蔚然大观的植物,是梅;在无锡近代史上,由我国民族工业先驱荣氏兴建的第一座太湖近代园林,其所使用的主题植物材料,仍然是梅。公元前12世纪,崛起在今陕西岐山、渭水一代的周部落,出了一位据称能使该部落走向光辉顶点但当时还是婴儿的姬昌。这样姬昌的伯父泰伯、仲庸为了避免王位的纷争,便南奔荆蛮,在一个叫作"梅里"的地方,建立了人口仅千余家的小方国,名"勾吴"。姬昌,就是后来的周文王;勾吴,则是此后强大的春秋吴国的 相似文献
4.
该文研究了在疲劳/蠕变交互作用下竹木复合层合板的断裂损伤行为.结果表明,在交变载荷最大值为竹木复合层合板破坏载荷的75%时,其疲劳/蠕变断裂曲线为三段式曲线;在交变载荷最大值为破坏载荷的55%时,6h内其疲劳/蠕变曲线为两段式曲线.随着蠕变时间的增加,层合板的断裂寿命降低.在交变载荷最大值为破坏载荷的75%时,蠕变时间为300s时,层合板的疲劳/蠕变负交互损伤程度大于蠕变时间为180s的.疲劳/蠕变交互作用下层合板的破坏形式主要为纤维撕裂、界面剪切破坏和层间开裂3种形式的综合表现. 相似文献
5.
全球化不仅带来了世界政治和经济格局的变化,而且也改变了生物分布的空间格局——导致生物种群的重新分布,由此而产生的生物入侵已成为各国政府、国际社会和学术界所共同关心的全球变化问题。生物入侵、全球变化和生境丧失是21世纪的最棘手的三大环境问题。本文简述了生物入侵的概况、定义、入侵途径和过程,特别是其对农业生态系统的稳定性的影响,在此基础上提出了一些防止生物入侵的治理方法和策略。 相似文献
6.
长江徐六泾段渔业水环境现状初步调查 总被引:4,自引:0,他引:4
2005年12月至2006年9月对长江徐六泾段渔业水域水质现状进行了调查,采用均值型环境污染评价法,参照渔业水质标准(GB11607-89)和地表水环境质量标准(GB3838-2002及GBZB1-1999)确定水体污染程度。结果表明,在所选监测指标范围内,主要污染物类型为:总氮,综合质量指数为0.60,表明该江段水属轻度污染。 相似文献
7.
8.
9.
10.
Preliminary Studies on Antifungal Activity of Xanthium sibiricum and the Endophytic Fungi 总被引:4,自引:0,他引:4
QI Li-yan LIU Li-li YU Ping-ru CHEN Feng-mei .Forest station of Wuxi Agroforestry Bureau Wuxi .Key Laboratory of Biotechnology for Medicinal Plant of Jiangsu Xuzhou Normal University Xuzhou 《(《农业科学与技术》)编辑部》2008,(4)
[Objective] The study was aimed to provide theoretical foundation for developing a new fungicide with high activity,low toxicity and low residua.[Method] Based on the plant growth rate and inhibition zone methods,the antifungal activity of extracts of every organ of Xanthium sibiricum,the fermentation liquid of endophytic fungi MC4-23,and the extract of mycelium were tested with six kinds of pathogenic fungi and three kinds of pathogenic bacteria respectively.[Result] The extract of every organ of Xanthium sibiricum,the fermentation liquid of endophyic fungi MC4-23,and the extract of mycelium all had antifungal activities.The acetone extracts of Xanthium sibiricum had stronger antifungal activities than the ethanol extracts of Xanthium sibiricum.The extracts of leaf have the strongest antifungal activities against fungi and bacteria.The inhibition rates of the six pathogenic fungi were all above 47.8%,and the inhibition diameters of the three pathogenic bacteria were all above 0.5 centimeter.The fermentation liquid of endophytic fungi also had strong activities against the fungi and bacteria.The inhibition rates of the six pathogenic fungi were all above 68.1%.The extracts of root of Xanthium sibiricum and the mycelium of endophytic fungi were all had antifungal activities.[Conclusion] Xanthium sibiricum and endophyic fungi MC4-23 had great value of development and utilization. 相似文献