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51.
Two strains (derepressed-nitrogen fixing, Mac-27 and phosphate solubilizing, PS-21) of Azotobacter chroococcum were inoculated in fish culture ponds, singly and in combination with inorganic fertilizers (urea, single superphosphate–SSP). Physico-chemical parameters of pond waters, plankton production and fish biomass were studied. Inoculation of A. chroococcum (Mac-27) enhanced nitrogenase activity and rate of nitrogen fixation. A slight reduction in nitrogen fixation and nitrogenase activity was noticed when urea at 96 kg ha–1 y–1 was mixed with the biofertilizer (Mac-27). Inoculation of PS-21 enhanced phosphate solubilization, but Kjeldahl-nitrogen concentration values remained low in comparison with controls. On the other hand, inoculation of Azotobacter (either strain) enhanced the accumulation of ammonium-N, nitrite-N and nitrate-N. A significant (p < 0.05) reduction in dissolved oxygen (DO) concentration also took place when Azotobacter (both Mac-27 and PS-21) was inoculated in fish ponds. However, when used along with inorganic fertilizers, the reduction was not significant. The pH values were only slightly lowered when the phosphate-solubilizing strain (PS-21) of Azotobacter was inoculated. Inoculation of biofertilizer enhanced plankton production, net primary productivity and fish biomass. However, highest values in most of these parameters were noticed only in ponds that were treated with the higher doses of inorganic fertilizers (urea 192 kg and SSP 1500 kg ha–1 y–1). © Rapid Science Ltd. 1998 相似文献
52.
为了准确了解小麦品系中1BL/1RS易位系的存在,利用7 000多个DArT分子标记(Diversityarrays technology,多样性微阵列技术)对87个普通小麦品系进行扫描,总共获得1 750个稳定的多样性的分子标记(P>80)。这些标记的多态性信息含量指数(PIC)的范围是0.03~0.5,平均值为0.35(P>80)。根据DArT标记的可整合性,利用1B染色体上的DArT数据进行主坐标分析(Principal-Coordinates Analysis,PCoA),可以把实验材料划分为两个群,并且确定一个群是由1BL/1RS易位系组成,另一个群由非1BL/1RS易位系组成。同时,利用非加权组平均法(Unweighted pair-group method with arithmetic means,UPGMA)进行聚类分析,调查了材料之间的遗传关系,结果显示,实验材料同样聚集为两个群,一个群由1BL/1RS易位系组成,包含两个亚群;另一个群由非易位系组成,包含六个亚群。研究证实,DArT标记不仅可以调查小麦全基因组的遗传多样性,而且利用它的可整合性能够准确鉴定研究材料中的1BL/1RS易位系。 相似文献
53.
《Communications in Soil Science and Plant Analysis》2012,43(15):1960-1979
The mineral compositions of the fruit and tree parts of common guava, Psidium guajava L., and strawberry guava, Psidium cattleianum var. lucidum, were determined. The study occurred during three seasons at six locations in Hawaii to assess guava as feed for livestock. Guava bark contained the greatest concentrations of calcium (Ca) and ash; leaves the greatest concentrations of magnesium (Mg), sulfur (S), sodium (Na), boron (B), and manganese (Mn); and the shoots had the greatest concentrations of nitrogen (N), phosphorus (P), and potassium (K). The leaves and the shoots had the greatest concentrations of copper (Cu) and iron (Fe). Between guava and waiwi, guava had greater concentrations of most minerals except for Na in all plant parts, and Mg and ash in the leaves. Guava leaves and shoots meet the macromineral requirements for various phases of sheep, goat, and beef cattle life cycles with the exception of P and Na. Guava shoots do not meet Mn requirements for lactating cows. 相似文献
54.
黄荣莉 《农业图书情报学刊》2010,22(4):141-144
电子技术的发展,数字图书的出现,形成了阅读资源多元化发展的新趋势,使传统阅读资源受到强烈冲击和影响。虽然阅读的栽体在不断变化,但不变的是读者的需求,只要是有价值的资源,就是读者愿意接受的阅读资源。在相当长的时间内,传统阅读和数字阅读资源会优势互补、各显特色,共生共存。 相似文献
55.
浅谈科技论文写作之常见问题及对策 总被引:1,自引:0,他引:1
马鑫 《农业图书情报学刊》2011,23(2):175-177
针对目前科技论文写作中存在的摘要、关键词、引言、正文、结论、参考文献等不规范的问题进行简要描述,提出相应对策,并对盲目投稿问题提出自己的观点。以期对学术期刊的文章作者提供参考和帮助。 相似文献
56.
57.
选用3头三月龄左右装有瘤胃瘘管的荷斯坦公犊,按3×3完全拉丁方试验设计,喂给三种日粮,日粮组成按精粗比分别表示为:Ⅰ:70∶30;Ⅱ:60∶40;Ⅲ:50∶50,研究不同日粮组成下新疆芦苇的DM、CP以及NDF在断奶初期奶公犊瘤胃内动态降解。结果表明:精粗比为60∶40日粮时,其CP的消失率和降解参数显著低于精粗比为70∶30和50∶50的日粮(P<0.05);其DM和NDF的消失率和降解参数显著高于精粗比为70∶30和50∶50的日粮(P<0.05)。 相似文献
58.
This research was conducted to assess polymorphism among local genotypes of common fig available in Jordan (one of countries of origin). Leaf samples were collected in spring for DNA isolation from 20 different local genotypes (5 cultivars and 15 landraces). Two more wild types and one foreign cultivar were included. The genotypes were assessed using the randomly amplified polymorphic DNA (RAPD) technique. Six of the 19 screened primers showed reproducible polymeric profiles. Out of 62 amplified bands, 48 were polymorphic (77%). They generated 1104 data entries (591 for present and 513 for absent bands). After determining Jaccard similarity index, some genotypes showed high genetic similarity (90% between F20 and F22), while other were less similar (3–18% between F11 and all other genotypes). Moreover, the primers were evaluated for their discriminating power, where primer RAPD06 showed the weakest power (0.431), while highest values of 0.989 and 0.996 were achieved for primers RAPD02 and RAPD13, respectively. 相似文献
59.
60.
The interaction between landscape structure and spatial patterns of plant invasion has been little addressed by ecologists
despite the new insights it can provide. Because of their spatial configuration as highly connected networks, linear wetlands
such as roadside or agricultural ditches, can serve as corridors facilitating invasion at the landscape scale, but species
dynamics in these important habitats are not well known. We conducted a landscape scale analysis of Phragmites australis invasion patterns (1985–2002 and 1987–2002) in two periurban areas of southern Québec (Canada) focusing on the interaction
between the network of linear wetlands and the adjacent land-uses. Results show that, at the beginning of the reference period,
the two landscapes were relatively non-invaded and populations occurred mostly in roadside habitats which then served as invasion
foci into other parts of the landscape. The intrinsic rates of increase of P. australis populations in linear anthropogenic habitats were generally higher than those reported for natural wetlands. Riparian habitats
along streams and rivers were little invaded compared to anthropogenic linear wetlands, except when they intersected transportation
rights-of-way. Bivariate spatial point pattern analysis of colonization events using both Euclidian and network distances
generally showed spatial dependence (association) to source populations. An autologistic regression model that included landscape
and edaphic variables selected transportation rights-of-way as the best predictor of P. australis occurrence patterns in one of the landscapes. Given the high invasion rates observed, managers of linear wetlands should
carefully monitor expansion patterns especially when roads intersect landscapes of conservation or economic value. 相似文献