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991.
在长江中下游平原湖区,棉花生长期间适逢雨季,常受多过程涝渍胁迫。通过测坑试验发现棉花受多过程涝渍胁迫后减产严重,涝渍程度可用涝渍因子(SFW、SEW50、SFEW50)来描述,棉花相对产量(Ry)与涝渍因子(SFW、SEW50、SFEW50) 之间存在着显著的线性关系。 相似文献
992.
Zhu Zizong Zhang Binghuai 《保鲜与加工》1998,(2):101-105
A series of experiments were carried out in the department laboratory and showed that using fixed bed jar method the coal base reduction of poor siderite can produce reduction ore.by ball milling and magnetic separation the sponge iron(TFe>80%,SiO 2<6%) was obtained.Thereby the scientific basis for developing and utilizing the low grade siderite were provided. 相似文献
993.
泥石流沉积与环境及其在防灾减灾上的意义 总被引:1,自引:0,他引:1
列出了5种泥石流沉积类型或亚相。A相:泥石流混杂层;B相;表泥层;C相:冲刷层;D相:底泥层;E相:泥层。一个沉积旋回的标准泥石流相序是始于D相,往上是A相、C相或B相,而C相是沉积间断的标志。泥石流沉积体随时间和空间有不同的分布和变化。在泥石流扇形地的不同部位,泥石流沉积相的系列与标准沉积相系列相比会有一定的差异,但保留主要因子。 相似文献
994.
高硫酸盐有机废水厌氧处理技术的进展 总被引:34,自引:2,他引:32
本文通过硫酸盐还原菌和产甲烷菌的竞争、硫化物对产甲烷菌的毒害二方面,论述了在高硫酸盐有机废水厌氧处理过程中,硫酸盐还原作用对产甲烷菌活性的抑制机理,同时,介绍了当前高硫酸盐有机废水的厌氧处理工艺 相似文献
995.
Hirofumi Hirai Ryuichiro Kondo Kokki Sakai Yoshio Watanabe Ryuichiro Kurane 《Journal of Wood Science》1999,45(3):262-265
The reduction of ferric chelate caused by various wood-rot fungi was analyzed. Ferric chelate reductive activity was detected in cell-free extracts of seven wood-rot fungi:Phanerochaete chrysosporium, P. sordida YK-624,Ganoderma sp. YK-505,Coriolus versicolor, Bjerkandera adusta, Tyromyces palustris, andGloeophyllum trabeum. These fungi produced NADPH- or NADH-dependent ferric chelate reductive enzymes (or both) of different molecular weight. In the liquid culture ofP. sordida YK-624 andC. versicolor, a positive correlation was observed between extracellular MnP activity and intracellular NADPH-dependent ferric chelate reductive activity. 相似文献
996.
由于其深刻的国际、国内背景的影响.我国关税自1986以来,先后进行了5次下调,这对促使人们更新观点、加速我国现代外贸体制的建立及提高我国在国际政治、经济舞台上的影响等产生了重大的政治效应。 相似文献
997.
V. K. Tchebotar U. G. Kang C. A. Asis Jr. S. Akao 《Biology and Fertility of Soils》1998,27(4):349-352
The gusA-marked Azospirillum lipoferum T1371, constructed by inserting transposon mTn5SSgusA20 from Escherichia coli S17-1 λ-pir into the genome of Azospirillum lipoferum 137, was used to evaluate its effect on nodulation of white clover with and without Rhizobium inoculation. When inoculated alone, Azospirillum colonized the tap roots, secondary roots and root hairs. The combined inoculation of white clover with Rhizobium leguminosarum bv trifolii and A. lipoferum enhanced the number of nodules by 2–3 times from 5 to 20 days after inoculation (DAI). The combined inoculation also enhanced
acetylene reduction activity by 2.3–2.7 times at 20 DAI. Moreover, Azospirillum was observed colonizing the tap root, root hairs and sites near or on the nodules. These results suggest that the formation
of additional infection sites by A. lipoferum, with a combined inoculation, may be the mechanism that will enhance nodulation and nitrogen fixation of white clover.
Received: 23 July 1997 相似文献
998.
Ethylene production and decomposition in soils 总被引:6,自引:0,他引:6
Six soils differing in texture and use were investigated for their ability to produce and decompose ethylene. In addition,
changes in methane and CO2 concentrations were monitored. The effects of organic amendments and different water tensions were studied, and a method
using low concentrations of acetylene as an inhibitor of ethylene degradation was tested. Possible reduction of acetylene
to ethylene was identified by the use of CO or NH4
+-N, of which the latter turned out to be the more reliable method. This reduction only occurred in a grassland soil. Under
aerobic soil conditions, gross ethylene production rates of up to 4.7pmol g–1 h–1 could be measured. Highest ethylene production and lowest ethylene decomposition was detected in a spruce forest soil. Fine
textured soils produced more ethylene than coarse textured soils. Amended soils produced more ethylene at –100kPa and –5kPa
than at 0kPa water tension. Ethylene decomposition was most effective in soils from deciduous woodlands and reached rates
of up to 137pmol g–1 h–1. Parallels between ethylene and methane decomposition were observed. The addition of 5mgg–1 glucose and 1mgg–1 methionine not only promoted ethylene production but also inhibited ethylene decomposition.
Received: 4 April 1997 相似文献
999.
中国某些水稻土中硝态氮向铵态氮的还原研究 总被引:2,自引:0,他引:2
Three paddy soils were examined for their capacities of dissimilatory reduction of nitrate to ammonium (DRNA). 15N-labelled KNO3 was added at the rate of 100 mg N/kg. Either glucose or rice straw powder was incorporated at the rate of 1.0 or 2.0 mg C/kg respectively. Three treatments were designed to keep the soil saturated with water: (1) a 2-cm water layer on soil surface (with beaker mouth open); (2) a 2-cm water layer and a 1-cm liquid paraffin layer (with beaker mouth open); and (3) water saturated under an O2-free Ar atmosphere. The soils were incubated at 28℃ for 5 days. There was almost no 15N-labelled NH4+-N detected in Treatment 1. However, there was 1.4 to 3.4 mg N/kg 15N-labelled NH4+-N in Treatment 2, and 2.1 to 13.8 mg N/kg in Treatment 3. Glucose was more effective than straw powder in ammonium production. Because there was sufficient amount of non-labelled NH4+-N in the original soils, 15N-labelled NH4+-N produced as such should be the result of dissimilatory reduction. Studies on microbial population showed that there were plenty of bacteria responsible for DRNA process (DRNA bacteria) in the soils examined, indicating that number of DRNA bacteria was not a limiting factor for ammonium production. However, DRNA bacteria were inferior in number to denitrifiers. The DRNA process in soil suspension started after 5 days of incubation. Glycerol and sodium succinate, though both are readily available carbon sources to organisms, did not facilitate DRNA process. DRNA occurred only when glucose was available and at a C:NO3--N ratio >12. Both availability and quality of the carbon sources affected DRNA. 相似文献
1000.
对虾养殖实验围隔中的固氮作用及其氮输入 总被引:2,自引:0,他引:2
1997年6~10月,以乙炔还原法进行了不同放养模式下对虾养殖实验中生物固氮作用的测定。结果表明,各围隔中,对虾单养(Y-4)和对虾+海湾扇贝(Y-5)的固氮作用较高,均值分别为2.62μgN/(L·hr)和2.65μgN/(L·hr);对虾+罗非鱼+缢蛏(T-5)的最低,为1.53μgN/(L·hr),对虾+缢蛏(Y-6)和对虾+罗非鱼(Y-7)的分别为2.30μgN/(L·hr)和1.89μgN/(L·hr)。各围隔中固氮速率较高与水体有效氮含量较低及有效氮磷比值不高有关。水层固氮蓝藻主要为蓝球藻(Chrococus)和念珠藻(Nostoc)。估算各围隔实验期间固氮作用输入分别为Y-4∶17.72g;Y-5∶19.63g;Y-6∶9.05g;Y-7∶10.59g;T-5∶7.99g。 相似文献