EXPLANT AXENISATION FOR TISSUE CULTURE IN MARINE MACROALGAE     

刘学武  Bernard Kloareg 《中国海洋湖沼学报》1992,(3)

Unialgal explants from Luminaria digitata, and from a variety of red algae were obtained by hand removing the visible epiphytes, and stirring the tissue in the presence of glass beads. Two antibiotic mixtures were found to be efficient in removing the contaminating fungi and bacteria from the algae. The procedure proved suitable as a primary step in the tissue culture of the investigated species.  相似文献   

Making space for unruly water: Sustainable drainage systems and the disciplining of surface runoff     

Phil Jones  Neil Macdonald 《Geoforum》2007,38(3):534-544

This paper explores the disciplining of non-human actors through the example of sustainable drainage systems (SuDS) managing surface water runoff. The lens of performativity is used to examine the move from pre-modern repressive forms of discipline, to mechanisms which attempt a more productive disciplinary engagement by finding space to reform water’s more unruly behaviours. After examining the problems with traditional disciplinary approaches to water of rapid transit and exile, the paper explores the implications of a move towards SuDS technology. This change is examined using a case study of Glasgow, Scotland, where there is an attempt to utilise less repressive disciplinary mechanisms and to find spaces in the city for surface water outside the hard drainage infrastructure. New approaches to the disciplining of urban water are conceptualised as being a performance of tension between water and those who would modify its behaviour.  相似文献   

The role of human interventions in tree dynamics and environmental rehabilitation in the Sahel zone of Niger     

M. Larwanou  M. Saadou 《Journal of Arid Environments》2011,75(2):194-200

A study was conducted in 15 village territories of 3 regions in Niger. Among these sites, 4 were control and 11 had interventions comprising of farmer-managed tree natural regeneration (FMNR), water harvesting techniques (WHT) and windbreaks. The objective of the study was to determine the state of tree vegetation in terms of species diversity and harvestable volume and evaluate the environmental trend in the sites. An inventory of the vegetation was carried out during the rainy season using radial transects from the village centre, outwards, in addition to surveys with local communities.The results showed that tree diversity is enhanced in sites with interventions, and soil rehabilitation techniques and farmer-managed tree natural regeneration favor the rehabilitation and development of trees. The number of resprouts/seedlings varied with site, soil type and intervention. The number of harvestable trees depended on factors like caring, monitoring of cutting, types of intervention and ecological zone.Harvestable volume is a function of high regeneration rate, number of harvestable individual trees and site. Vegetation is improving in all the sites and local communities using tree products for their various needs. This study contributed to setting up a reference database for these sites.  相似文献   

Patterns and cellular mechanisms of arm regeneration in adult starfish Asterias rollestoni bell     

Tingjun Fan  Xianyuan Fan  Yutang Du  Wenjie Sun  Shaofeng Zhang  Jiaxin Li 《中国海洋大学学报(英文版)》2011,10(3):255-262

To understand the mechanisms of starfish regeneration, the arms of adult starfish Asterias rollestoni Bell were amputated and their regeneration patterns and cellular mechanisms were studied. It was found that cells in the outer epidermis and inner parietal peritoneum near the end of the stump began to dedifferentiate 4 d after amputation. The dedifferentiated cells in the outer epidermis proliferated,migrated to the wound site and formed a thickened pre-epidermis which would then re-differentiate gradually...  相似文献   

Explant exenisation for tissue culture in marine macroalgae   总被引：1，自引：0，他引：1  

Liu Xuewu  Bernard Kloareg 《中国海洋湖沼学报》1992,10(3):268-275

Unialgal explants fromLaminaria digitata, and from a variety of red algae, were obtained by hand removing the visible epiphytes, and stirring the tissue in the presence of glass beads. Two antibiotic mixtures were found to be efficient in removing the contaminating fungi and bacteria from the algae. The procedure proved suitable as a primary step in the tissue culture of the investigated species.  相似文献   

一种兼顾ArcGIS图形显示的AutoCAD图案填充重生成边界法     

韦胜  周生元 《测绘与空间地理信息》2015,(4):135-137

通过对现有AutoCAD图案填充重生成边界方法总结,提出了一种兼顾ArcGIS图形显示的AutoCAD图案填充重生成边界法,其主要包括3个步骤:1提取边界环并做循环访问;2对组成每个边界环的曲线集合按照起点和终点坐标进行排序;3对排序后的曲线集合进行连接。  相似文献   

Exploring the relationships between post-fire vegetation regeneration dynamics,topography and burn severity: A case study from the Montane Cordillera Ecozones of Western Canada     

《Applied geography (Sevenoaks, England)》2015

In this study the relationships between vegetation regeneration dynamics to topography and burn severity for a Canadian landscape were investigated using freely available Earth Observation (EO) imagery from Landsat TM sensor. The Okanagan Mountain Park, located in the Montane Cordillera Ecozones of Western Canada at which a fire occurred in 2003, was used as a case study. First, vegetation regeneration dynamics were quantified for a period of 8 years following the fire event based on a chronosequence analysis of the Normalized Difference Vegetation Index (NDVI) and the Regeneration Index (RI). The spatio-temporal patterns of post-fire NDVI from each image date were statistically compared to the pre-fire pattern to determine the extent to which the pre-fire spatial pattern was re-established and also the rate of recovery. Subsequently, the relationships of vegetation regrowth to both topography and burn severity was quantified using a series of additional statistical metrics. Burn severity was derived from the differenced Normalized Burn Ratio (dNBR) index computed from the Landsat TM images. Information on topography properties of the region was obtained from the ASTER global operational product.NDVI and RI analysis indicated a moderate vegetation recovery to pre-fire patterns, with regeneration to over 60% of the pre-fire levels 8-years after the fire. Regression analysis of pre- and post-fire mean NDVI exhibited significant re-growth in the first 3 years after the fire with a more gradual return in later years (an increase of 0.400 in R² by 2006 compared to only an increase of 0.129 for the subsequent 5 years). Re-growth rates appeared to be somewhat higher in north-facing slopes in comparison to south facing ones. As expected, NDVI decline due to fire was positively correlated with burn severity class, whereas negative correlation was found between damage and regeneration ability (recovery after 3 years = low severity 64%/high severity 58%, recovery after 8 years = low severity 72%/high severity 70%). To our knowledge, this study is one of the few attempting to explore the interrelationships of post-fire vegetation regrowth, topography and burn severity, especially in the case of a single large fire. RI based on control plots provides a valuable tool to quantify fire impact and subsequent vegetation regrowth. Furthermore, indication of burn severity is useful for strategically rehabilitating areas of slow or unsuitable post-fire vegetation recovery. This study corroborates the significance of EO technology as a successful and cost-effective solution in providing information related to economic and environmental post-fire regeneration assessment.  相似文献   

不同林龄人促更新林枯枝落叶层碳及养分贮量   总被引：1，自引：0，他引：1  

王小红  张金凤  林开淼  卢正立  曾宏达  郭剑芬 《亚热带资源与环境学报》2015,(1)

对福建南平顺昌县不同林龄米槠(Castanopsis carlesii)人促更新林枯枝落叶层和主要营养元素现存量进行测定,探究其随林龄的变化趋势。结果表明:不同林龄米槠人促更新林枯枝落叶层现存量为3.94~4.95 t·hm-2,其中49 a生人促林枯枝落叶层现存量最小,31 a生的最大。不同林龄枯枝落叶层C、N、P、K的浓度分别为44.09%~47.46%,11.9~13.8 g·kg-1,0.5~0.9 g·kg-1,1.4~5.1 g·kg-1。21 a生和49 a生人促更新林枯枝落叶层C浓度明显高于31 a生林分。49 a生人促更新林枯枝落叶层N和P浓度均高于21 a生和31 a生林分,但该林分枯枝落叶层K浓度却最低。21 a生米槠人促更新林枯枝落叶层C贮量分别是31 a生和49 a生林分的1.03倍和1.23倍,49 a生米槠人促更新林K贮量远低于21 a生和31 a生。不同林龄枯枝落叶层碳和养分贮量差异与林分特征、各林分枯枝落叶层现存量及养分浓度等有关。  相似文献   

广东清远市再生有色金属产业集群成长动力机制     

金利霞  李郇*  张虹鸥 《热带地理》2013,(3):314-323

从资源、市场、政策、产业转移等角度,结合区位熵、半结构式企业访谈和案例分析等定量与定性研究方法,探讨清远市再生有色金属产业集群的发展历程、现状、存在问题及其成长机制,提出在产业集群的演化过程中,其成长的动力机制随着经济和社会环境的变化也在不断地演变。在产业集群的形成初期,除了传统要素外,历史偶然性和市场自发性为集群的产生提供了可能性;而在中后期,政府作为制度的提供者在集群的发展和演变中扮演着重要角色。具体而言,巨大的有色金属再生资源蓄积量和庞大的劳动力资源等内生资源优势,加上政府对再生资源产业和集群的政策扶持、跨区域产业转移的制度安排、有意识地引进和培育龙头企业等外生制度优势,内源和外源动力共同促成高端要素的集聚发展、产业集群转型升级、集群化生产网络和专业化分工的形成。这种欠发达地区经济崛起的内生性推动力,能为其他城市发展再生资源产业提供重要的经验借鉴。  相似文献   

Adsorption–Reduction Behavior of Co(NH3) on Activated Carbon     

Yan‐Peng Mao  Yu Chen  Jing‐Yi Cheng  Hai‐Song Zhu  Xiang‐Li Long  Wei‐Kang Yuan 《洁净——土壤、空气、水》2012,40(2):117-122

A novel method has been put forward to retrofit the wet ammonia desulfurization process to realize the combined removal of sulfur dioxide and nitric oxide by introducing soluble cobalt(II) salt into aqueous ammonia solution. The active constituent of scrubbing NO from the flue gases is the produced by ammonia coordinating with Co²⁺. The regeneration of can be realized under the catalysis of activated carbon so as to sustain a high NO removal efficiency for a long time. In this paper, the adsorption–reduction behavior of on activated carbon has been researched using scanning electron microscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy. A conclusion can be drawn from the results that cobalt ions in the aqueous solution are adsorbed by activated carbon and most of them are reduced to Co²⁺ ions, and some of the Co²⁺ ions are further reduced into metallic cobalt. The results also demonstrate that the functional groups on the surface of carbon take part in this redox reaction. The C? H groups on the carbon surface are oxidized into C? OH, and then some of the hydroxyl groups are further oxidized into carbonyl or carboxyl groups.  相似文献