首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
This review paper describes a novel approach to plant cultivation under soil-less culture. At present, global climate change is expected to raise the risk of frequent drought. Agriculture is in a phase of major change around the world and dealing with serious problems. In future, it would be difficult task to provide a fresh and clean food supply for the fast-growing population using traditional agriculture. Under such circumstances, the soil-less cultivation is the alternative technology to adapt effectively. The soil-less system associated with the Hydroponic and Aeroponics system. In the aeroponics system, plant roots are hanging in the artificially provided plastic holder and foam material replacement of the soil under controlled conditions. The roots are allowed to dangle freely and openly in the air. However, the nutrient rich-water deliver with atomization nozzles. The nozzles create a fine spray mist of different droplet size at intermittently or continuously. This review concludes that aeroponics system is considered the best plant growing method for food security and sustainable development. The system has shown some promising returns in various countries and recommended as the most efficient, useful, significant, economical and convenient plant growing system then soil and other soil-less methods.  相似文献   

3.
During the past 10-15 years, sustainable agriculture has progressed from a focus primarily on a low-input, organic farming approach with a major emphasis on small fruit or vegetable production farms, often described as Low Input Sustainable Agriculture, to the current situation where sustainability is an important part of mainstream animal and plant production units. The US Department of Agriculture programmes cover a broad range of activities, including conserving the natural resource base, enhancing environmental quality, and sustaining productivity of the nation's farms. The use of Geographic Information Systems technology to direct application of fertilisers, pesticides, and herbicides is one example of a rapidly emerging technology that can reduce use of external inputs, protect the agricultural environment, and improve economic returns. This Geographic Information Systems technology also is being used to localise animal pest and disease problems, assist in regulatory or control measures, and identify high risk areas that might need different management systems or should be avoided as sites for animal production. Use of intensive grazing systems also has increased markedly over the past 5-6 years. These systems will allow longer grazing seasons in southern parts of the USA, provide more efficient use of the forages being produced and reduce labour costs in the typical dairy operation. Major animal and plant production agriculture-oriented programmes at the US Department of Agriculture focus on integrated production systems, use of Integrated Pest Management techniques, and development of alternative methods to manage pests and diseases that reduce or avoid the use of drugs and chemicals. The US Department of Agriculture has a programme for sustainable agriculture, the Sustainable Agriculture Research and Education programme, which emphasises alternative approaches for animal and plant production systems.  相似文献   

4.
Cellulase assay methods: a review   总被引:1,自引:0,他引:1  
  相似文献   

5.
On the basis of fundamental investigations in radiobiology, numerous methods of using ionizing radiations in agricultural practice have been proposed. The current status of the problem, on the basis of basic, semi-production and industrial-scale tests of the suggested methods, is described. We conclude that there is now a satisfactory, economically viable radiation-biology technology. For wide introduction of this technology into agricultural practice, governmental decisions concerning the production of specialized equipment, training of service personnel and overall organization of the work under production conditions are required.  相似文献   

6.
7.
土壤生物与可持续农业研究进展   总被引:1,自引:0,他引:1  
农业的可持续发展是人类文明持续繁荣的重要保障。从原始农业到工业化农业的发展历程,是"自然力"不断削弱,"人为调控力"不断加强的过程。新兴的可持续农业,则希望将人为调控和自然过程协调融合,建立近自然的高效的现代农业体系。但是,面对土壤生物极高的多样性、生物和非生物过程的复杂互作及其高度的时空异质性,基于还原论的传统科学研究方法探究地下生态系统的"自然过程"困难重重。人为管理措施对农田生态过程调控的针对性和调控效果受到极大限制。尽管如此,土壤生物在生态系统服务中的作用已在世界范围内得到空前重视。如何充分发挥土壤生物在可持续农业中的作用,已成为现代农业研究领域的重要突破口。简述了土壤生物与可持续农业研究的学科发展历史,总结了农业管理措施对土壤生物及土壤食物网特征的影响,突出了土壤生物群落在可持续农业模式中土壤结构改善、土壤肥力提高和化肥农药减施等方面的积极作用;最后探讨了当前的研究难点和未来的研究方向,并对如何充分发挥土壤生物在现代农业中的贡献进行了初步的思考。认为:土壤有机质,土壤结构和土壤食物网以及三者的内在联系是可持续农业研究的关键。土壤有机质管理是调控土壤结构、土壤食物网及生态系统生...  相似文献   

8.
New developments in different branches of biotechnology are discussed. The production of peptide hormones, new interferons and other lymphokines by the microbial and cell cultures, and new enzyme inhibitors of microbial origin are the most important for health care and pharmacy. The main direction in research in the agriculture represents the development of the new, very effective methods of nitrogen fixation and the production of animal growth hormones by genemanipulated microorganisms. One of the most important field of application of biotechnology is the chemical industry, c.f. microbial production of polymers and biotransformation of compounds previously produced by chemical methods (acrylamide, adipic acid, naphtalen conversion, etc.). Several novel methods of degradation of the cellulosic materials are mentioned and exploitation of biotechnology in environmental protection is also discussed.  相似文献   

9.
空间环境中的特殊因素会导致航天员肠道菌群及其代谢产物的失调,对机体会产生系统性的生理影响。本文综述了近年来太空飞行/模拟空间环境对肠道菌群及其代谢产物影响的研究进展。太空飞行/模拟空间环境(space flight/simulated space environment,SF/SPE)可导致侵袭性致病菌的增多及有益菌的减少,肠道炎症加剧与通透性增加,也会引起菌群的有益代谢物减少或有害代谢物增加,进而导致机体内代谢的紊乱,或可诱发其他系统的损伤,从而不利于航天员的健康与工作效率。总结太空飞行/模拟空间环境对肠道菌群产生的影响,可为该领域的后续研究与航天员的在轨健康防护提供科学依据。  相似文献   

10.
11.
The sporangiophore of the fungus Phycomyces bends away from nearby objects without ever touching them. It has been thought that these objects act as aerodynamic obstacles that damp random winds, thereby generating asymmetric distributions of a growth-promoting gas emitted by the growth zone. In the interest of testing this hypothesis, we studied avoidance in an environmental chamber in which convection was suppressed by a shallow thermal gradient. We also controlled pressure, temperature, and relative humidity of the air, electrostatic charge, and ambient light. A protocol was established that yielded avoidance rates constant from sporangiophore to sporangiophore to within +/- 10%. We found that avoidance occurred at normal rates in the complete absence of random winds. The rates were smaller at 100% than at lower values of relative humidity, but not by much. Remarkably, at a distance as great as 0.5 mm, avoidance from a 30-micron diam glass fiber (aligned parallel to the sporangiophore) was about the same as that from a planar glass sheet. However, the rate for the fiber fell more rapidly with distance. The rate for the sheet remained nearly constant out to approximately 4 mm. We conclude that avoidance depends either on adsorption by the barrier of a growth-inhibiting substance or emission by the barrier of a growth-promoting substance; it cannot occur by passive reflection. Models that can explain these effects are analyzed in the Appendix.  相似文献   

12.
环境水体微囊藻毒素微生物降解技术研究进展   总被引:3,自引:1,他引:3  
湖库水体富营养化及其产生的藻毒素污染已对生态环境和人类健康构成极大威胁,而目前常规水污染控制技术存在一定的局限性,因此水环境中藻毒素处理新工艺亟待研发.鉴于环境水体中的微囊藻毒素可被微生物降解为无毒或低毒的中间产物,本文综述了微囊藻毒素的降解菌株、生物降解过程影响因素与机理、降解产物及其结构特性等,总结了目前微囊藻毒素降解菌株在水环境修复中的应用,并对今后微生物降解微囊藻毒素的研究方向进行了展望,以期为解决我国日益严峻的湖库水体藻毒素污染和饮用水安全问题提供技术思路.  相似文献   

13.
14.
作为环境中广泛存在的污染物,微塑料(microplastics)的相关研究备受关注。基于已有研究,本文综合分析了微塑料与土壤微生物(soil microorganisms)的互作关系,微塑料会通过直接或间接的方式影响微生物群落结构与多样性,影响的程度取决于微塑料的类型、剂量和形状。土壤微生物会通过形成表面生物膜和群落选择效应来适应微塑料这一外来物所引起的变化。本文还特别关注了微塑料的生物降解机理,同时探究了影响这一过程的因素,微生物首先会定殖在微塑料表面,分泌多种胞外酶在特定位点发挥作用,将聚合物转化成低聚物或单体,解聚的小分子进入胞内进一步分解代谢,而影响这一降解过程的因素除了分子量、密度、结晶度等微塑料自身理化性质,还包括一些生物因素和非生物因素对相关微生物生长代谢和酶活性的作用。未来研究应注重与实际环境的联系,在深入探究微塑料生物降解研究的同时,开发解决微塑料污染问题的新技术。  相似文献   

15.
城市三维空间形态的热环境效应研究进展   总被引:2,自引:0,他引:2  
周伟奇  田韫钰 《生态学报》2020,40(2):416-427
城市的三维空间形态,通过影响地表能量平衡过程和空气流动,改变城市内部热环境,并可能加剧城市热岛效应。在三维空间上定量解析格局-过程-效应关系对于城市生态安全和可持续发展具有重要意义,可为城市生态规划与景观设计提供重要科学依据。从城市三维形态的热环境效应研究角度,综述了城市三维形态的定量化研究进展;总结了城市三维形态对热环境以及空气流动、太阳辐射等过程的影响;分析了当前城市三维形态的热环境效应研究领域存在的不足。未来的研究应注重建筑与植被三维特征的综合表征,三维形态指标的选择应综合考虑其对设计规划的指导作用,并加强城市三维形态对热环境影响机理及其尺度效应的研究。  相似文献   

16.
抗性基因在环境中的垂直及水平传播,致使抗生素耐药性成为危及人类和动物生命健康的全球性问题。动物源食品是中国美食不可或缺之物,而由于抗生素超用与滥用等行为让公众不得不关注动物源食品源头——养殖场的抗生素抗性基因环境安全问题。本文综述了养殖环境中抗生素抗性基因的研究进展,分析了养殖环境中抗生素抗性基因产生原因、传播途径以及影响因素,介绍了现有风险评估方法和控制技术,并对今后养殖环境中抗生素抗性基因的控制策略、技术及研究方向提出了建议。  相似文献   

17.
Nanotechnology is set to impact a vast range of fields, including computer science, materials technology, engineering/manufacturing and medicine. As nanotechnology grows so does exposure to nanostructured materials, thus investigation of the effects of nanomaterials on biological systems is paramount. Computational techniques can allow investigation of these systems at the nanoscale, providing insight into otherwise unexaminable properties, related to both the intentional and unintentional effects of nanomaterials. Herein, we review the current literature involving computational modelling of nanoparticles and biological systems. This literature has highlighted the common modes in which nanostructured materials interact with biological molecules such as membranes, peptides/proteins and DNA. Hydrophobic interactions are the most favoured, with π-stacking of the aromatic side-chains common when binding to a carbonaceous nanoparticle or surface. van der Waals forces are found to dominate in the insertion process of DNA molecules into carbon nanotubes. Generally, nanoparticles have been observed to disrupt the tertiary structure of proteins due to the curvature and atomic arrangement of the particle surface. Many hydrophobic nanoparticles are found to be able to transverse a lipid membrane, with some nanoparticles even causing mechanical damage to the membrane, thus potentially leading to cytotoxic effects. Current computational techniques have revealed how some nanoparticles interact with biological systems. However, further research is required to determine both useful applications and possible cytotoxic effects that nanoparticles may have on DNA, protein and membrane structure and function within biosystems.  相似文献   

18.
Systems healthcare is a holistic approach to health premised on systems biology and medicine. The approach integrates data from molecules, cells, organs, the individual, families, communities, and the natural and man-made environment. Both extrinsic and intrinsic influences constantly challenge the biological networks associated with wellness. Such influences may dysregulate networks and allow pathobiology to evolve, resulting in early clinical presentation that requires astute assessment and timely intervention for successful mitigation. Herein, we describe the components of relevant biological systems and the nature of progression from at-risk to manifest disease. We illustrate the systems approach by examining two relevant clinical examples: Alzheimer’s and cardiovascular diseases. The implications of systems healthcare management are examined through the lens of economics, ethics, policy and the law. Finally, we propose the need to develop new educational paradigms to enhance the training of the health professional in an era of systems medicine.  相似文献   

19.
20.
聚对苯二甲酸乙二醇酯(polyethylene terephthalate,PET)是应用最广泛的合成聚酯之一。由于PET不易降解,在环境中积累,对陆地、水生生态系统以及人类健康构成严重威胁。基于生物酶催化的生物降解策略为PET回收利用提供了一种绿色途径,在过去20年间,已发现了多种PET水解酶,并通过蛋白质工程等手段来改善这些酶的降解性能,但是目前仍未找到适合大规模工业应用的PET水解酶。利用传统的检测方法筛选PET水解酶是一个缓慢而复杂的过程。为了促进PET酶法回收的工业化应用,需要研发高效的检测方法。近年来,研究人员开发了多种表征PET水解酶的分析方法。本文总结了可用于筛选PET水解酶的检测方法,如高效液相色谱法、紫外吸光度法和荧光激活液滴分选法等,并对其在筛选PET水解酶的应用方面进行了展望。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号