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21.
The study investigated diversity and frequency of occurrence of glomale (Arbuscular- or Vesicular Arbuscular-) mycorrhizal
fungi on three farming systems in a drought prone and nitrogen deficiency site in southern Malawi. The farming systems comprised
of two agroforestry systems of Sesbania sesban (L) Merr intercropped with maize and Sesbania macrantha E Phillips & Hutch. intercropped with maize and a maize monocrop systems without fertilizer, with nitrogen, phosphorus and
a combination of nitrogen and phosphorus. Species diversity and species frequency of occurrence were examined in soil samples
obtained in the dry and wet seasons. Twelve glomale mycorrhizal species were recorded, four species being in the genus Acaulospora, four in Glomus, two in Gigaspora and two in Scutellospora. Species diversity in the two agroforestry systems were not significantly (p ≤ 0.05) different but had lower species diversity than maize monocrop with only Sesbania macrantha intercropped with maize significantly (p ≤ 0.05) lower. Species diversity was significantly increased by the inorganic nitrogen fertilizer. Inorganic phosphorus fertilizer
had no effect. The study shows that the occurrence and persistence of glomale species are influenced by agroforestry combinations,
and that the spores of most species are tolerant to dry conditions. Only four species responded to fertilizer application
with the occurrence of spores of some species high and some low. Management practices have great implication in the persistence
of spore propagules of glomale species.
The order Glomale was revised in 2001 and upgraded to a phylum Glomeromycota. 相似文献
22.
Andrew W. Bruckner 《Aquarium Sciences and Conservation》2001,3(1-3):79-94
The extraction of coral reef organisms for the aquarium and curio trade is reported to be contributing to coral reef degradation. The total international trade and associated impacts are unknown, because data are collected only for organisms listed on Appendix II of CITES, which include stony corals, antipatharians and giant clams. CITES data indicate that trade in live stony coral and reef substrate (live rock) increased by 15–30% each year during the 1990s, with most exports since 1992 from Indonesia and Fiji. Overall, 19% of all stony coral traded (by item) from 1985 to 1997 was live; 71kern-1pt% of this was traded between 1993 and 1997 (52% of total trade). Although tracking trade using information from the CITES Trade Database provides limited information (e.g., coral is reported to genus, and volume is reported by item or weight), the CITES mechanism promotes the development of strategies to protect resources. In response to CITES requirements, Indonesia developed a management plan for sustainable harvest of corals, but not for non-CITES listed species such as soft corals and fishes. Trade in hard and soft coral provides revenue for developing countries; however, in order to be of lasting value the industry must be developed with a conservation ethic. This requires support for international programs such as CITES, management plans for sustainable harvest, and improved enforcement. 相似文献
23.
Due to taxonomic positions and special living environments, marine organisms produce secondary metabolites that possess unique structures and biological activities. This review is devoted to recently isolated and/or earlier described marine compounds with potential or established cancer preventive activities, their biological sources, molecular mechanisms of their action, and their associations with human health and nutrition. The review covers literature published in 2003–2013 years and focuses on findings of the last 2 years. 相似文献
24.
25.
南四湖的水生生物和渔业生态初析 总被引:3,自引:0,他引:3
南四湖是指位于山东省南部的微山、昭阳、独山和南阳四个湖,现有水面11.9万公顷。目前的平均鱼产量是94.05公斤/公顷。1983—1984 年我省对该湖进行了全面的渔业资源调查。南四湖的溶氧含量平均为 8.71毫克/升,pH为 7.1—9.7。湖水中的磷酸盐是0.0108毫克/升,三态氮是0.465 毫克/升。水生维管束植物的生物量是 2584.2毫克/米~2,浮游植物和浮游动物的平均生物量分别为1.709和0.601毫克/升,底栖动物的平均生物量是92.65克/米~2。鱼类的优势种类是鲫鱼、黄颡鱼、乌鳢、红鳍鲌、长春编、鲶鱼、鲤鱼。并为开发它们提出了初步建议。 相似文献
26.
水产食品特定腐败菌与货架期的预测和延长 总被引:25,自引:2,他引:25
Fresh fish and lightly preserved fish products are welcome by the global market, however, they are also among the most perishable food products. The research on specific spoilage organisms (SSO) reveals the spoilage process of aquatic product. This paper reviews the current knowledge (past ten years) on SSO of fresh fish and lightly preserved fish products with particular emphasis on characteristics of SSO and how to apply this concept to determine, predict and extend the shelf life of aquatic product. During storage, the microflora changes owing to different abilities of the microorganisms to tolerate the preservation conditions. SSO is defined as special microorganisms which can increase rapidly during preservation and has the ability to produce off- odours and off- flavours associated with spoilage, and spoilage metabolites. Identification of an SSO relies on comparison of the sensory and chemical characteristics of spoiled product with those of isolates from the spoilage microflora. Generally, the SSO of fresh fish may be a single species or genus, but the ones of lightly preserved fish products will be more complex. One exciting area for use of SSO aims to obtain quantitative knowledge about probable behavior of SSO and their function during the progression of spoilage. Thus mathematical models on the growth of SSO are established to evaluate the quality lost degree of product, which provide a sound information for the rational development of devices to monitor loss of products shelf life. Models for the growth of Pseudomonas spp, S. putrefaciens, P. phosphoreum have been established, and validated for shelf life prediction of seafood successfully. Another application field of SSO intends to develop the techniques to prolong the shelf life of food products by inhibiting SSO targetedly. Targeted inhibition of spoilage bacteria during preservation reduces their growth and results in a significant extension of shelf life in despite of the activity of non - spoilage organisms has not been influenced. Such techniques have been applied in perversion field of fresh fish and lightly preserved fish. 相似文献
27.
Rathindra Nath Mandal Kuldeep Kumar Utkal Laxmi Mohanty & Prem Kumar Meher 《Aquaculture Research》2007,38(13):1364-1369
This study examined the food organisms found in the gut of freshwater mussels, Lamellidens marginalis L. A total of 34 taxa of food organisms were recorded, out of which 30 taxa belonged to phytoplankton and four taxa to zooplankton. Both the groups comprised three families each: Cyanophyceae (blue‐green algae), Chlorophycea (green algae) and Bacillariophyceae (diatoms) constituted phytoplankton, whereas Euglenaceae, Chlamydodontidae and Brachionidae belonged to zooplankton. The total number of frequencies of phytoplankton (n=537) were almost nine times more than that of zooplankton (n=60). When blue‐green algae, green algae, diatoms and zooplankton (all the three families together) were tested for significant difference (P<0.05) following Duncan's multiple range test, the result showed only two groups. Blue‐green algae, green algae and zooplankton were not significantly different (P<0.05), forming group A, whereas diatoms were significantly different from others, forming group B. The present study showed that the maximum number of organisms that mussels feed upon belong to green algae, followed by diatoms, blue‐green algae and few taxa of zooplankton. 相似文献
28.
29.
Makoto Kimura 《Soil Science and Plant Nutrition》2005,51(2):159-181
As rice fields are managed for improved rice production, many studies on aquatic organisms in the floodwater have been restricted to agronomically important members such as blue-green algae (BGA) and Azolla , and ecological studies on common aquatic organisms were relatively limited to specific group members. In the present paper, studies on all the aquatic organisms in the floodwater, from protozoa to insects and fishes, were reviewed worldwide from the viewpoint of rice field ecology, paying attention to their populations, seasonal variations, antagonistic relations and biomass, and the effect of field management. Most studies conducted in India and in the Southeast Asian countries dealt with the BGA and green algal populations. In contrast, protozoa and aquatic animals were extensively studied in rice fields in Europe. Japanese studies in the past were intermediate between the previously cited studies. They generally described specific groups depending on the authors' interests, and surprisingly few studies dealt with the community level and prey-predator relationships. Field management such as fertilizer and pesticide application, water management and plowing was found to play a major role in determining the populations of aquatic organisms. Overview of research on aquatic organisms in the floodwater of rice fields suggests several directions for future studies. 相似文献
30.
Against the neoliberal steamroller? The Biosafety Protocol and the social regulation of agricultural biotechnologies 总被引:1,自引:0,他引:1
Through a discursive and organizational analysis we seek to understand the Biosafety Protocol and the place of socioeconomic
regulation of agricultural biotechnology in it. The literature on the Protocol has been fairly extensive, but little of it
has explored debates over socioeconomic regulation during the negotiation process or the regulatory requirements specified
in the final document. This case is especially important at a time when the spread of neoliberalism is increasingly associated
with deregulation, because it sheds light on the conditions under which circumvention of the market is deemed legitimate and
socio-economic regulation of agricultural technology is possible.
Daniel Lee Kleinman
is a professor in the Department of Rural Sociology at the University of Wisconsin, Madison, where he is also affiliated
with the Holtz Center for Science and Technology Studies and the Integrated Liberal Studies Program. He is the author and
editor of a number of books, including Impure Cultures: University Biology and the World of Commerce (2003).
Abby J. Kinchy
is a PhD candidate in the Departments of Sociology and Rural Sociology at the University of Wisconsin, Madison. Her current
research examines the controversies surrounding the genetic “contamination” of Mexican maize and Canadian canola. 相似文献