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白蚁肠道可培养菌群及其功能初探 总被引:2,自引:0,他引:2
白蚁是一种危害严重的昆虫,其以破坏木质而家喻户晓.文献表明,白蚁对木质强大的消化能力很大程度上取决于其肠道微生物的影响.为了探究白蚁肠道微生物的类群,本试验以黑翅土白蚁为材料,分离纯化获得其肠道主要可培养微生物的纯培养112种,其中喜氧菌35种,厌氧菌77种;在分离出的微生物类群中,通过刚果红法初步筛选出12种喜氧菌菌株可能具有纤维素酶活性,其最大透明圈达到4.0㎝×4.0㎝;进一步检测这些菌株的纤维素酶活性发现,12株菌均具有羧甲基纤维素钠盐(CMC-NA)酶活性和滤纸酶活性,但是大部分菌株羧甲基纤维素酶活性较弱,而一些菌株如 NBY14滤纸酶活较高,可达到16.188u/mL.试验结果可为黑翅土白蚁防治提供依据,亦可为纤维素酶的开发利用奠定基础. 相似文献
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Tracy Z. Dawes 《Soil biology & biochemistry》2010,42(10):1825-1834
Soil degradation is a major source of ecological dysfunction in both natural and agricultural landscapes. Termites are key mediators of tropical soil structure and function, but there has been little experimental evaluation of their potential in soil rehabilitation. This study investigated if termite activity can be used as a tool to improve the properties and function of degraded soil in tropical Australia, through mulch addition. A 2 × 2 randomised block design was used, with mulch (bare [B] or mulched [M] plots) and termiticide (termite [T] or non-termite [NT] plots) as factors. Over 4.5 years I tested the hypothesis that the MT plots would show greatest increase in (i) soil macroporosity, (ii) total soil surface carbon and nitrogen, (iii) litter decomposition, (iv) soil water storage and (v) plant cover, and (vi) greatest reduction in soil strength. MT treatment plots showed a 46% and 45% increase in soil macroporosity and plant cover, respectively, and a 25% reduction in soil strength compared with MNT plots. Compared with B treatments (BT, BNT), macroporosity and plant cover were 98% and 60% higher, respectively and soil water storage increased by up to 15%. Termites contributed to 58% of litter loss in MT plots over the transitional/dry season period. Mulching doubled soil carbon and nitrogen levels. This research demonstrates termite-mediated processes can be initiated and maintained in degraded soil, thereby improving soil structure and key ecosystem functions. Termites may represent a valuable biological resource for promoting tropical soil restoration, through incorporating techniques that promote their activity into tropical soil rehabilitation management. 相似文献
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Rates of dung decomposition and the associated accumulation of soil transported to the surface were compared for dung deposited during a dry and a wet season in a Costa Rican pasture. Average decomposition rates for the first 140 days after deposition were significantly lower for dung patches deposited at the beginning of the dry season than for patches deposited at the beginning of the wet season (0.73 vs. 1.50 g/day-1 on a dry weight basis). A strong linear relationship was found between dung removal and soil accumulation at the original soil surface, with an average of 2.0 g soil accumulated for every gram of dung which was removed. This relationship was not affected by deposition season. The lack of a seasonal difference, along with the relatively low decomposition rates during the wet season, were explained by the dominance of termites in the dung patches throughout the year. Evidence of dung beetle activity was never recorded during the dry season and was found in only 18 of the 45 dung patches recovered during the wet season. 相似文献
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By definition ‘ecosystem engineers’ are those organisms capable to modify physically the environment by producing ‘biogenic’ structures (BS). Large macroinvertebrates like termites, earthworms and ants produce BS with distinguishable physico-chemical properties. We measured total Corg, and contents in the BS produced by two species of Neotropical termites (subfamily Nasutermitinae) in a gallery forest (GF) of the Eastern Plains of Colombia. We sampled from the top of the BS to the edge at proportional distances, i.e. 20-100% for the largest BS in the soil surface and 50-100% for the smallest arboricole BS. Control soil was sampled 1 m apart from the BS. Values of total Corg were high in the BS produced by Nasutitermes sp1 (epigeic mound), while a high N mineralization process was observed in the same BS and in the Nasutitermes sp2 arboreal nest. The role of these two ecosystem engineers in nutrient cycling is discussed. 相似文献
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堤坝白蚁防治方法比较研究 总被引:3,自引:0,他引:3
我国堤坝白蚁防治,提出和使用过多种方法,该文对其中的5种方法加以比较,结果认为要彻底消灭堤坝白蚁,目前最有效的应是“三环节,八程序”的新技术。 相似文献
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Hizbullah Jamali Stephen J. LivesleyTracy Z. Dawes Garry D. CookLindsay B. Hutley Stefan K. Arndt 《Agricultural and Forest Meteorology》2011,151(11):1471-1479
Termites are estimated to contribute between <5 and 19% of the global methane (CH4) emissions. These estimates have large uncertainties because of the limited number of field-based studies and species studied, as well as issues of diurnal and seasonal variations. We measured CH4 fluxes from four common mound-building termite species (Microcerotermes nervosus, M. serratus, Tumulitermes pastinator and Amitermes darwini) diurnally and seasonally in tropical savannas in the Northern Territory, Australia. Our results showed that there were significant diel and seasonal variations of CH4 emissions from termite mounds and we observed large species specific differences. On a diurnal basis, CH4 fluxes were least at the coolest time of the day (∼07.00 h) and greatest at the warmest (∼15.00 h) for all species for both wet and dry seasons. We observed a strong and significant positive correlation between CH4 flux and mound temperature for all species. A mound excavation experiment demonstrated that the positive temperature effect on CH4 emissions was not related to termite movement in and out of a mound but probably a direct effect of temperature on methanogenesis in the termite gut. Fluxes in the wet season were 5-26-fold greater than those in the dry season. A multiple stepwise regression model including mound temperature and mound water content described 70-99% of the seasonal variations in CH4 fluxes for different species. CH4 fluxes from M. nervosus, which was the most abundant mound-building termite species at our sites, had significantly lower fluxes than the other three species measured. Our data demonstrate that CH4 flux estimates could result in large under- or over-estimation of CH4 emissions from termites if the diurnal, seasonal and species specific variations are not accounted for, especially when flux data are extrapolated to landscape scales. 相似文献
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Stephen J. Livesley Samantha GroverLindsay B. Hutley Hizbullah JamaliKlaus Butterbach-Bahl Benedikt FestJason Beringer Stefan K. Arndt 《Agricultural and Forest Meteorology》2011,151(11):1440-1452
Tropical savanna ecosystems are a major contributor to global CO2, CH4 and N2O greenhouse gas exchange. Savanna fire events represent large, discrete C emissions but the importance of ongoing soil-atmosphere gas exchange is less well understood. Seasonal rainfall and fire events are likely to impact upon savanna soil microbial processes involved in N2O and CH4 exchange. We measured soil CO2, CH4 and N2O fluxes in savanna woodland (Eucalyptus tetrodonta/Eucalyptus miniata trees above sorghum grass) at Howard Springs, Australia over a 16 month period from October 2007 to January 2009 using manual chambers and a field-based gas chromatograph connected to automated chambers. The effect of fire on soil gas exchange was investigated through two controlled burns and protected unburnt areas. Fire is a frequent natural and management action in these savanna (every 1-2 years). There was no seasonal change and no fire effect upon soil N2O exchange. Soil N2O fluxes were very low, generally between −1.0 and 1.0 μg N m−2 h−1, and often below the minimum detection limit. There was an increase in soil NH4+ in the months after the 2008 fire event, but no change in soil NO3−. There was considerable nitrification in the early wet season but minimal nitrification at all other times.Savanna soil was generally a net CH4 sink that equated to between −2.0 and −1.6 kg CH4 ha−1 y−1 with no clear seasonal pattern in response to changing soil moisture conditions. Irrigation in the dry season significantly reduced soil gas diffusion and as a consequence soil CH4 uptake. There were short periods of soil CH4 emission, up to 20 μg C m−2 h−1, likely to have been caused by termite activity in, or beneath, automated chambers. Soil CO2 fluxes showed a strong bimodal seasonal pattern, increasing fivefold from the dry into the wet season. Soil moisture showed a weak relationship with soil CH4 fluxes, but a much stronger relationship with soil CO2 fluxes, explaining up to 70% of the variation in unburnt treatments. Australian savanna soils are a small N2O source, and possibly even a sink. Annual soil CH4 flux measurements suggest that the 1.9 million km2 of Australian savanna soils may provide a C sink of between −7.7 and −9.4 Tg CO2-e per year. This sink estimate would offset potentially 10% of Australian transport related CO2-e emissions. This CH4 sink estimate does not include concurrent CH4 emissions from termite mounds or ephemeral wetlands in Australian savannas. 相似文献