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611.
Mingteh Chang Christopher M. Crowley Ahmad A. Nuruddin 《Resources, Conservation and Recycling》1995,13(3-4)
A greenhouse study was conducted to evaluate the response of herbaceous mimosa (Mimosa strigillosa) to six levels of cyclic soil moisture stresses in a 17-week period. The results showed that the cultivar continued to grow and the biomass continued to increase even when the soil moisture stress was as high as at the wilting point (1500 Kpa). Also, transpiration recovery rate was quick and values of root/shoot ratio were high when the plant was subject to the cyclic moisture stress condition. All these characteristics, along with strong rooting and spreading ability, suggest this legume as a promising drought hardiness species for reclamation purposes. 相似文献
612.
唐山地震后冀东地区不断发生的岩溶地质灾害,分别与震区地壳应力骤增、岩溶发育、覆盖层薄、地下水活动强及抽排蓄水措施不当有关。用加强管理和排截堵方法已减轻了灾害损失。 相似文献
613.
IntroductionDuringthepastseveraldecadesnumerousinvestigationsonproductivity,physiologyandecologyofplantssubjectedtotheincreas?.. 相似文献
614.
615.
The toxic effects of Cr(Vl) on antioxidant enzymes of Oxya chinensis(Orthoptera: Acridoidae) were determined. Changes in the activities of the antioxidant enzymes superoxide dismutase(SOD), catalase(CAT), and guaiacol peroxidase(GPx) were measured in O. chinensis insects injected with Cr(VI). Fifth-nymphs of O. chinensis insects were injected with Cr(VI) with different concentrations (0, 75, 150, 225, 300, 375, 450 mg/kg of body weight). The results showed that Cr(VI) led to the change of SOD, CAT, and GPx activities at different concentrations, which revealed that: (1) The oxidative stress of SOD increased with the increase of Cr (VI) concentration. (2) With the increase of Cr (VI) concentrations, CAT activities for females increased at lower concentrations, but decreased at higher concentration range, which indicated that antioxidant system of O. chinensis was not influenced by the presence of Cr (VI). A very similar response to Cr(VI) effect for males indicated that Cr(VI) concentrations were not high enough to damage O. chinensis in terms of CAT. (3) The GPx activity for females increased in all treatments, which revealed that the damage power of Cr(VI) was increased with the increase of Cr(Vi) concentrations in terms of GPx, but the effect was not so remarkable. There was not a consistent trend of GPx activities for males in all treatments of Cr(VI). Cr(VI)-induced changes in antioxidant enzymes were different for SOD, CAT and GPx, of which the tendency was that activities generally changed with increase of concentrations of Cr(VI) suggesting SOD, CAT, and GPx could serve as indices of oxidative stress to some extent. 相似文献
616.
某隧道进口段滑坡的发生是由于隧道开挖过程中破碎围岩向隧道开挖临空面位移,进而引发的坡面岩土体的失稳。数值模拟结果表明,因隧道开挖引起的洞顶区边坡岩体应力水平下降的区域一直延续到地表,这种应力场的变化会直接导致边坡表面的变形和破坏,表现在以隧道轴线为中心,向两侧呈扇形展开的坡体产生了一定的沉降变形。对比结果表明滑坡区与由隧道开挖引起的坡体附加位移较大的区域基本相当,说明此滑坡是由于隧道开挖引起了围岩应力场调整,导致围岩产生向洞内的位移变形,从而使岩体发生松动而引发的。 相似文献
617.
618.
从某大型储罐复合地基沉降机理分析入手,合理选择沉降计算公式,对建造在该类复合地基上的大型储罐沉降量作计算,并经实测沉降资料对比后,验证该类储罐沉降计算方法的适用性,为今后类同工程地质条件下,储罐基础的优化设计积累经验.图1,表1,参3. 相似文献
619.
Lihong WANG Xiaohua HUANG Qing ZHOU 《Frontiers of Environmental Science & Engineering in China》2008,2(3):364-369
Seed germination of plants with various acid-resistance display different responses to acid rain. To understand the reason
why such differences occur, the effects of simulated acid rain (pH 2.5–5.0) on the activities of peroxidase (POD) and catalase
(CAT) during seed germination of rice (O. sativa), wheat (T. aestivum), and rape (B. chinensis var. oleifera) were investigated. Results indicated that the maximum change in activities of CAT and POD by acid rain treatment with different
acidity and time in relation to the referent treatment without acid rain, was in the order: rice (28.8%, 31.7%) < wheat (34.7%,
48.3%) < rape (79.3%, 50.0%). The pH level for which the treatment with acid rain did not cause significant difference (p < 0.05) was in the order: rice (3.5).wheat (4.0).rape (5.0). Moreover, the change in activity of POD was higher than that
of CAT, which showed that POD was more sensitive to acid rain stress than CAT. The difference in the ability of POD and CAT
in removing free radicals was one reason why the germination indexes of these three species behaved differently.
__________
Translated from Environmental Science, 2005, 26(6): 123–125 [译自: 环境科学] 相似文献
620.
Joseph Alcamo Lilibeth Acosta-Michlik Alexander Carius Frank Eierdanz Richard Klein Dörthe Krömker Dennis Tänzler 《Regional Environmental Change》2008,8(4):137-149
In this study we develop an “inference modeling” approach to compare and analyze how different disciplines (economics, political
science, and behavioral science/environmental psychology) estimate vulnerability to drought. It is thought that a better understanding
of these differences can lead to a synthesis of insights from the different disciplines and eventually to more comprehensive
assessments of vulnerability. The new methodology consists of (1) developing inference models whose variables and assertions
incorporate qualitative knowledge about vulnerability, (2) converting qualitative model variables into quantitative indicators
by using fuzzy set theory, (3) collecting data on the values of the indicators from case study regions, (4) inputting the
regional data to the models and computing quantitative values for susceptibility. The methodology was applied to three case
study regions (in India, Portugal and Russia) having a range of socio-economic and water stress conditions. In some cases
the estimates of susceptibility were surprisingly similar, in others not, depending on the factors included in the disciplinary
models and their relative weights. A new approach was also taken to testing vulnerability parameters by comparing estimated
water stress against a data set of drought occurrences based on media analysis. The new methodologies developed in this paper
provide a consistent basis for comparing differences between disciplinary perspectives, and for identifying the importance
of the differences.
相似文献
Joseph AlcamoEmail: |