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371.
不同木豆品种耐铝性的基因型差异及其机理研究 总被引:1,自引:0,他引:1
以6个品种的木豆为材料,探讨了木豆品种间耐铝性的基因型差异及其机制。铝对根伸长的抑制大小及苏木精对根尖的染色模式的研究结果表明,不同品种木豆的耐铝性基因型差异明显。在铝胁迫条件下,去除根尖吸附的粘胶,耐铝的基因型MD2和敏感的基因型MD5根的伸长率均减少,而根尖被苏木精染色程度加深;去除粘胶对MD2的影响大于MD5,说明粘胶对根尖的保护是木豆抵御铝毒的一个重要机制。虽然铝胁迫可诱导木豆根系分泌柠檬酸和苹果酸,但根系苹果酸的分泌量在MD2和MD间无显著差异,MD2柠檬酸的分泌量甚至低于MD5。 相似文献
372.
ABSTRACT: A rainfall simulator was used on runoff plots to study the effects of simulated canopy cover, trampling disturbance, and soil type on nil and interrill erosion. Sandy loam soil was more erodible than clay loam soil. Furthermore, the simulated canopy cover signffi-Soilfactorsrelatedtonil cantly influenced nil and interrill erosion. The effect of trampling on rill and interrill erosion varied with soil type (clay loam versus sandy loam) and erosion type (nh versus interrill erosion). On large plots, where both nil and internill erosion were involved, 30 percent trampling significantly increased soil loss. However, on small plots, 30 percent trampling significantly reduced interrill erosion. 相似文献
373.
Manouchehr Dadkhah Gerald F. Gifford 《Journal of the American Water Resources Association》1980,16(6):979-986
ABSTRACT: This study evaluated the impact of selected soil surface characteristics on infiltration rates and sediment production from interrill erosion from loam soil. Treatments were two different grass species (crested wheatgrass and intermediate wheatgrass), three levels of grass cover (30, 50, and 80 percent), four levels of rock cover (5, 10, 15, and 20 percent), and six levels of simulated trampling (10 to 60 percent of the respective plot area by 10 percent increments). Results indicated that plots with sod forming grass infiltrated only slightly more water than plots with bunchgrass, though the differences were significant. Trampling reduced infiltration rates significantly. On uncompacted soil, infiltration rates increased as percentage of rock cover increased. Trampling gradually destroyed this relationship however. Rock cover did not significantly affect sediment production. The tradeoff between vegetal cover and rock cover was affected by simulated trampling. Once trampling disturbance reached 20 percent, no relationship between vegetal cover and rock cover existed. Trampling was the most important factor influencing infiltration rates, explaining 35 to 48 percent of the variation in infiltration rates. The most important factor influencing sediment production was grass cover, which explained 40 to 62 percent of the variations associated with sediment yield at various trampling percentages. Results strongly suggest that, for slopes and soils as used here, adequate watershed protection may be obtained by maintaining 50 percent protective ground cover. Additional validation studies are recommended. 相似文献
374.
Sun WH Lo JB Robert FM Ray C Tang CS 《Environmental science and pollution research international》2004,11(4):260-266
GOAL, SCOPE AND BACKGROUND: This glasshouse study is aimed at evaluating tropical plants for phytoremediation of petroleum hydrocarbon-contaminated saline sandy subsurface soils. Tropical plants were selected for their ability to tolerate high salinity and remove No. 2 diesel fuel in coastal topsoil prior to further investigation of the phytoremediation feasibility in deep contaminated soils. The residual petroleum-hydrocarbon contaminant at the John Rogers Tank Farm site, a former petroleum storage facility, at Hickam Air Force Base, Honolulu, Hawaii, is located in a coastal area. It lies below a layer of silt in the subsurface, in loamy sand characterized by moderate salinity and high pH. Little is known regarding the ability of tropical plants to remediate petroleum hydrocarbon-contaminated subsurface soil in Hawaiian and other Pacific Island ecosystems although suitable plants have been identified and utilized for bioremediation in surface soil or marine sediments. METHODS: The experiments were conducted in long narrow pots under glasshouse conditions in two phases. A preliminary experiment was done with nine tropical plants: kiawe (Prosopis pallida), milo (Thespesia populnea), common ironwood (Casuarina equisetifolia), kou (Cordia subcordata), tropical coral tree (Erythrina variegata), false sandalwood (Myoporum sandwicense), beach naupaka (Scaevola sericea), oleander (Nerium oleander), and buffelgrass (Cenchrus ciliaris). These plants were screened for resistance to high salinity treatment (2% NaCl) and two diesel fuel levels (5 and 10 g No. 2 diesel fuel/kg soil) in separate treatments. Plants that showed good tolerance of both factors were further evaluated in a second phase for their efficacy in the phytoremediation of diesel-fuel petroleum hydrocarbons under moderate salinity treatment (1% NaCl). RESULTS: Tropical coral tree and buffelgrass were susceptible to either 2% NaCl or diesel fuel at 10 g/kg soil, but tolerant of diesel fuel at 5 g/kg soil. Kiawe, milo, kou, common ironwood, N. oleander, beach naupaka and false sandalwood were tolerant of high salinity (2% NaCl) or high diesel fuel level (10 g/kg soil). These seven plants were also tolerant of the combined adverse effects of a moderate salinity (1% NaCl) and 10 g diesel fuel/kg soil. Three trees, kiawe, milo and kou significantly accelerated the degradation of petroleum hydrocarbons in the soil spiked with 10 g diesel fuel/kg soil under a moderate salinity treatment (1% NaCl). CONCLUSION: Thus the tropical woody plants, kiawe, milo and kou showed potential for use in phytoremediation of petroleum hydrocarbons in coastal tropical soils. RECOMMENDATIONS AND OUTLOOK: Two fast growing trees, milo and kou, appeared promising for further phytoremediation evaluation in experiments that simulate the soil profile at the field site. 相似文献
375.
Abstact While male mammals seek to maximize access to potential mates, females maximize feeding efficiency. Ranging patterns are therefore often sex specific. Sex-specific ranging patterns have also been reported for East African chimpanzees and a recent study on female ranging patterns concludes that social organization is best described by a male-bonded community model, where females occupy individual home ranges that are distributed within the boundaries of the male-defended range. In West African chimpanzees, however, such sex-specific ranging patterns have not been consistently observed and a bisexually bonded community model, where both sexes use the entire home range equally, has been suggested to best describe social organization. In this study we analyze 5 years of data on individual ranging patterns of chimpanzees in the Taï National Park (Côte dIvoire) to test specific predictions of the different models of chimpanzee social organization. We found that although males in Taï had slightly larger home ranges than females, all individual home ranges and core areas overlapped highly. Small individual home range size differences were entirely due to the use of peripheral areas and were correlated with female social dominance. These findings strongly support the bisexually bonded community model for Taï chimpanzees. Thus, we conclude that there are fundamental differences in the space-use patterns of East and West African chimpanzees and discuss possible factors leading to such differences.Communicated by D. Watts 相似文献
376.
首次报道了鞭式节丛孢的氯化钠和氯化镉耐受性,在查氏平板上培养39d,鞭式节丛孢对氯化钠的最高耐受浓度为0.6mol L^-1,对氯化镉的最高耐受浓度为3.0mmol L^-1;在LCMA平板上,0.18mol L^-1氯化钠抑制三维菌网的形成,0.30mol L^-1氯化钠抑制厚垣孢子的萌发,0.05mmol L^-1氯化镉抑制三维菌网形成,0.07mmol L^-1氯化镉抑制厚垣孢子萌发.图1表3参8 相似文献
377.
Kate L. Palphramand Geraldine Newton-Cross Piran C. L. White 《Behavioral ecology and sociobiology》2007,61(3):401-413
Badgers are carnivores that show considerable variation in their social and spatial organization. At the westernmost part of their range, in Britain and Ireland, variation in spatial organization appears to be determined by the availability of resources. However, the majority of studies has focussed at one end of the social/spatial spectrum, where population densities are high and adjacent territories are contiguous and non-overlapping. To examine whether the same limiting factors appear to apply across a wider range of badger densities, we established a study site in a predominantly coniferous habitat within an upland area of northeast England, where population densities were predicted to be low. Seasonal home ranges of individual badgers were largest in autumn, followed by summer and spring, then winter. This pattern is reflective of the likely seasonal changes in food availability within the area, as opposed to being related to breeding patterns. There were also significant correlations between territory size and the number of grassland patches (positive) and the proportion of grassland (negative), which are consistent with predictions from the Resource Dispersion Hypothesis. Although badgers at the site were living at low to moderate densities relative to many other studied populations in Britain, they showed patterns of spatial organization that were close to those of high-density populations. The nature of the relationship between resource availability and abundance patterns is likely to have important consequences for the conservation and management of badgers and other species that show flexible spatial organization. 相似文献
378.
379.
采用离子交换法制备了Na-、K-、Co-、NiZSM-5分子筛催化剂.测试了它们催化氧化NO的性能并通过XRD、BET、ICP-MS和Py-IR等表征,结果表明,CoZSM-5分子筛对NO催化氧化具有最高的活性,氧化率达到47%,主要是引入Co离子的ZSM-5表面酸性最适宜NO氧化.同时,在湿度100%条件下,考察了氧气浓度(5%~20%),空速与二氧化硫浓度(0~200×10-6)等对CoZSM-5分子筛催化氧化NO性能的影响.实验结果表明,在30℃、空速14400h-1和相对湿度100%条件下,SO2浓度在200×10-6以下对催化氧化NO基本无影响.56h催化剂稳定性实验结果表明,在30℃、NO进口浓度600×10-6、空速18000h-1和饱和水汽(RH:100%)条件下,CoZSM-5分子筛催化剂对NO的氧化率可维持在40%左右.因此CoZSM-5分子筛催化剂具有良好的NO氧化稳定性、抗水性和一定的抗硫性. 相似文献
380.
Donald Bruce 《Journal of Agricultural and Environmental Ethics》2003,16(6):595-604
This paper examines the ethical andsocial questions that underlie the present UKdiscussion whether GM crops and organicagriculture can co-exist within a given regionor are mutually exclusive. A EuropeanCommission report predicted practicaldifficulties in achieving sufficientseparation distances to guarantee lowerthreshold levels proposed for GM material inorganic produce. Evidence of gene flow betweensome crops and their wild relatives has beena key issue in the recent Government consultation toconsult on whether or not to authorizecommercial planting of GM crops, following theresults of the current UK farm scale trials.The admixture of imported Bt transgenes intolandrace varieties of Mexican maize alsopresents difficulties. An ethical evaluationis made of the claim that organic growersshould expect protection from adventitioustraces of GM constructs in their products. Towhat extent – on either side of the debate –can any particular group in society set upagricultural standards for itself that mayeffectively restrain others from an otherwisejust business? The assumptions behind notionslike ``purity'' and ``contamination'' areexamined, together with their underlying viewsof nature and human intervention. The 2001UK Agriculture and Environmental BiotechnologyCommission report is relevant to theseissues. While the Government wishes to promotethe UK biotechnology industry and is underpressure from US claims of trade restraint, astrong organic lobby demands purity from GMcontamination. Does this adversarial framingof the issues reflect broader public opinionin the UK public consultation? Inarriving at policy decisions, the role of thevirtue of tolerance is considered inpost-modern and Christian ethical contexts. 相似文献