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21.
Physiological Age of Host Plant Foliage and Survival of Gypsy Moth Larvae   总被引:1,自引:0,他引:1  
The pH of leaf homogenates of common birch (Betula verrucosa L.), a food plant of gypsy moth (Lymantria dispar L.) larvae, was measured at different times of day in the course of leaf organogenesis, and midgut pH was measured in gypsy moth larvae phenotypically differing in the color of the hypodermis at the fifth instar. A possible relation between these parameters is discussed.  相似文献   
22.
plane decaying leaves have been found capable of removing chromium and nickel ions from aqueous solutions. The removal efficiency depends upon the pH conditions, ions components and concentrations, and concentrations of leaves in media. The maximum removal for unique Cr6+ is about 7.5-8.0g/kg leaves at pH 4. 0, for unique Ni2+ about 2. 6g/kg at the region of PH5. 0-5.5. Under the described conditions nickel increases chromium uptake by plane decaying leaves from solution.  相似文献   
23.
Up to now only very few studies in biomonitoring of organic air pollutants have been published taking into account the strong influence mean temperatures have on the accumulation process into plants during the course of the exposition. Temperature governed sorption as well as the plants vitality pose a major source of uncertainty making inter-study comparisons difficult. Different surface-to-volume ratios of plant foliage lead to strongly varying concentration effects in different plant species. Moreover a plants content of waxes and lipids must be considered in order to relate xenobiotic concentrations to the compounds being most efficient in the bioaccumulation process. Some of these factors are evaluated in regard to the use of plants as biomonitors for organic air pollutants. Another aim is to deduce the mean ambient gas phase concentrations from PAH concentrations determined in the biomonitor plants using vegetation-air partitioning coefficients which have been corrected for temperature dependent sorption as well as the plants lipid content. Restrictions of such approaches and methods of biomonitoring in general are discussed.  相似文献   
24.
封闭式芦苇湿地处理钻井泥浆的可行性研究   总被引:8,自引:0,他引:8       下载免费PDF全文
研究了现场中试条件下芦苇湿地处理钻井泥浆的可行性及钻井泥浆对土壤和芦苇等湿地介质的影响。研究结果表明:在7个月运行期内,单位面积钻井泥浆施入量5kg/m^2,20kg/m^2和40kg/m^2的芦苇湿地对矿物油的迁移降解率分别为75%-85%,78%-90%和65%-90%;钻进泥浆中的矿物油对湿地土壤的污染基本局限于表层,对深层土壤的污染趋势并不明显,一般40cm以下矿物含量已低于对照区表层土的背景值;钻井泥浆能增加芦苇的生物量,对芦苇品质指标的影响很小。  相似文献   
25.
造纸黑液的超声/絮凝联合处理研究   总被引:6,自引:0,他引:6  
以苇浆黑液为处理样品 ,利用超声与PFS/H2 O2 的协同预处理研究 ,结果表明 :它们的联合处理比单独用PFS/H2 O2 处理 ,CODcr的去除率提高 1 1 .39%~ 1 3 .31 % ;与同等条件处理结果相比 ,利用超声可节约PFS1 4 % ,H2 O2 50 %~ 80 % ;同时也表明 ,处理效果与探头的辐射面积关系不大 ,即使增加电功率 ,效果也不明显 ,由此可推断这与黑液成份复杂有关。  相似文献   
26.
Combined effect of US/PFS on the black liquor of making paper   总被引:1,自引:0,他引:1  
The reed pulping black liquor is used as a sample. Researches of (1) combined effect of ultrasound(US)/polyferric sulphate(PFS)/hydrogen peroxide(H2O2); (2) effects of the horn tip areas; (3) effect of dose of PFS were carried. Extrapolation of these experiments indicated treatment results are possibly related to complex chemical compositions in the reed pulping black liquor.  相似文献   
27.
Vertical and temporal distributions of N and P in soil solution in aquatic-terrestrial ecotone (ATE) of Taihu Lake were investigated, and the relations among N, P, ORP (oxidation reduction potential), TOC, root system biomass and microorganism were studied. As a whole, significant declines in TN, NO3^--N, DON (dissolved organic nitrogen) and TP concentration in soil solution have occurred with increase of the depth, and reached their minima at 60 cm depth, except for NH4^+-N, which increased with depth. The concentration of TP increased gradually from spring to winter in the topsoil, the maximum 0.08 mg/L presented in the winter while the minimum 0.03 mg/L in spring. In the deeper layer, the concentration value of TP fluctuated little. As for the NO3^--N, its seasonal variation was significant at 20 cm depth, its concentration increased gradually from spring to autumn, and decreased markedly in winter. Vertical and temporal distribution of DON is contrary to that of NO3^--N. The results also show that the variation of N and P in the percolate between adjacent layers is obviously different. The vertical variation ofTN, TP, NO3^--N, NH4^+-N and DON is significant, of which the variation coefficient of NO3^--N along the depth reaches 100.23%, the highest; while the variation coefficient of DON is 41.14%, the smallest. The results of correlation analysis show that the concentration of nitrogen and phosphorus correlate significantly with TOC, ORP, root biomass and counts of nitrifying bacteria. Most nutrients altered much from 20 to 40 cm along the depth. However, DON changed more between 60 and 80 cm. Results show that soil of 0-60 cm depth is active rhizoplane, with strong capability to remove the nitrogen and phosphorus in ATE. It may suggest that there exists the optimum ecological efficiency in the depth of above 60 cm in reed wetland. This will be very significant for ecological restoration and reestablishment.  相似文献   
28.
环境因素对芦苇湿地CH4排放的影响   总被引:17,自引:0,他引:17  
用封闭式箱法对辽河三角洲芦苇湿地温室气体CH4 排放进行了长期观测 .结果表明 ,CH4 排放有明显的季节变化规律 ,平均通量为 52 0 μg·m- 2 ·h- 1.土壤产CH4 活性主要发生在 0~ 5cm土层中 ,并随土层深度的增加而显著下降 .CH4 排放受环境因素影响很大 ,土壤氧化还原电位在 -1 1 0mV时就有CH4 排放 ,其排放量随氧化还原电位的下降而增加 .另外 ,随着淹水深度的增加 ,CH4 排放反而减少 .在测定期内 ,CH4 排放与温度呈明显的正相关 (R2 =0 1 96,n =2 1 ,P <0 .0 5) .  相似文献   
29.
垂直流芦苇人工湿地对化粪池出水净化效果的研究   总被引:2,自引:0,他引:2  
通过在同种基质上种植相同数目的芦苇,研究了垂直流人工湿地对化粪池出水的净化效果,以及不同水力停留时间对污水净化效果的影响。结果表明,同种填料、不同水力停留时间,对污水中TP、NH4^+-N.CODcr的净化效果不同。由于芦苇根系和微生物的吸收与分解作用,以及基质的吸附作用,种植芦苇的人工湿地出水水质要比未种芦苇的好。  相似文献   
30.
Quercus ilex L. leaves were collected four times in one year at six urban sites and one remote area in order to determine trace element and PAH accumulation through concomitant analyses of unwashed and water-washed leaves. Both unwashed and washed leaves showed the highest amounts of trace elements and PAHs in the urban area. Unwashed leaves showed greater differences between urban and remote areas and among the urban sites than washed leaves for trace element and PAH concentrations. Water-washing resulted in a significant (P<0.001) decrease in leaf concentrations of Cr, Cu, Fe, Pb, V and Zn. By contrast, Cd and total PAH concentrations showed no differences between unwashed and washed leaves.  相似文献   
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