首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:从到   被引次数:从到   他引次数:从到 提示：输入*表示无穷大
全文获取类型
  收费全文   7篇
  免费   1篇
专业分类
林业   1篇
  3篇
综合类   1篇
植物保护   3篇
出版年
  2021年   2篇
  2017年   1篇
  2016年   1篇
  2014年   2篇
  2009年   2篇
排序方式： 共有8条查询结果，搜索用时 97 毫秒
1
1.
Journal of Soils and Sediments - Complex phenomena of the precipitation and accumulation of calcium carbonate in urban soils and sediments have been studied. They are linked to the interactions...  相似文献   
2.

Purpose

Metal distribution patterns among geochemical fractions are informative for metal phytoavailability. Compost added to polluted soils may adsorb metals on the less phytoavailable fractions. A bioassay experiment was conducted to establish possible correlations between metal concentrations in different soil fractions and metal contents in edible plant parts and to investigate the influence of different compost loads on heavy metal availability to plants.

Materials and methods

Chinese cabbage plants were grown in pots with sandy and clayey soils and soils mixed with different doses of biosolid compost spiked with soluble heavy metal salts (Cd, Cu, and Pb). The metals’ distribution pattern in the soil and mixed samples was determined by sequential extraction procedure (modified BCR protocol). The studied fractions, from most to least bioavailable, were water-extractable (WE), exchangeable-adsorbed (EXC), associated with carbonates and acetic acid-soluble forms (CARB), occluded by reducible (hydro)oxides of Fe and Mn (RO), and associated with organic matter (OM) and a residual fraction (RES). Metal concentrations in soil extracts and in the digested plant tissue were measured by ICP-AES.

Results and discussion

The highest compost doses (72 and 115 Mg ha?1) enhanced cabbage yield significantly. No excessive phytoaccumulation of metals was observed in plants grown in the clayey soil or its mixtures with compost. The compost dose of 72 Mg ha?1 was optimal in decreasing Cu accumulation by plants grown in sandy soil, and 28.8 Mg ha?1 was found to be effective in reducing Cd and Pb uptake. Metals were accumulated in plants primarily from the WE, EXC, and CARB fractions, whereas other fractions decreased phytoaccumulation. Compost addition suppressed heavy metal mobility, but different fractions were active in pollutant sorption, depending on soil type and metal.

Conclusions

Compost addition increased metal proportions in the RO and OM fractions, reducing metal phytoavailability. This is especially important for sandy soils with low adsorption ability and higher vulnerability to metal pollution than clayey soils. A compost dose of 20% v/v (or 28.8 Mg ha?1) effectively reduced plant accumulation of Cd and Pb. We propose using the first three steps of the modified BCR protocol as a three-step sequential-extraction procedure for the most phytoavailable fractions of heavy metal: WE, EXC, and CARB.  相似文献   
3.
Phytoparasitica - Moths of Coniesta ignefusalis (Hampson) were collected by automatic light traps on millet field near Bamako in 2018. The light trap data shows three periods of moth flight. The...  相似文献   
4.
1,2,3-噻二唑联-1,2,4-三唑衍生物的合成及抑菌活性   总被引：1，自引：0，他引：1  
以4-氨基-3-(4-甲基-1,2,3-噻二唑)-1,2,4-三唑-5-硫酮为原料,与醛在冰乙酸中回流制得15个新型4-取代亚氨基-3-(4-甲基-1,2,3-噻二唑)-1,2,4-三唑-5-硫酮化合物,其结构经IR、1H NMR 及元素分析表征,其中,化合物 5c 的结构经单晶测试确证,该晶体属单斜晶系,P2(1)/c空间群,晶胞参数a=1.403 7(3) nm,b=1.570 5(3) nm,c=0.686 4(14) nm,β=102.06(3)°,V = 1.479 8(5) nm3,Z=4,F(000)=656。初步的抑菌活性测试结果表明;所有化合物对黄瓜灰霉病菌Botrytis cinerea都有较好的抑制作用,化合物 5l 的抑制率达87%, 5c、5d和5f 的抑制率在78%左右; 5a 对小麦赤霉病菌Gibberella zeae的抑制率为78.7%; 5m 对西瓜炭疽病菌Colletotrichum lagenarium的抑制率为65.6%。  相似文献   
5.
A novel method is proposed for correcting metal fraction concentrations remaining within the sediment containing the solid residue of the sequentially extracted fraction. An easy‐to‐use Excel spreadsheet was prepared to assist adjustment of concentration in each fraction and demonstrate the difference between adjusted and non‐adjusted metal concentration of the fraction. The demonstration of a calculation of the modified BCR protocol data showed that this difference may reach 10–15% of the result value. The spreadsheet is available to download at: http://departments.agri.huji.ac.il/zabam/Rosen_Chen_Fraction_Adjustment_Formulae.xls  相似文献   
6.
Leaves of durum wheat infested with mines of the cereal leaf miner Syringopais temperatella Lederer (Lepidoptera: Scythridae) were collected from fields in Israel in spring 2016 and 2017. The parasitoids and moths reared from the leaf mines in the lab were identified and counted according to sex. The sex ratios of S. temperatella were 1:0.73 (♀ :♂) in 2016 and 1:0.41 in 2017. A cross-correlation analysis revealed that males appeared three days ahead of females (p<0.05). The following parasitoids were reared: Eulophidae (Cirrospilus vittatus Walker, Diglyphus chabrias (Walker), D. isaea (Walker), D. sensilis Yefremova, D. pusztensis (Erd?s & Novicky), Necremnus tidius (Walker), Neochrysocharis formosus (Westwood), Pnigalio gyamiensis Myartseva & Kurashev, P. pectinicornis Linnaeus), Pteromalidae (Norbanus sp.) and Braconidae (Habrobracon stabilis (Wesmail), Apanteles sp.); and Icheumonidae (Campoplex sp.). In all cases, the parasitoids emerged substantially prior to the mass appearance of the moths. The hatching dynamics of ecto- and endoparasitoids were also asynchronous. Most species of ectoparasitoids hatched three days ahead of the endoparasitoids (p<0.05). Syringopais temperatella recorded on clover revealed a similar dynamics of male appearance ahead of female, with a of female-to-male ratio of 1:0.25, and fewer parasitoid species.  相似文献   
7.
  • ? We studied mortality rates of birch, small-leaved linden, pedunculate oak, Norway maple, black alder, common ash and Norway spruce, assessed through two inventories of 12 664 trees in the unmanaged mixed deciduous forests of Oranienbaum Park, northwestern Russia, in 1981 and 2003.
  • ? Our objectives were to evaluate if (a) long-term mortality rates vary among species, and if (b) crown condition, age and tree size affect the probability of mortality.
  • ? Over this period, tree mortality rates in the park varied annually from 1 to 3% for healthy and moderately healthy trees, and from 3.9 to 9.3% for declining trees. The lowest mortality rates were observed for small-leaved linden and oak (0.8 and 1.0%, respectively), and the highest rate for birch (2.7%). We found (1) a significant and consistent association between tree condition and the probability of mortality, and (2) significantly higher mortality rates in smaller trees of ash, maple and oak.
  • ? The effect of species-specific biology on mortality rates in the Oranienbaum Park was largely overridden by the “health status” and environmental conditions of the trees (e.g. degree of crown shading). The observed rates were similar to the estimates from natural temperate deciduous forests in both Europe and North America, indicating similar intensity of mortality in these ecosystems under natural conditions.
    •   相似文献   
    8.
    Spatial and structural characteristics of plant communities in the steppe ecosystems of the Baikal region, Russian Federation have been researched in connection with climate change and grazing. The present study, based on a total of 15 typical steppe sampling plots, investigated above-ground biomass （AGB）, below-ground biomass （BGB）, total biomass （TB） and root：shoot ratios （R：S） and their relationships with climatic factors and grazing. All biomass components varied widely depending on the climatic parameters and the degree of grazing affected transformation. A strong negative correlation between mean annual temperature （MAT） and total plant biomass was revealed for all study area. Mean annual precipitation （MAP） signiifcantly affected communities productivity increasing only in the south of the region. Due to the large and mountainous territory, the inlfuence of latitude and elevation （mountain） factors on the components of the biomass were studied. Although all studied plant steppe communities were transformed by uncontrolled grazing, their productivity is signiifcantly reduced only at plots with maximum digression. Vegetation shift is an indicator of climate change, as well as providing a diagnostic tool to build predictive models. Based on the complex index of effective precipitation, it was revealed that at the end of last century in the steppes of the Baikal region the structural and production processes will be affected by an arid climate trend.  相似文献   
    1
    设为首页 | 免责声明 | 关于勤云 | 加入收藏

    Copyright©北京勤云科技发展有限公司  京ICP备09084417号