野茼蒿对镉的富集及其镉耐性

通过盆栽试验研究了不同镉（Cd）浓度（0、30、60、90、120、150、180mg.kg-1）胁迫下野茼蒿（Crassocephalum crepidioides（Benth.）S.Moore）的生长及其对Cd的富集特征。结果表明,随着Cd添加水平的增大,处理组野茼蒿的主根长、株高、叶绿素含量、根和地上部生物量均呈降低趋势,且主根长、株高、根和地上部生物量均显著低于对照植株;当Cd添加水平不断提高,处理组野茼蒿根和地上部Cd浓度呈显著增加趋势,而累积总量呈先增加后下降的趋势,但仍显著高于对照植株。处理Cd浓度为180mg.kg-1时,野茼蒿地上部Cd浓度最高,为1288.12mg.kg-1;处理Cd浓度为60mg.kg-1时,野茼蒿地上部Cd累积量最高,为每盆4.28mg。当Cd浓度≤90mg.kg-1时,野茼蒿生长正常,未出现Cd中毒症状。野茼蒿地上部Cd富集系数和转移系数分别为3.48～21.71和1.12～2.31。因此,野茼蒿对Cd具有较强的耐受性和转运能力以及其地上部对Cd的累积能力,适合于Cd污染土壤的植物修复。     

Ethnobotanical investigation and diversity of Gbolo (Crassocephalum rubens (Juss. ex Jacq.) S. Moore and Crassocephalum crepidioides (Benth.) S. Moore), a traditional leafy vegetable under domestication in Benin

Thirty five villages randomly selected across ethnic and agro-ecological zones of Benin were surveyed to document the indigenous knowledge associated with the domestication (bringing into cultivation), production and utilization of vegetable Gbolo (Crassocephalum spp.). The study revealed the existence of different morphotypes (1–4 per village) corresponding to two botanical species (Crassocephalum rubens (Juss. ex Jacq.) S. Moore) and (Crassocephalum crepidioides (Benth.) S. Moore) found unequally distributed throughout the country. The domestication (bringing into cultivation from the wild) of Gbolo was started in many villages and with some tribes in southern Benin, the vegetable is already being produced in sole cropping for commercial purposes. Regular consumption (49.90 % of responses) and scarcity (20.30 % of responses) were the two main reasons attributed by the interviewees for domestication of the vegetable. The cultural practices recorded were of five categories. The commonest cropping system found was mixed or inter-row cropping (92.31 % of producers) with either vegetable crops (53.85 % of producers) or non-vegetable crops (38.46 % of users). Sauce prepared with either fresh or dried leaves was the main type of preparation of Gbolo and the vegetable was reported to possess special nutritional and medicinal values. For further promotion, important researches directions are suggested.     

Cadmium and zinc accumulation in willow and poplar species grown on polluted soils

Woody plant species that produce high biomass have been proposed for use in phytoremediation technology. We investigated the accumulation of cadmium (Cd) and zinc (Zn) in Salix babylonica, S. caprea, S. dasyclados, S. matsudana × alba, S. purpurea, S. smithiana, Populus tremula, and P. nigra clones grown in a pot experiment on a Calcaric and a Eutric Cambisol (pH 7.2 and 6.4) of different levels of contamination (total metal concentrations in mg kg^–1 in soil A: 32.7 Cd, 1760 Zn; soil B: 4.34 Cd, 220 Zn). Generally, the tested clones tolerated large metal concentrations in soils and had larger Cd and Zn concentrations in leaves compared to the roots. The largest Cd concentrations in leaves were found in two clones of S. smithiana (440 mg kg^–1 on soil A; 70 mg kg^–1 on soil B). One of the S. smithiana clones had also the largest Zn concentrations (870 mg kg^–1) on soil B but accumulated slightly less Zn than a S. matsudana × alba clone (2430 mg kg^–1) on soil A. The Cd concentrations in leaves of both S. smithiana clones on soil A are the largest ever reported for soil‐grown willows. The bioconcentration factors of the best performing clone reached 15.9 for Cd and 3.93 for Zn on the less contaminated soil B. Also based on the metal contents in leaves, this clone was identified as the most promising for phytoextraction. The metal concentrations in leaves observed in the pot experiment do not reflect those found in a previous hydroponic study and the leaf‐to‐root ratios are clearly underestimated in hydroponic conditions. This demonstrates the need for testing candidates for phytoextraction crops on soils rather than in hydroponics. Our data also show that the phytoextraction potential should be tested on different soils to avoid misleading conclusions.     

镉在两种菊芋品种中的吸收与转移特性研究

Jerusalem artichoke(Helianthus tuberosus L.) not just can be used for bioethanol production but may be potentially used in phytoremediation for the removal of heavy metal pollutants.Two Jerusalem artichoke cultivars,N2 and N5,were subjected to six cadmium(Cd) concentrations(0,5,25,50,100 and 200 mg L1) to investigate Cd tolerance and accumulation.After 21 days of growth,the effects of Cd on growth,chlorophyll content,net photosynthetic rate,intercellular CO2 concentration and malondialdehyde content were evaluated.Most growth parameters were reduced under Cd stress.The two Jerusalem artichoke cultivars had relatively high Cd tolerance and accumulation capacity(> 100 mg kg1),with N5 being more tolerant and having higher Cd accumulation than N2.Roots accumulated more Cd than stems and leaves.The bioconcentration factors(far higher than 1) and translocation factors(lower than 1) decreased with an increase in Cd applied.The results suggested that Jerusalem artichoke could be grown at relatively high Cd loads,and N5 could be an excellent candidate for phytoremediation of Cd-contaminated soils.     

Using kale (Brassica oleracea var. acephala) as a phytoremediation plant species for lead (Pb) and cadmium (Cd) removal in saline soils

Ornamental kale (Brassica oleracea var. Acephala) is usually planted from early autumn until late winter. Since most of the plants used for phytoremediation cannot be grown during this time, kale can be a suitable option for phytoremediation and utilized during autumn and winter in urban landscape, especially in metropolitan areas where high levels of cadmium (Cd) and lead (Pb) pollutions exist. Kale growth in saline soil at different growth stages (germination and vegetative growth stages) was studied in this investigation. A factorial experiment based on completely randomized design (CRD) with four replications was used in this study. Treatments included three levels of sodium chloride (NaCl) (0, 30, and 60 mg/kg), four levels of Cd (0, 4, 8, and 16 mg/kg), and four levels of Pb (0, 1, 5, and 10 mg/kg). Results indicated that increase in Cd and Pb concentrations in the soil decreased fresh and dry weights of the plants. The results of the various growth stages revealed that under salinity stress, kale plants were able to absorb more Pb than Cd and effectively remediate Pb in polluted and saline lands. Cd accumulation in control treatment was 6.2% more than that in the saline treatments, whereas, Pb accumulation in the highest NaCl level, 60 mg/kg salinity treatment was 7.64% more than that of the control condition. Also, proline content of the plants was significantly increased under Cd and Pb stress. From the results of this study, it was concluded that using kale plant is recommended for phytoremediation of saline soils with 10 and 16 mg/kg Pb and Cd contents, respectively.     

Human-altered and human-transported (HAHT) soils in the U.S. soil classification system

ABSTRACT

Human-altered and human-transported (HAHT) soils are widespread across the globe and are concentrated near where people live and work. Although some of the HAHT soils are significant because they can be hazardous to human, animal, and plant health, most are not mapped or classified to the same extent as agricultural soils. The purpose of this article is to discuss the occurrence, types, and importance of HAHT soils and to document the historical and proposed classification of HAHT soils in Soil Taxonomy. There are two main forms of materials that define HAHT soils: human-altered soils formed in human-altered materials (HAM) from the soil surface to 50 cm (or to bedrock if shallower) or more and human-transported soils formed in human-transported materials (HTM) from the soil surface to 50 cm (or to bedrock if shallower) or more. The HAHT soils mainly occur in urban areas, transportation corridors, mined lands, landfills, filled shallow water, and agricultural areas on anthropogenic landforms. Hazards include danger from radioactivity, pollution, content of hazardous artifacts, or presence on unstable landforms that may fail during heavy rains or earthquakes. The HAHT soils are extensive, and their extent is growing. In the past, few HAHT soils were described or classified adequately because the U.S. Soil Taxonomy system was established for agricultural and other naturally occurring soils. However, HAHT soils are now being recognized and classified in many soil classification systems at very high levels. A new soil order is proposed for U.S. Soil Taxonomy that would include the most obvious profoundly and intentionally altered HAHT soils. A discussion and justification is given for an unofficial proposal. Input will be collected from international groups of scientists, and modifications of the unofficial proposal are expected. The long-term result of establishing a new soil order will be to enable proper classification, allocation, and mapping of HAHT soils worldwide.     

The relationship between Sr and Ca accumulation in the major constituents of a terrestrial community resident on a celestitic (Sr SO4) soil in S.W. England

The accumulation and depuration of Ca and Sr were measured in populations of the earthworm Lumbricus rubellus, originating from calcareous and acidic soils, following laboratory exposure to a Sr-rich soil and a control soil. Populations from acidic soils accumulated more Sr than those from calcareous soils, when placed in a Sr-rich soil. After transferal from a Sr-rich soil to Sr-free soil, all populations depurated the majority of their body Sr (84 %-96 %) whilst maintaining their body Ca concentration; the Sr excretion was greater in the populations originating from acidic soils. ICP-MS cation analysis demonstrated the majority of Ca and Sr to be located in anterior alimentary canal and the majority of Sr was lost from this region.     

Quantitative and Qualitative Traits of Natural Ecotypes of Perennial Grasses (Dactylis glomerata L., Festuca arundinacea Schreb., Phalaris tuberosa L., Brachypodium rupestre (Host) R. et S.) Collected in Southern Italy

In 1999, natural populations of Dactylis glomerata L., Festuca arundinacea Schreb., Phalaris tuberosa L. and the macrotherm species Brachypodium rupestre (Host) R. et S., were collected as seed in Southern Italy (Apulia, Basilicata and Campania regions) to evaluate the potential as forage of native germplasm under dry conditions, using available commercial cultivars as controls. The persistence of accessions, biometric, phenologic, productive and qualitative parameters of forage have been studied for a 3-year period (2000–2002) in a typical Mediterranean environment. D. glomerata is widely present in the studied area with two subspecies (subsp. glomerata L., subsp. hispanica (Roth) Nyman). The research pointed out significant differences in plant size, earliness and single plant dry matter (DM) production. All the natural ecotypes belonging to this species showed higher persistence than the control cultivars. Some natural ecotypes appeared to have potential for improving DM yield (subsp. glomerata ecotypes) and reducing neutral detergent fibre (NDF) content (subsp. hispanica ecotypes). Natural ecotypes belonging to F. arundinacea, P. tuberosa, and B. rupestre are sporadically present in the studied area. Among them, two ecotypes of P. tuberosa, showing higher winter growth and earliness compared to cv. ‘Holdfast’, seem to be interesting for a future breeding programme.