Phytoremediation is a relatively new approach in remediating ecosystems contaminated by ecotoxic pollutants such as herbicides or heavy metals and especially cadmium （Cd）. Certain indicators of phytoremediation, as ...Phytoremediation is a relatively new approach in remediating ecosystems contaminated by ecotoxic pollutants such as herbicides or heavy metals and especially cadmium （Cd）. Certain indicators of phytoremediation, as plant growth, tolerance to Cd, and uptake, transfer factor （TF） and percent removal of Cd, were studied for 11 crops and 8 weed species in soil with varying levels of Cd （0-240 mg Cd kg＂ soil） under controlled environment. Cadmium accumulated mainly in roots （51%-86%, depending on the species）, while a 14%-49% was transferred to shoots （except for four species） the concentration being positively related to Cd level in soil. Highest concentration in the above ground plant part was measured in sugarbeets （41-101 mg Cd kg-1 DW） followed by Bromus sterilis （75）, Eruca sativa （32-82）, Cichorium intibus （35-80）, and maize （60 mg Cd kgl）. Based on the results it is concluded that sugarbeets, maize, C. intibus, B. sterilis, E. sativa, Apium graveolens, and Vicia sativa seem to have a potential in remediating Cd contaminated soils.展开更多
Phosphate was found to have neither influence on Cd transformation nor effect on plant Cd uptake in three Cd-amended upland soils.However,on submerged red earth,high phosphate dressing inhibited the transformation of ...Phosphate was found to have neither influence on Cd transformation nor effect on plant Cd uptake in three Cd-amended upland soils.However,on submerged red earth,high phosphate dressing inhibited the transformation of Cd from exchangeable fraction to other lower-available ones.Cadmium uptake by rice plants increased simultaneously with increasing phosphate supply though plant resistance to Cd also increased at high phosphate level.Application of phosphate as an amendment for Cd-contaminated soil was therefore not recommended in view of the increasing influx of Cd into food chain especially on flooded soils.展开更多
Napier grass （Pennisetum purpureum Schumach）, a C4 tropical plant, has high dry matter productivity and sustainability without the need for renovating every year due to good overwintering ability and the absence of ...Napier grass （Pennisetum purpureum Schumach）, a C4 tropical plant, has high dry matter productivity and sustainability without the need for renovating every year due to good overwintering ability and the absence of serious pathogens or insects injury. This grass is suitable for multipurpose use, providing forage, bioethanol feedstock and phytoremediation of cadmium （Cd） contaminated soil in Kyushu, Japan. When two cultivars of Napier grass （Wruk wona, WK and Merkeron, ME） were grown in Cd-contaminated soils, dry matter yield and the concentration and uptake of herbage Cd were higher in WK than in ME, and soil Cd concentration was reduced by 14% in a single season of cultivation. A dwarf variety of late-heading type （DL）, Napier grass had superior sustainability for more than 5 years in Miyazaki, Japan, and has gradually increased in cultivation areas for both cut-and-carry and grazing herbage production in cooperation with regional communities. Through the extension in several Kyushu areas, DL Napier grass required temperatures above -6.2 ~C for sustainability in winter, based on its threshold response to the lethal minimum temperature. DL Napier grass pasture can be utilized by grazing beef cattle even in early spring with temperate Italian ryegrass inter-sown into its inter-row spaces. Organic digested animal manure or sun-dried leguminous leaves as green manure can replace chemical fertilizers to reduce energy consumption and allow comparable productivity.展开更多
文摘Phytoremediation is a relatively new approach in remediating ecosystems contaminated by ecotoxic pollutants such as herbicides or heavy metals and especially cadmium （Cd）. Certain indicators of phytoremediation, as plant growth, tolerance to Cd, and uptake, transfer factor （TF） and percent removal of Cd, were studied for 11 crops and 8 weed species in soil with varying levels of Cd （0-240 mg Cd kg＂ soil） under controlled environment. Cadmium accumulated mainly in roots （51%-86%, depending on the species）, while a 14%-49% was transferred to shoots （except for four species） the concentration being positively related to Cd level in soil. Highest concentration in the above ground plant part was measured in sugarbeets （41-101 mg Cd kg-1 DW） followed by Bromus sterilis （75）, Eruca sativa （32-82）, Cichorium intibus （35-80）, and maize （60 mg Cd kgl）. Based on the results it is concluded that sugarbeets, maize, C. intibus, B. sterilis, E. sativa, Apium graveolens, and Vicia sativa seem to have a potential in remediating Cd contaminated soils.
文摘Phosphate was found to have neither influence on Cd transformation nor effect on plant Cd uptake in three Cd-amended upland soils.However,on submerged red earth,high phosphate dressing inhibited the transformation of Cd from exchangeable fraction to other lower-available ones.Cadmium uptake by rice plants increased simultaneously with increasing phosphate supply though plant resistance to Cd also increased at high phosphate level.Application of phosphate as an amendment for Cd-contaminated soil was therefore not recommended in view of the increasing influx of Cd into food chain especially on flooded soils.
文摘Napier grass （Pennisetum purpureum Schumach）, a C4 tropical plant, has high dry matter productivity and sustainability without the need for renovating every year due to good overwintering ability and the absence of serious pathogens or insects injury. This grass is suitable for multipurpose use, providing forage, bioethanol feedstock and phytoremediation of cadmium （Cd） contaminated soil in Kyushu, Japan. When two cultivars of Napier grass （Wruk wona, WK and Merkeron, ME） were grown in Cd-contaminated soils, dry matter yield and the concentration and uptake of herbage Cd were higher in WK than in ME, and soil Cd concentration was reduced by 14% in a single season of cultivation. A dwarf variety of late-heading type （DL）, Napier grass had superior sustainability for more than 5 years in Miyazaki, Japan, and has gradually increased in cultivation areas for both cut-and-carry and grazing herbage production in cooperation with regional communities. Through the extension in several Kyushu areas, DL Napier grass required temperatures above -6.2 ~C for sustainability in winter, based on its threshold response to the lethal minimum temperature. DL Napier grass pasture can be utilized by grazing beef cattle even in early spring with temperate Italian ryegrass inter-sown into its inter-row spaces. Organic digested animal manure or sun-dried leguminous leaves as green manure can replace chemical fertilizers to reduce energy consumption and allow comparable productivity.
