Cadmium(Cd)uptake by rice plants and its subsequent movement through food chains pose a notable risk to the health of both plants and humans.Therefore,understanding the fundamental mechanisms underlying the uptake and...Cadmium(Cd)uptake by rice plants and its subsequent movement through food chains pose a notable risk to the health of both plants and humans.Therefore,understanding the fundamental mechanisms underlying the uptake and movement process is essential.Through transcriptome analysis,we found that numerous abscisic acid(ABA)-related genes responded to Cd stress.Exogenous application of ABA significantly reduced Cd accumulation in the shoots and roots of rice plants.The increased ascorbate peroxidase(APX)enzyme activity,decreased H2O2 content,and elevated Cd tolerance index collectively suggest that ABA may mitigate the toxicity of Cd in rice plants.Further study revealed that exogenous ABA reduced Cd accumulation by regulating Cd transport and cell wall sequestration.Consistently,mutation of the ABA signaling factor OsABI5 resulted in a significant increase in Cd accumulation in shoots.Moreover,foliar spraying of ABA during the grain-filling stage significantly reduced Cd accumulation in rice grains,which was attributed mainly to decreased Cd uptake and the inhibition of Cd transportation from roots to shoots and from leaves to grains.These findings elucidate the underlying mechanisms of the ABA-mediated response to Cd stress in rice and provide a practical reference for coping with Cd pollution in farmlands.展开更多
The addition of silicon(Si)and organic fertilizers to soil conditioners can inhibit the transfer of heavy metal ions from soil to crops.However,it is not clear how Si and organic fertilizers affect soil properties and...The addition of silicon(Si)and organic fertilizers to soil conditioners can inhibit the transfer of heavy metal ions from soil to crops.However,it is not clear how Si and organic fertilizers affect soil properties and the micro-ecological environment and thereby reduce cadmium(Cd)accumulation in rice.In this study,the effects of L-type soil conditioners containing Si and organic fertilizers on bacterial and fungal community diversity,soil pH,organic matter,and available Si were analyzed with field experiments at two sites in Liuzhou City and Hezhou City,respectively,in Guangxi,China.With the increase of Si and organic fertilizer content in soil conditioner,rice yield respectively increased by 16.8–25.8 and 6.8–13.1%,and rice Cd content decreased significantly by 8.2–21.1 and 10.8–40.6%,respectively,at the two experimental sites.Soil microbiome analysis showed that the increase in abundance of Firmicutes and Actinobacteriota bacteria associated with Cd adsorption and sequestration,and Basidiomycota fungal populations associated with degradation of macromolecules favored the inhibition of soil Cd activity(soil exchangeable Cd decreased by 14.4–14.8 and 18.1–20.6%).This was associated with an increase in organic matter and Si content caused by applying soil conditioners.In conclusion,L-type soil conditioners,rich in Si and organic fertilizer,can reduce soil Cd bioavailability by regulating the dominant Cd passivating flora in the soil and ultimately reduce Cd accumulation in rice.展开更多
Brassica napus,one of the most important oil crops cultivated globally,is severely impacted by prolonged soil contamination with cadmium(Cd),resulting in decreased yields and poor seed quality.This crop exhibits a hig...Brassica napus,one of the most important oil crops cultivated globally,is severely impacted by prolonged soil contamination with cadmium(Cd),resulting in decreased yields and poor seed quality.This crop exhibits a high adsorption capacity for Cd,making creating seed resources with low Cd accumulation an essential strategy to alleviate this challenge.To address this issue,we genetically edited BnaNRAMP1 in B.napus by targeting three different exon regions,resulting in new germplasm resources with significant differences in Cd accumulation capacity and unaffected yield.Among these,the mutant K140-22,specifically targeting the 7th exon,is distinguished by its substantially reduced Cd accumulation.Further,enzyme assays of the antioxidant defense system in both roots and shoots of K140-22 revealed its enhanced antioxidant activity,which contributes to elucidating the molecular mechanisms of plant tolerance to heavy metal stress.Remarkably,this mutant also maintained equivalent agronomic traits and seed quality,which highlights its potential as a germplasm resource for rapeseed breeding for low Cd accumulation and elevating rapeseed economic value in Cd-contaminated soil.展开更多
Biochar can change the availability and morphology of soil Cd.However,the influence of biochar on Cd chemical form and subcellular fraction in rice is poorly understood,particularly under different irrigation methods....Biochar can change the availability and morphology of soil Cd.However,the influence of biochar on Cd chemical form and subcellular fraction in rice is poorly understood,particularly under different irrigation methods.A pot experiment of biochar application combined with two irrigation methods(continuous flooding and intermittent irrigation,CF and Ⅱ)was conducted.The Cd accumulation,chemical form and subcellular fraction in rice organs and the associated physiological responses were examined.Biochar significantly reduced soil available Cd(30.85-47.26%and 32.35-52.35%)under CF and Ⅱ but increased the Cd content(30.4-63.88%and 13.03-18.59%)in brown rice.Additionally,the Cd content in shoots/grains under Ⅱ was higher than that under CF.Biochar elevated the Cd soluble fraction in roots while lowered the cell wall fraction under both irrigation methods,whereas the opposite result was observed in leaves.Biochar increased water-,ethanol-,and NaCl-extractable Cd in roots meanwhile increased ethanol-extractable Cd in leaves under both irrigation methods.Moreover,the total amount of water-,ethanol-,and NaCl-extractable Cd in rice roots was higher under Ⅱ than under CF.Related hormones and antioxidant enzymes may also be involved in biochar-mediated Cd accumulation in rice grains.Thus,changes in Cd chemical form and subcellular fraction in the root and leaf are the main mechanisms of biochar-induced rice grains Cd accumulation.展开更多
Two pot experiments were conducted under greenhouse conditions to investigate the characteristics of Cd uptake and accumulation by two Cd accumulator oilseed rape varieties and one Indian mustard grown on a loamy soil...Two pot experiments were conducted under greenhouse conditions to investigate the characteristics of Cd uptake and accumulation by two Cd accumulator oilseed rape varieties and one Indian mustard grown on a loamy soil that had been artificially contaminated by different amounts of CdSO\-4(0, 20, 40, 60, 80, 100 mg/kg soil). The relationship between shoot Cd uptake of the two oilseed rape cultivars and the soil Cd concentrations could be simulated via quadratic equations. The curve showed that maximum shoot Cd uptake of Indian mustard was 314.7 μg/pot at soil Cd concentration of 87.8 mg/kg, while maximum uptake of the variety Xikou Huazi was 543.3 μg/pot at soil Cd concentration of 69.1 mg/kg and that of the variety Zhongyou Za-1hao was 576.7 μg/pot at soil Cd concentration of 84.0 mg/kg, suggesting that shoot Cd uptake ability of the two Cd accumulator oilseed rapes was significantly higher than that of the Indian mustard. Xikou Huazi had higher phytoremediation potential for Cd contaminated soil. Shoot Cd accumulation ability of the two Cd accumulator oilseed rapes was correspond and Cd was easier translocated to the shoot than hyperaccumulator Indian mustard as comparation plant. Shoot Cd distribution pattern showed consistent and significant reduction from older leaves to younger ones of two oilseed rapes and Indian mustard. Cd uptake by oilseed rapes in growth prophase was higher than that of growth anaphase.展开更多
Cadmium(Cd) is an element that is nonessential and extremely toxic to both plants and human beings. Soil contaminated with Cd has adverse impacts on crop yields and threatens human health via the food chain. Cultivati...Cadmium(Cd) is an element that is nonessential and extremely toxic to both plants and human beings. Soil contaminated with Cd has adverse impacts on crop yields and threatens human health via the food chain. Cultivation of low-Cd cultivars has been of particular interest and is one of the most cost-effective and promising approaches to minimize human dietary intake of Cd. Low-Cd crop cultivars should meet particular criteria, including acceptable yield and quality, and their edible parts should have Cd concentrations below maximum permissible concentrations for safe consumption, even when grown in Cd-contaminated soil. Several low-Cd cereal cultivars and genotypes have been developed worldwide through cultivar screening and conventional breeding. Molecular markers are powerful in facilitating the selection of low-Cd cereal cultivars. Modern molecular breeding technologies may have great potential in breeding programs for the development of low-Cd cultivars, especially when coupled with conventional breeding. In this review, we provide a synthesis of low-Cd cereal breeding.展开更多
The association between the rhizospheric microbial community and Cd accumulation in rice is poorly understood.A field trial was conducted to investigate the different rhizobacterial communities of two rice cultivars w...The association between the rhizospheric microbial community and Cd accumulation in rice is poorly understood.A field trial was conducted to investigate the different rhizobacterial communities of two rice cultivars with high Cd accumulation(HA)and low Cd accumulation(LA)at four growth stages.Results showed that the Cd content in the roots of the HA cultivar was 1.23-27.53 higher than that of the LA cultivar(0.08-10.5μg/plant)at four stages.The LA cultivar had a significantly lower Cd availability in rhizosphere and a higher quantity of iron plaque(IP)on the root surface than the HA cultivar at four stages.This resulted in the reduction of Cd concentration in IPs and Cd translocation from IP-to-root.Microbial analysis indicated that the LA cultivar formed a distinct rhizobacterial community from the HA cultivar and had lessα-diversity.The rhizosphere of the LA cultivar was enriched in specific bacterial taxa(e.g.,Massilia and Bacillus)involved in Cd immobilization by phosphate precipitation and IP formation by iron oxidization.However,the rhizosphere in the HA cultivar assembled abundant sulfur-oxidizing bacteria(e.g.,Sulfuricurvum)and iron reduction bacteria(Geobacter).They promoted Cd mobilization and reduced IP formation via the metal redox process.This study reveals a potential approach in which specific rhizobacteria decrease or increase Cd accumulation in rice on contaminated soil and provides a new perspective for secure rice production.展开更多
In order to improve the utilization efficiency of heavy metal pollution of farmland,the revitalization of Hunan rice brand,this research worked on 20142016 oriented social extensive collection of 285 varieties of rice...In order to improve the utilization efficiency of heavy metal pollution of farmland,the revitalization of Hunan rice brand,this research worked on 20142016 oriented social extensive collection of 285 varieties of rice,including 98 early rice varieties and 187 late rice varieties.Screening and veri fication of rice varieties with low Cadmium accumulation were studied in Changsha-Zhuzhou-Xiangtan of Hunan Province,and in other typical cadmium polluted area in Hunan Province.12 early rice varieties and 13 late rice varieties were selected as low Cadmium accumulation varieties.Field test showed that,through the screening of varieties(V),irrigation(I)and acidity adjustment(P),the content of cadmium in early rice is 0.064~0.233 mg/kg,and 0.143~0.246 mg/kg in late rice,basically to ensure the content of cadmium in rice to reach the national standard,and to ensure good food security.展开更多
Paddy fields contaminated with cadmium(Cd)present decreased grain yield and produce Cckcontaminated grains.Screening for low-Cd-accumulating cultivars is a useful method to reduce the amount of Cd in the grains.The pr...Paddy fields contaminated with cadmium(Cd)present decreased grain yield and produce Cckcontaminated grains.Screening for low-Cd-accumulating cultivars is a useful method to reduce the amount of Cd in the grains.The present study aimed to examine the roles of the root morphology and an atomy in Cd tran slocati on and accumulati on in rice plants.Twenty・two rice cultivars were used in the first experiment,after which two cultivars[Zixiangnuo(ZXN)and Jinyou T36(JYT36)]were selected and used in subsequent experiments under hydroponic conditions.The results showed that there were significant differences in Cd concentrations in the shoots(ranging from 4 to 100 mg/kg)and the Cd translocation rates(shoot/root)(from 7%to 102%)among the 22 cultivars,and the shoot Cd concentration was significantly correlated with the Cd translocation rate of the 22 cultivars under 0.1 mg/L Cd treatment.Compared with cultivar ZXN,JYT36 had greater root Cd uptake and accumulation but lower shoot Cd accumulation and Cd translocation rate.The number of root tips per surface area of cultivar ZXN was greater than that of JYT36,while the average root diameter was lower than that of JYT36.Compared with ZXN,JYT36 had stronger apoplastic barriers,and the Casparian bands and suberin lamellae in the root endodermis and exodermis were closer to the root apex in both the control and Cd treatments,especially for suberin lamellae in the root exodermis with Cd treatments,with a differenee of 25 mm.The results also showed that,compared with ZXN,JYT36 had greater percentages of Cd bound in cell walls and intracellular Cd but lower Cd concentrations in the apoplastic fluid under the Cd treatment.The results suggested that Cd translocation,rather than root Cd uptake,is a key process that determi nes Cd accumulati on in the rice shoots.The root morphological and an atomical characteristics evidently affect Cd accumulation in the shoots by inhibiting Cd translocation,especially via the apoplastic pathway.It was possible to pre-screen low・Cd・accumulating rice cultivars on the basis of their root morphology,an atomical characteristics and Cd tran slocati on rate at the seedling stage.展开更多
The effects of zinc （Zn） at different spray concentra- tions （0, 500, and 1 000 μmol · L-1 ） on the plant growth, the ac- tivities of antioxidant enzymes chemical forms of cadmium （Cd）, and the accumulatio...The effects of zinc （Zn） at different spray concentra- tions （0, 500, and 1 000 μmol · L-1 ） on the plant growth, the ac- tivities of antioxidant enzymes chemical forms of cadmium （Cd）, and the accumulation of Cd were studied and compared between two varieties, Shijichaotianjiao （SJCTJ） and Yanjiao425 （YJ425） of pepper （Capsicum annuum L.） in Cd-contaminated soil （Cd 10 mg @ kg-1 ）. The activities of catalase （CAT） and peroxidase （POD） were generally enhanced by Zn. However, superoxide dismutase （SOD） decreased. Addition of Zn decreased the ethanol-extract- able Cd, NaCl-extractable Cd, and acetic acid-extractable Cd in the fruit by 34.6%- 55.3%, 2.0%-17.7% and 0.4%-32.9%, and reduced the accumulation of Cd in fruit and plant total Cd by 12.8%- 68.6% and 9.0%-29.3% in both varieties, respectively.展开更多
The tested soils containing different Cd levels were obtained by mixing the normal cultivated soils with the Cd-contaminated soils taken from the paddies near a mine. Five major categories of vegetables, i.e. cucumber...The tested soils containing different Cd levels were obtained by mixing the normal cultivated soils with the Cd-contaminated soils taken from the paddies near a mine. Five major categories of vegetables, i.e. cucumber, cowpea, Bok choy, radish and lettuce, widely planted in the spring and autumn in Hunan Province, were selected for pool-culture experiments. Results showed that the Cd accumulations varied greatly according to the category of vegetables. The Cd accumulations in cucumber and cowpea growing in soils with high Cd levels (1.5 mg/kg) were within the threshold limits of the national standards, meaning that these two categories are safe to grow in Cd-contaminated soils. For either the cucumber or the cowpea category, there were no significant differences in the Cd accumulations of different genotypes. Most of the tested Bok choy and radish cultivars could grow safely in soils whose Cd levels were below 1.0 mg/kg. In comparison, the Cd accumulations in some cultivars tended to increase sharply as the Cd level in the soil went beyond 1.0 mg/kg. Significant variations were also observed in the Cd accumulations of different genotypes with mounting Cd levels in the soil. Besides, there were no positive correlations between Cd accumulations in plants and Cd levels in soils, indicating large fluctuations and poor ecological stability of Bok choy and radish. Therefore, the planting of Bok choy and radish should be strictly evaluated and controlled in Cdcontaminated regions. The Cd contents of most celtuce cultivars growing in mildlycontaminated soils had already exceeded the threshold limit. Therefore, it is not safe for celtuce to grow in Cd-contaminated environments.展开更多
Rice (Oryza sativa) is a staple food for over half of the global population, with its cultivation spanning diverse agroecological regions. Cadmium (Cd) contamination has emerged as a significant challenge to rice cult...Rice (Oryza sativa) is a staple food for over half of the global population, with its cultivation spanning diverse agroecological regions. Cadmium (Cd) contamination has emerged as a significant challenge to rice cultivation, as Cd contamination in rice grains poses serious health risks, such as kidney damage, skeletal issues, and cancer (Noor et al., 2024). Cd enters the rice plant primarily through Cd-contaminated soil and subsequently accumulates in various tissues, including grains. Unfortunately, minimizing Cd accumulation in rice grains remains a significant challenge despite extensive efforts (Zou et al., 2021). Among various mitigation strategies, breeding and promoting low-Cd rice varieties represents the most cost-effective and sustainable approach to minimize Cd exposure in human diets. Considering the importance of this issue, researchers have explored agronomic interventions, but their limited success highlights the urgency for genetic solutions. Consequently, in recent years, intensive research efforts have been directed toward developing low-Cd rice varieties, leading to the identification of promising genetic solutions to reduce Cd levels in rice. More than 30 transporter genes have been identified as players for Cd transport in rice. Among them, OsNRAMP5 and OsHMA3 exert dominant effects on grain-Cd accumulation, while other transporters have minor effects on this process. However, the precise regulatory mechanisms underlying grain-Cd accumulation remain largely elusive. Thus, deciphering the genetic network involved in grain-Cd accumulation is essential for the development of low-Cd rice varieties, offering a sustainable strategy to mitigate the risk associated with Cd accumulation in rice grain.展开更多
A pot experiment was carried out by growing 29 different genotypes （Amaranthus spp.） of vegetable amaranth under low- （0.12 mg. kg-1） and middle- （0.40 mg · kg-1） cadmium （Cd） exposure. The result showed ...A pot experiment was carried out by growing 29 different genotypes （Amaranthus spp.） of vegetable amaranth under low- （0.12 mg. kg-1） and middle- （0.40 mg · kg-1） cadmium （Cd） exposure. The result showed that amaranth was vulnerable to cadmium （Cd） contamination in soil. Variations of Cd concentrations in both roots and edible parts among genotypes were significant （P 〈 0.001） in both treatments. Cd concentrations in edible parts of the tested genotypes grown under low- and middle-Cd levels were significantly correlated （p 〈 0.01）, implying that Cd- accumulating property of amaranth is genotype-dependent. Differences in Cd chemical forms between cv. Nanxing- dayemashixian （cv. Nan）, a selected typical pollution-safe cultivar （Cd-PSC）, and cv. Pennongjianyexian （cv. Pen）, a selected typical non-Cd-PSC, under different Cd exposure conditions were compared. It was found that the alternation of Cd in FNaC1 （Cd form extracted by 1 mol.L-1NaC1） may be a key factor in regulating Cd accumulation of different amaranth genotypes and that the protein-binding Cd is considered to be associated with Cd translocation. The results indicated that amaranth is capable of enduring high level of Cd pollution when grown as vegetable crop, and accordingly, consuming vegetable amaranth would bring high health risk. Therefore, adopting Cd-PSC strategy would help reducing the risk of Cd pollution in amaranth. In this study, cv. Nan was identified as a Cd-PSC and recommended to be applied production practice.展开更多
基金support from the National Natural Science Foundation of China(U20A2024)the National Key Research and Development Program of China(2023YFD2301300).
文摘Cadmium(Cd)uptake by rice plants and its subsequent movement through food chains pose a notable risk to the health of both plants and humans.Therefore,understanding the fundamental mechanisms underlying the uptake and movement process is essential.Through transcriptome analysis,we found that numerous abscisic acid(ABA)-related genes responded to Cd stress.Exogenous application of ABA significantly reduced Cd accumulation in the shoots and roots of rice plants.The increased ascorbate peroxidase(APX)enzyme activity,decreased H2O2 content,and elevated Cd tolerance index collectively suggest that ABA may mitigate the toxicity of Cd in rice plants.Further study revealed that exogenous ABA reduced Cd accumulation by regulating Cd transport and cell wall sequestration.Consistently,mutation of the ABA signaling factor OsABI5 resulted in a significant increase in Cd accumulation in shoots.Moreover,foliar spraying of ABA during the grain-filling stage significantly reduced Cd accumulation in rice grains,which was attributed mainly to decreased Cd uptake and the inhibition of Cd transportation from roots to shoots and from leaves to grains.These findings elucidate the underlying mechanisms of the ABA-mediated response to Cd stress in rice and provide a practical reference for coping with Cd pollution in farmlands.
基金supported by the National Natural Science Foundation of China(31560122)the Guangxi Key Laboratory of Agro-Environment and Agric-Products Safety,China。
文摘The addition of silicon(Si)and organic fertilizers to soil conditioners can inhibit the transfer of heavy metal ions from soil to crops.However,it is not clear how Si and organic fertilizers affect soil properties and the micro-ecological environment and thereby reduce cadmium(Cd)accumulation in rice.In this study,the effects of L-type soil conditioners containing Si and organic fertilizers on bacterial and fungal community diversity,soil pH,organic matter,and available Si were analyzed with field experiments at two sites in Liuzhou City and Hezhou City,respectively,in Guangxi,China.With the increase of Si and organic fertilizer content in soil conditioner,rice yield respectively increased by 16.8–25.8 and 6.8–13.1%,and rice Cd content decreased significantly by 8.2–21.1 and 10.8–40.6%,respectively,at the two experimental sites.Soil microbiome analysis showed that the increase in abundance of Firmicutes and Actinobacteriota bacteria associated with Cd adsorption and sequestration,and Basidiomycota fungal populations associated with degradation of macromolecules favored the inhibition of soil Cd activity(soil exchangeable Cd decreased by 14.4–14.8 and 18.1–20.6%).This was associated with an increase in organic matter and Si content caused by applying soil conditioners.In conclusion,L-type soil conditioners,rich in Si and organic fertilizer,can reduce soil Cd bioavailability by regulating the dominant Cd passivating flora in the soil and ultimately reduce Cd accumulation in rice.
基金supported by the National Key Research and Development Program of China(2022YFD1601502 and 2023YFD1200202)the National Natural Science Foundation of China(32272167 and 32341028)+1 种基金the Sichuan Science and Technology Program,China(2022ZDZX0015)the Fundamental Research Funds for the Central Universities,China(SCU2019D013)。
文摘Brassica napus,one of the most important oil crops cultivated globally,is severely impacted by prolonged soil contamination with cadmium(Cd),resulting in decreased yields and poor seed quality.This crop exhibits a high adsorption capacity for Cd,making creating seed resources with low Cd accumulation an essential strategy to alleviate this challenge.To address this issue,we genetically edited BnaNRAMP1 in B.napus by targeting three different exon regions,resulting in new germplasm resources with significant differences in Cd accumulation capacity and unaffected yield.Among these,the mutant K140-22,specifically targeting the 7th exon,is distinguished by its substantially reduced Cd accumulation.Further,enzyme assays of the antioxidant defense system in both roots and shoots of K140-22 revealed its enhanced antioxidant activity,which contributes to elucidating the molecular mechanisms of plant tolerance to heavy metal stress.Remarkably,this mutant also maintained equivalent agronomic traits and seed quality,which highlights its potential as a germplasm resource for rapeseed breeding for low Cd accumulation and elevating rapeseed economic value in Cd-contaminated soil.
基金National Natural Science Foundation of China(32201889)Jiangsu Funding Program for Excellent Postdoctoral Talent(2022ZB627)+1 种基金Jiangsu Technical System of Rice Industry(JATS[2021]485)Special Funds of the Rice Industry System of Jiangxi Province(JXARS-02-03).
文摘Biochar can change the availability and morphology of soil Cd.However,the influence of biochar on Cd chemical form and subcellular fraction in rice is poorly understood,particularly under different irrigation methods.A pot experiment of biochar application combined with two irrigation methods(continuous flooding and intermittent irrigation,CF and Ⅱ)was conducted.The Cd accumulation,chemical form and subcellular fraction in rice organs and the associated physiological responses were examined.Biochar significantly reduced soil available Cd(30.85-47.26%and 32.35-52.35%)under CF and Ⅱ but increased the Cd content(30.4-63.88%and 13.03-18.59%)in brown rice.Additionally,the Cd content in shoots/grains under Ⅱ was higher than that under CF.Biochar elevated the Cd soluble fraction in roots while lowered the cell wall fraction under both irrigation methods,whereas the opposite result was observed in leaves.Biochar increased water-,ethanol-,and NaCl-extractable Cd in roots meanwhile increased ethanol-extractable Cd in leaves under both irrigation methods.Moreover,the total amount of water-,ethanol-,and NaCl-extractable Cd in rice roots was higher under Ⅱ than under CF.Related hormones and antioxidant enzymes may also be involved in biochar-mediated Cd accumulation in rice grains.Thus,changes in Cd chemical form and subcellular fraction in the root and leaf are the main mechanisms of biochar-induced rice grains Cd accumulation.
文摘Two pot experiments were conducted under greenhouse conditions to investigate the characteristics of Cd uptake and accumulation by two Cd accumulator oilseed rape varieties and one Indian mustard grown on a loamy soil that had been artificially contaminated by different amounts of CdSO\-4(0, 20, 40, 60, 80, 100 mg/kg soil). The relationship between shoot Cd uptake of the two oilseed rape cultivars and the soil Cd concentrations could be simulated via quadratic equations. The curve showed that maximum shoot Cd uptake of Indian mustard was 314.7 μg/pot at soil Cd concentration of 87.8 mg/kg, while maximum uptake of the variety Xikou Huazi was 543.3 μg/pot at soil Cd concentration of 69.1 mg/kg and that of the variety Zhongyou Za-1hao was 576.7 μg/pot at soil Cd concentration of 84.0 mg/kg, suggesting that shoot Cd uptake ability of the two Cd accumulator oilseed rapes was significantly higher than that of the Indian mustard. Xikou Huazi had higher phytoremediation potential for Cd contaminated soil. Shoot Cd accumulation ability of the two Cd accumulator oilseed rapes was correspond and Cd was easier translocated to the shoot than hyperaccumulator Indian mustard as comparation plant. Shoot Cd distribution pattern showed consistent and significant reduction from older leaves to younger ones of two oilseed rapes and Indian mustard. Cd uptake by oilseed rapes in growth prophase was higher than that of growth anaphase.
基金Project supported by the Key Research Foundation of Science and Technology Department of Zhejiang Province of China(No.2016C02050-9-7)。
文摘Cadmium(Cd) is an element that is nonessential and extremely toxic to both plants and human beings. Soil contaminated with Cd has adverse impacts on crop yields and threatens human health via the food chain. Cultivation of low-Cd cultivars has been of particular interest and is one of the most cost-effective and promising approaches to minimize human dietary intake of Cd. Low-Cd crop cultivars should meet particular criteria, including acceptable yield and quality, and their edible parts should have Cd concentrations below maximum permissible concentrations for safe consumption, even when grown in Cd-contaminated soil. Several low-Cd cereal cultivars and genotypes have been developed worldwide through cultivar screening and conventional breeding. Molecular markers are powerful in facilitating the selection of low-Cd cereal cultivars. Modern molecular breeding technologies may have great potential in breeding programs for the development of low-Cd cultivars, especially when coupled with conventional breeding. In this review, we provide a synthesis of low-Cd cereal breeding.
基金supported by the National Natural Science Foundation of China(No.41907032)the Major Science,and Technology Programs of Changsha(No.kq2006026)the High Technology Industry S&T Innovation Leading Project of Hunan Province(No.2020NK2001)。
文摘The association between the rhizospheric microbial community and Cd accumulation in rice is poorly understood.A field trial was conducted to investigate the different rhizobacterial communities of two rice cultivars with high Cd accumulation(HA)and low Cd accumulation(LA)at four growth stages.Results showed that the Cd content in the roots of the HA cultivar was 1.23-27.53 higher than that of the LA cultivar(0.08-10.5μg/plant)at four stages.The LA cultivar had a significantly lower Cd availability in rhizosphere and a higher quantity of iron plaque(IP)on the root surface than the HA cultivar at four stages.This resulted in the reduction of Cd concentration in IPs and Cd translocation from IP-to-root.Microbial analysis indicated that the LA cultivar formed a distinct rhizobacterial community from the HA cultivar and had lessα-diversity.The rhizosphere of the LA cultivar was enriched in specific bacterial taxa(e.g.,Massilia and Bacillus)involved in Cd immobilization by phosphate precipitation and IP formation by iron oxidization.However,the rhizosphere in the HA cultivar assembled abundant sulfur-oxidizing bacteria(e.g.,Sulfuricurvum)and iron reduction bacteria(Geobacter).They promoted Cd mobilization and reduced IP formation via the metal redox process.This study reveals a potential approach in which specific rhizobacteria decrease or increase Cd accumulation in rice on contaminated soil and provides a new perspective for secure rice production.
基金Supported by Pilot Project of Remediation of Heavy Metal Polluted Farmland and Planting Adjustment for Crops Structure in Hunan~~
文摘In order to improve the utilization efficiency of heavy metal pollution of farmland,the revitalization of Hunan rice brand,this research worked on 20142016 oriented social extensive collection of 285 varieties of rice,including 98 early rice varieties and 187 late rice varieties.Screening and veri fication of rice varieties with low Cadmium accumulation were studied in Changsha-Zhuzhou-Xiangtan of Hunan Province,and in other typical cadmium polluted area in Hunan Province.12 early rice varieties and 13 late rice varieties were selected as low Cadmium accumulation varieties.Field test showed that,through the screening of varieties(V),irrigation(I)and acidity adjustment(P),the content of cadmium in early rice is 0.064~0.233 mg/kg,and 0.143~0.246 mg/kg in late rice,basically to ensure the content of cadmium in rice to reach the national standard,and to ensure good food security.
基金supported by the National Key Research and Development Program of China(Grant No.2018YFD0800700)the National Natural Science Foundation of China(Grant No.31670409)+1 种基金the General Research Fund Proposal of Hong Kong,China(Grant No.RG21/2020-2021R)the Faculty of Liberal Arts and Social Sciences of the Education University of Hong Kong,China(Grant No.04548(IRS-10)).
文摘Paddy fields contaminated with cadmium(Cd)present decreased grain yield and produce Cckcontaminated grains.Screening for low-Cd-accumulating cultivars is a useful method to reduce the amount of Cd in the grains.The present study aimed to examine the roles of the root morphology and an atomy in Cd tran slocati on and accumulati on in rice plants.Twenty・two rice cultivars were used in the first experiment,after which two cultivars[Zixiangnuo(ZXN)and Jinyou T36(JYT36)]were selected and used in subsequent experiments under hydroponic conditions.The results showed that there were significant differences in Cd concentrations in the shoots(ranging from 4 to 100 mg/kg)and the Cd translocation rates(shoot/root)(from 7%to 102%)among the 22 cultivars,and the shoot Cd concentration was significantly correlated with the Cd translocation rate of the 22 cultivars under 0.1 mg/L Cd treatment.Compared with cultivar ZXN,JYT36 had greater root Cd uptake and accumulation but lower shoot Cd accumulation and Cd translocation rate.The number of root tips per surface area of cultivar ZXN was greater than that of JYT36,while the average root diameter was lower than that of JYT36.Compared with ZXN,JYT36 had stronger apoplastic barriers,and the Casparian bands and suberin lamellae in the root endodermis and exodermis were closer to the root apex in both the control and Cd treatments,especially for suberin lamellae in the root exodermis with Cd treatments,with a differenee of 25 mm.The results also showed that,compared with ZXN,JYT36 had greater percentages of Cd bound in cell walls and intracellular Cd but lower Cd concentrations in the apoplastic fluid under the Cd treatment.The results suggested that Cd translocation,rather than root Cd uptake,is a key process that determi nes Cd accumulati on in the rice shoots.The root morphological and an atomical characteristics evidently affect Cd accumulation in the shoots by inhibiting Cd translocation,especially via the apoplastic pathway.It was possible to pre-screen low・Cd・accumulating rice cultivars on the basis of their root morphology,an atomical characteristics and Cd tran slocati on rate at the seedling stage.
基金Supported by the National Science and Technology Pillar Program of China(No.2007BAD87B10)China Agriculture Research System(CARS-25-C-05)
文摘The effects of zinc （Zn） at different spray concentra- tions （0, 500, and 1 000 μmol · L-1 ） on the plant growth, the ac- tivities of antioxidant enzymes chemical forms of cadmium （Cd）, and the accumulation of Cd were studied and compared between two varieties, Shijichaotianjiao （SJCTJ） and Yanjiao425 （YJ425） of pepper （Capsicum annuum L.） in Cd-contaminated soil （Cd 10 mg @ kg-1 ）. The activities of catalase （CAT） and peroxidase （POD） were generally enhanced by Zn. However, superoxide dismutase （SOD） decreased. Addition of Zn decreased the ethanol-extract- able Cd, NaCl-extractable Cd, and acetic acid-extractable Cd in the fruit by 34.6%- 55.3%, 2.0%-17.7% and 0.4%-32.9%, and reduced the accumulation of Cd in fruit and plant total Cd by 12.8%- 68.6% and 9.0%-29.3% in both varieties, respectively.
文摘The tested soils containing different Cd levels were obtained by mixing the normal cultivated soils with the Cd-contaminated soils taken from the paddies near a mine. Five major categories of vegetables, i.e. cucumber, cowpea, Bok choy, radish and lettuce, widely planted in the spring and autumn in Hunan Province, were selected for pool-culture experiments. Results showed that the Cd accumulations varied greatly according to the category of vegetables. The Cd accumulations in cucumber and cowpea growing in soils with high Cd levels (1.5 mg/kg) were within the threshold limits of the national standards, meaning that these two categories are safe to grow in Cd-contaminated soils. For either the cucumber or the cowpea category, there were no significant differences in the Cd accumulations of different genotypes. Most of the tested Bok choy and radish cultivars could grow safely in soils whose Cd levels were below 1.0 mg/kg. In comparison, the Cd accumulations in some cultivars tended to increase sharply as the Cd level in the soil went beyond 1.0 mg/kg. Significant variations were also observed in the Cd accumulations of different genotypes with mounting Cd levels in the soil. Besides, there were no positive correlations between Cd accumulations in plants and Cd levels in soils, indicating large fluctuations and poor ecological stability of Bok choy and radish. Therefore, the planting of Bok choy and radish should be strictly evaluated and controlled in Cdcontaminated regions. The Cd contents of most celtuce cultivars growing in mildlycontaminated soils had already exceeded the threshold limit. Therefore, it is not safe for celtuce to grow in Cd-contaminated environments.
基金supported by Ministry of Science and Technology of China(2023YFD1200901)Research Programs from Jiangsu government(ZSBBL-KY2023-01,PAPD,and Qing Lan Project).
文摘Rice (Oryza sativa) is a staple food for over half of the global population, with its cultivation spanning diverse agroecological regions. Cadmium (Cd) contamination has emerged as a significant challenge to rice cultivation, as Cd contamination in rice grains poses serious health risks, such as kidney damage, skeletal issues, and cancer (Noor et al., 2024). Cd enters the rice plant primarily through Cd-contaminated soil and subsequently accumulates in various tissues, including grains. Unfortunately, minimizing Cd accumulation in rice grains remains a significant challenge despite extensive efforts (Zou et al., 2021). Among various mitigation strategies, breeding and promoting low-Cd rice varieties represents the most cost-effective and sustainable approach to minimize Cd exposure in human diets. Considering the importance of this issue, researchers have explored agronomic interventions, but their limited success highlights the urgency for genetic solutions. Consequently, in recent years, intensive research efforts have been directed toward developing low-Cd rice varieties, leading to the identification of promising genetic solutions to reduce Cd levels in rice. More than 30 transporter genes have been identified as players for Cd transport in rice. Among them, OsNRAMP5 and OsHMA3 exert dominant effects on grain-Cd accumulation, while other transporters have minor effects on this process. However, the precise regulatory mechanisms underlying grain-Cd accumulation remain largely elusive. Thus, deciphering the genetic network involved in grain-Cd accumulation is essential for the development of low-Cd rice varieties, offering a sustainable strategy to mitigate the risk associated with Cd accumulation in rice grain.
文摘A pot experiment was carried out by growing 29 different genotypes （Amaranthus spp.） of vegetable amaranth under low- （0.12 mg. kg-1） and middle- （0.40 mg · kg-1） cadmium （Cd） exposure. The result showed that amaranth was vulnerable to cadmium （Cd） contamination in soil. Variations of Cd concentrations in both roots and edible parts among genotypes were significant （P 〈 0.001） in both treatments. Cd concentrations in edible parts of the tested genotypes grown under low- and middle-Cd levels were significantly correlated （p 〈 0.01）, implying that Cd- accumulating property of amaranth is genotype-dependent. Differences in Cd chemical forms between cv. Nanxing- dayemashixian （cv. Nan）, a selected typical pollution-safe cultivar （Cd-PSC）, and cv. Pennongjianyexian （cv. Pen）, a selected typical non-Cd-PSC, under different Cd exposure conditions were compared. It was found that the alternation of Cd in FNaC1 （Cd form extracted by 1 mol.L-1NaC1） may be a key factor in regulating Cd accumulation of different amaranth genotypes and that the protein-binding Cd is considered to be associated with Cd translocation. The results indicated that amaranth is capable of enduring high level of Cd pollution when grown as vegetable crop, and accordingly, consuming vegetable amaranth would bring high health risk. Therefore, adopting Cd-PSC strategy would help reducing the risk of Cd pollution in amaranth. In this study, cv. Nan was identified as a Cd-PSC and recommended to be applied production practice.
