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Abscisic acid (ABA) is an important hormone that can regulate the heavy-metal uptake of plants. In this study, exogenous ABA was applied to lettuce (Lactuca sativa) grown under cadmium (Cd)-stress conditions, and the effects of exogenous ABA on the growth and Cd accumulation of lettuce were evaluated. The results showed that treatment of Cd significantly decreased biomass and increased Cd content of lettuce compared with the control. The shoot biomass increased after spraying 1, 5 and 10 μmol/L ABA, and the root biomass increased after spraying 1–20 μmol/L ABA compared with the treatment of Cd. The Cd content in shoots significantly decreased when exposed to different ABA concentrations. The lowest Cd content in shoots of lettuce was produced by the ABA concentration of 5 μmol/L, with decreased by 23.60% compared with the treatment of Cd. Therefore, spraying ABA effectively alleviated Cd toxicity and reduced Cd uptake in the edible parts of lettuce, and 5 μmol/L ABA was the optimal dose. [ABSTRACT FROM AUTHOR]

A pot experiment was conducted to study the effects of intercropping with the cadmium (Cd) hyperaccumulators Galinsoga parviflora, Bidens pilosa, Cosmos sulphureus and Solanum nigrum on the growth and Cd accumulation of water spinach (Ipomoea aquatica Forsk). The results show that intercropping with B. pilosa improved biomass and photosynthetic pigment contents of water spinach, but intercropping with G. parviflora, C. sulphureus and S. nigrum shaded water spinach; thus, the growth of water spinach was inhibited. When compared with monoculture, the Cd contents in roots and shoots of water spinach were reduced by intercropping with B. pilosa, C. sulphureus and S. nigrum, and the shoot Cd content decreased by 27.93%, 3.12% and 5.30%, respectively. Intercropping with G. parviflora reduced the root Cd content in water spinach, but increased the shoot Cd content. Therefore, intercropping with B. pilosa could promote the growth and reduce the Cd accumulation of water spinach. [ABSTRACT FROM AUTHOR]

In this study, pot experiments were conducted to study the effects of reciprocal grafting on the growth and Cd accumulation in post-grafting generations of two cherry tomatoes – red (Red cherry 5-5-1-1) and yellow (RTY-3-2) cherry tomatoes. Six treatments, which consisted of ungrafted red cherry tomato (R-CK), ungrafted yellow cherry tomato (Y-CK), red cherry tomato as rootstock (R-rootstock), red cherry tomato as scion (R-scion), yellow cherry tomato as rootstock (Y- rootstock), and yellow cherry tomato as scion (Y-scion) were utilised. The results showed that grafting significantly decreased the root biomass of Y- rootstock and Y-scion as compared to that of Y-CK, but there were no differences in the shoot biomass. Compared with that of Y-CK, grafting increased the root Cd content of the post-grafting generations, specifically, Y- rootstock and Y-scion increased by 54.44% and 52.96%, respectively. There were no significant differences in the shoot Cd content of Y- rootstock, Y-scion, and Y-CK. The root, stem, leaf, and shoot biomass of R-rootstock increased by 14.17%, 76.23%, 36.47%, and 21.72%, respectively, as compared with that of R-CK. However, grafting had no significant effect on the root, stem, leaf, and shoot biomass of R-scion. Grafting significantly increased the root Cd content of R-rootstock. However, grafting significantly decreased the shoot Cd content of R-rootstock, with the value 26.18% lower than that of R-CK. The root Cd content of R-scion significantly increased compared with the R-CK, and the shoot Cd content had no differences. Therefore, the reciprocal grafting of the two cherry tomatoes promoted the growth and reduced the Cd uptake of R-rootstock. Findings from this study could be used to provide a reference for the safe production of tomatoes in heavy metal-contaminated soils. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effects of spraying an algal biostimulant at different concentrations (0, 600-, 900-, 1200-, and 1500-fold dilutions) on the growth and cadmium (Cd) accumulation characteristics of accumulator plant Nasturtium officinale. In a pot experiment, application of the algal biostimulant at all concentrations promoted the growth of N. officinale by increasing the root and shoot biomasses, and the 600-fold dilution of the algal biostimulant had the strongest effect. At all concentrations, the algal biostimulant had no significant effect on the Cd content in roots of N. officinale, and increased the Cd extraction by roots. However, all concentrations of the algal biostimulant except for the 1500-fold dilution decreased the Cd content in shoots and Cd extraction by shoots. The N. officinale plants treated with the 600-fold dilution of the algal biostimulant had the lowest shoot Cd contents and Cd extraction by shoots. The algal biostimulant also increased the contents of photosynthetic pigments (chlorophyll a, total chlorophyll, and carotenoids) in leaves of N. officinale to varying degrees. Different concentrations of algal biostimulant reduced the superoxide dismutase activity, peroxidase activity, and malondialdehyde content of N. officinale, but enhanced the catalase activity, soluble protein content, and relative conductivity. Overall, the 600-fold dilution had the strongest effect on the growth and Cd accumulation characteristics of N. officinale, but did not enhance the phytoremediation ability of N. officinale for growth in Cd-contaminated soil. These results show that this algal biostimulant can promote the growth and reduce the Cd uptake of N. officinale, which is benefit for N. officinale safety production as a wild vegetable in Cd-contaminated soils. [ABSTRACT FROM AUTHOR]

Cuttings are asexual reproduction, and different vegetative organs of the plant can be selected as cuttings to grow into a new plant. Growth and cadmium (Cd) accumulation of cuttings taken from tomato (Solanum lycopersicum) plants non-grafted or grafted onto five different rootstocks were studied in a pot experiment. 'Zhongyanhong 6ʹ and 'Hongyu F1ʹ were non-grafted (CK) and were grafted onto Solanum torvum, Totosga, 'Dalishengen', 'Banzhen 18ʹ and 'Guozhen 1ʹ, respectively, planted in pots without Cd-contaminated soil. Cuttings were taken after one month, then grown in Cd-contaminated soil (10 mg kg−1) for three months. In 'Zhongyanhong 6ʹ cuttings, compared with non-grafted, grafting onto five rootstocks increased plant dry weight, grafting onto 'Banzhen 18ʹ and S. torvum increased plant height, grafting onto 'Banzhen 18ʹ and 'Guozhen 1' increased fruit fresh weight, grafting onto 'Guozhen 1ʹ and 'Dalishengen' reduced Cd content in fruit. In 'Hongyu F1ʹ cuttings, compared with non-grafted, grafting onto five rootstocks increased plant dry weight, grafting onto Totosga increased plant height, grafting onto S. torvum and Totosga increased fruit fresh weight, grafting onto 'Banzhen 18ʹ, 'Dalishengen', S. torvum and Totosga decreased Cd content in fruit. Cutting after grafting affects growth and Cd accumulation of tomato, which can provide a theoretical basis for the safe production of nightshade vegetables. [ABSTRACT FROM AUTHOR]

To identify whether the auxin treatment could promote the growth and reduce the cadmium (Cd) of fruit trees, the effects of different concentrations of indole acetic acid (IAA, one of the auxin) on the biomass, Cd content, photosynthetic pigment content, photosynthetic characteristics, antioxidant enzyme activity, and soluble sugars content in Cyphomandra betacea seedlings under Cd stress were studied. As the IAA concentration increased, the biomass, photosynthetic pigment content, soluble sugars content, and net photosynthetic rate of C. betacea seedlings tended to first increase and then decrease, with maximum values in the 60 mg/L IAA treatment. The Cd contents in different organs decreased and then increased with increasing IAA concentrations, with the minimum value in the 60 mg/L IAA treatment. Compared with the control, IAA treatments enhanced the activities of peroxidase and superoxide dismutase in the leaves of C. betacea seedlings and decreased the soluble protein content. Therefore, IAA treatments promoted growth, enhanced Cd resistance, and decreased the Cd content in C. betacea. The 60 mg/L IAA treatment was the most effective for promoting growth and decreasing the Cd content in C. betacea. [ABSTRACT FROM AUTHOR]

Straw of Solanum photeinocarpum accessions originating from two climatic-ecological zones (Chengdu, in the Mountain-Central Subtropical-Cold Zone; and Ya'an, in the Central Subtropical-Long Spring and Summer-Drought Zone) and their reciprocal F1 hybrids were added to Cd-contaminated soil, and their effects on the growth and Cd accumulation of lettuce were evaluated. Addition of S. photeinocarpum straw significantly increased biomass and decreased Cd content of lettuce, especially the straw of F1 hybrids raised from a Chengdu pollen donor. Shoot biomass was increased by 26.87%and the shoot Cd content was decreased by 25.86% compared with those of the control. The chlorophyll content and net photosynthetic rate were increased in response to the addition of S. photeinocarpum straw, and the effects of straw of reciprocal F1 hybrids were superior to those of the parents. Application of S. photeinocarpum straw promoted osmoticas (soluble sugar, soluble protein, free proline) contents and activities of antioxidant enzymes [superoxide dismutase (SOD), peroxidase (POD), catalase (CAT)], reduced malondialdehyde (MDA) accumulation, and thus effectively improved the resistance of lettuce to Cd stress. S. photeinocarpum straw increased soil pH and organic matter content, and consequently decreased soil exchangeable Cd content, the strongest effect was achieved by application of S. photeinocarpum straw of reciprocal F1 hybrids raised from a Chengdu pollen donor, in response to which the soil exchangeable Cd content was decreased by 29.62% compared with that of the control. Therefore, the application of S. photeinocarpum straw in Cd-contaminated soil promoted growth and reduced the risk of Cd contamination of lettuce plants. The effects of straw from reciprocal F1 hybrids derived from a Chengdu pollen donor were superior to those of straw from the parents, and thus may be effectively used to improve the safe production of lettuce in Cd-contaminated soil. [ABSTRACT FROM AUTHOR]

Two pot experiments were conducted to study the effects of intercropping with cadmium (Cd) accumulator plant Eclipta prostrata and hyperaccumulator plant Crassocephalum crepidioides on the growth and Cd accumulation of tomato seedlings. In the preliminary experiment, intercropping with E. prostrata and C. crepidioides promoted the growth and decreased the Cd content in roots and shoots of tomato seedlings. In the further experiment, intercropping with E. prostrata and C. crepidioides had the same effects on the growth and Cd content of tomato seedlings as the preliminary experiment. In the further experiment, when three plant species (E. prostrate, C. crepidioides and tomato) intercropping together, the root and shoot biomasses of tomato seedlings got the maximum, and the Cd content in tomato seedlings got the minimum. Compared with the monoculture of tomato, three plant species intercropping increased the root and shoot biomasses of tomato seedlings by 49.28% and 64.19%, respectively, and decreased the Cd contents in roots and shoots of tomato seedlings by 17.35% and 22.35%, respectively. Intercropping with E. prostrata and C. crepidioides also increased the photosynthetic pigment content and enhanced the antioxidant enzyme activity of tomato seedlings. For accumulator and hyperaccumulator plants, intercropping with tomato inhibited the growth of E. prostrata and C. crepidioides, while increased the Cd content in two plant species. Therefore, intercropping with E. prostrata and C. crepidioides could promote the growth and reduce the Cd uptake of tomato seedlings, and three plant species intercropping together was the best combination. [ABSTRACT FROM AUTHOR]

The study aimed at accessing the effects of mowing on the growth and cadmium (Cd) accumulation of the first post-grafting generation of potential Cd-hyperaccumulator plant Solanum photeinocarpum through the pot and plot experiments. Four grafting treatments were employed such as ungrafted (UG), self-rooted grafting by the same S. photeinocarpum seedling (SG), self-rooted grafting by two different development stages of S. photeinocarpum seedlings (DG), and grafting on the rootstock of wild potato (PG). The biomass, Cd content, and Cd extraction amount of S. photeinocarpum shoots significantly decreased with the increase of mowing times in the pot and plot experiments. The order of the grafting on the biomass, Cd content, and Cd extraction amountof in the first, second, third mowing shoots were PG > DG > SG > UG. For the Cd extraction amountof total moving shoots, SG, DG, and PG increased by 20.42%, 35.54%, and 52.94%, respectively, in the pot experiment, and increased by 11.56%, 26.28%, and 44.90%, respectively, in the plot experiment, compared with the UG. Therefore, mowing provides an insight into the phytoremediation ability of S. photeinocarpum to Cd. [ABSTRACT FROM AUTHOR]

To study the cadmium (Cd)-accumulation characteristics of the post-grafting generation of Cyphomandra betacea (Cav.) Sendt., the seeds of C. betacea grafted on Solanum nigrum L., tomato, and eggplant rootstocks were collected and planted in Cd-contaminated soil. Compared with seeds of ungrafted seedlings, the S. nigrum rootstock increased the shoot biomass of the post-grafting generation of C. betacea seedlings, while eggplant and tomato rootstocks decreased or had no significant effects. Only the S. nigrum rootstock increased the chlorophyll a content, net photosynthetic rate, and stomatal conductance of the post-grafting generation of C. betacea seedlings, while the other rootstocks decreased or had no significant effects on these photosynthetic parameters. The S. nigrum rootstock enhanced the superoxide dismutase and catalase activities, and soluble protein content, of the post-grafting generation of C. betacea seedlings, while the other rootstocks reduced or had no significant effects on these parameters. The three rootstocks decreased the Cd contents in different organs of the post-grafting generation of C. betacea seedlings, and the order of treatments was ungrafted > tomato rootstock > eggplant rootstock > S. nigrum rootstock. Therefore, S. nigrum was the best rootstock to promote the growth and decrease the Cd contents in post-grafting generation of C. betacea, and this can benefit C. betacea production in Cd-contaminated areas. [ABSTRACT FROM AUTHOR]

Farmland and mining ecotypes of the potential cadmium (Cd)-hyperaccumulator Solanum photeinocarpum were collected to study the effects of reciprocal grafting on the growth of, and Cd accumulation in, the post-grafting generations. The post generations of the following plant materials were evaluated in a pot experiment: the un-grafted farmland ecotype, grafted plants with the farmland ecotype as the scion or the rootstock, the un-grafted mining ecotype, and grafted plants with the mining ecotype as the scion or the rootstock. The results showed that reciprocal grafting increased the biomass, the activities of superoxide dismutase, peroxidase, and catalase, and the soluble protein content in the post-grafting generations of both ecotypes S. photeinocarpum. Reciprocal grafting also increased the Cd content in, and amount of Cd extracted by, the post-grafting generations of both ecotypes S. photeinocarpum as a result of lower soil pH and higher soil available Cd concentrations. Additionally, grafting affected the DNA methylation levels by inducing hypermethylation or demethylation in the post-grafting generation. Therefore, reciprocal grafting can enhance the Cd accumulation (phytoremediation) capacity of post-grafting generations of both ecotypes S. photeinocarpum by affecting DNA methylation levels. [ABSTRACT FROM AUTHOR]

The contamination of orchard by cadmium (Cd) has recently increased in severity. To decrease the Cd content in fruit tree, a pot-based experiment was conducted to study the effects of intercropping with two Solanum species (Solanum alatum and Solanum diphyllum) on the growth and Cd accumulation of Cyphomandra betacea seedlings. The data revealed that intercropping with two Solanum species significantly increased the biomass, photosynthetic pigment contents, antioxidant enzyme activities, and soluble protein contents of C. betacea seedlings under Cd stress condition. The intercropping significantly decreased the Cd content in C. betacea seedlings. However, the intercropping significantly decreased the S. alatum and S. diphyllum biomasses, while increased the Cd content and accumulation in the roots and shoots of two Solanum species, and the Cd uptake by S. alatum was lower than that of S. diphyllum. Therefore, intercropping with these two Solanum species, especially S. diphyllum, may promote the growth and decrease the Cd content in C. betacea. [ABSTRACT FROM AUTHOR]

To determine whether grafting increases cadmium (Cd) accumulation in the post-grafting generation of hyperaccumulator plants, the effects of grafting on Cd accumulation characteristics of post-grafting generations of a potential Cd-hyperaccumulator Solanum photeinocarpum were evaluated in pot and field experiments. The following four grafting combinations were examined: ungrafted (UG), self-rooted grafting involving one S. photeinocarpum seedling (SG), self-rooted grafting involving two S. photeinocarpum seedling developmental stages (DG), and grafting on wild potato rootstock (PG). Grafting did not induce genetic changes in S. photeinocarpum, and increased the shoot biomass and the amount of Cd extracted by the shoots of the first, second, and third generations of S. photeinocarpum (PG > DG > SG > UG). Additionally, enhanced superoxide dismutase, peroxidase, and catalase activities and increased soluble protein contents of the first post-grafting generation were observed for the DG and PG, whereas only enhanced superoxide dismutase and peroxidase activities were observed for the SG. Grafting increased the DNA methylation levels by inducing hypermethylation in the first post-grafting generation (PG > DG > SG > UG). Therefore, grafting can enhance the Cd accumulation (phytoremediation) ability of post-grafting generations of S. photeinocarpum by enhancing DNA methylation levels, especially when wild potato rootstock is used. [ABSTRACT FROM AUTHOR]

To study the effects of hyperaccumulator straw application on the growth and cadmium (Cd) accumulation of accumulator Perilla frutescens, four hyperaccumulator plant straws (Youngia erythrocarpa, Galinsoga parviflora, Gnaphalium affine and Crassocephalum crepidioides) were mulched on the surface of a Cd-contaminated soil (10 mg/kg) and P. frutescens seedlings were planted. The Y. erythrocarpa, G. affine and C. crepidioides straws increased P. frutescens root and shoot biomasses, and its chlorophyll a, carotenoid and total chlorophyll contents, whereas G. parviflora decreased or had no significant effect on these parameters. The G. affine and C. crepidioides straws enhanced the superoxide dismutase and catalase activities, and increased the Cd contents in roots and shoots of P. frutescens, whereas Y. erythrocarpa and G. parviflora straws had a smaller increasing effect. The Y. erythrocarpa, G. affine and C. crepidioides straws increased Cd extraction by P. frutescens shoots by 13.44%, 51.96% and 55.67%, respectively, compared with the control, whereas G. parviflora straw decreased it. Therefore, mulching with Y. erythrocarpa, G. affine and C. crepidioides straws could promote P. frutescens growth and enhance its phytoremediation ability for Cd-contaminated soil, with a better effect for G. affine and C. crepidioides straws than Y. erythrocarpa straw. [ABSTRACT FROM AUTHOR]

A pot experiment was conducted to study the effects of different rootstocks on the cadmium (Cd) accumulation characteristics of the post-grafting generations of Cd-hyperaccumulator Galinsoga parviflora plants. Five treatments, ungrafted and G. parviflora seedlings grafted on the rootstocks of Kalimeris indica, Senecio scandens, Conyza canadensis, and Artemisia sieversiana, were utilized. The four rootstock grafts decreased the shoot biomass of the G. parviflora post-grafting generation compared with ungrafted. The K. indica and S. scandens grafts increased the Cd concentration in shoots of the G. parviflora post-grafting generation by 15.06% and 14.40%, respectively, compared with ungrafted, while the C. canadensis and A. sieversiana grafts had no significant effects. K. indica grafts increased the amount of Cd extracted by shoots of the G. parviflora post-grafting generation by 10.59% compared with ungrafted, while the other treatments resulted in decreases. Compared with ungrafted, the different rootstocks had no significant effects on the photosynthetic pigment content of the G. parviflora post-grafting generation, and only C. canadensis grafts increased the superoxide dismutase activity level, while only K. indica grafts increased the peroxidase activity level. Therefore, the K. indica rootstock could increase the phytoremediation capability of G. parviflora post-grafted plants grown in Cd-contaminated soil. [ABSTRACT FROM AUTHOR]

To study whether grafting can reduce the heavy metal uptake of Cyphomandra betacea, C. betacea seedlings were grafted onto three different rootstocks (eggplant, Solanum nigrum, and tomato) and planted in cadmium (Cd)contaminated soil. Compared with ungrafted seedlings, S. nigrum rootstock increased the biomass of different organs of C. betacea seedlings, while eggplant and tomato rootstocks decreased it or had no significant effect. Chlorophyll a, chlorophyll b, and total chlorophyll contents of C. betacea seedlings were ranked as follows: S. nigrum rootstock > ungrafted > eggplant rootstock > tomato rootstock. The three rootstocks had no significant effects on the superoxide dismutase activity of C. betacea seedlings. Solanum nigrum rootstock enhanced the peroxidase and catalase activities and soluble protein content of C. betacea seedlings, while the other rootstocks reduced or had no significant influence on these parameters. The three rootstocks increased the Cd content of aboveground organs of C. betacea seedlings as follows: S. nigrum rootstock > eggplant rootstock > tomato rootstock > ungrafted. Grafting onto S. nigrum rootstock can therefore promote the growth of C. betacea; however, all rootstocks investigated in this study promote Cd uptake in C. betacea and thus cannot be used in Cd-contaminated areas. [ABSTRACT FROM AUTHOR]

The effects of mutual grafting on cadmium (Cd) accumulation in post-grafting generations of two Bidens pilosa ecotypes (farmland and mining) were studied in a pot experiment involving the following: ungrafted farmland ecotype (F-CK), the farmland ecotype as the rootstock (F-Rootstock), the farmland ecotype as the scion (F-Scion), ungrafted mining ecotype (M-CK), the mining ecotype as the rootstock (M-Rootstock), and the mining ecotype as the scion (M-Scion). The mutual grafting increased the shoot biomass and photosynthetic pigment contents (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid) of the post-grafting generations of both ecotypes, with F-Scion and M-Rootstock producing the highest values in their respective ecotypes. However, mutual grafting had no significant effect on the root and shoot Cd contents of the post-grafting generations. Additionally, mutual grafting increased the Cd extraction by the shoots of the post-grafting generations of farmland and mining ecotypes, with the F-Scion and M-Rootstock values 33.94% and 24.07% higher than those of F-CK and M-CK, respectively. Therefore, the mutual grafting of the two ecotypes promoted the growth and ability to extract Cd (phytoremediation ability) of post-grafting B. pilosa generations. Moreover, the farmland ecotype as scion and mining ecotype as rootstock was the best combination. [ABSTRACT FROM AUTHOR]

To enhance the phytoremediation ability of the heavy metal accumulator Perilla frutescens, melatonin (MT) was applied at different concentrations (0, 25, 50, 100, 150, and 200 μmol/L) to P. frutescens growing in cadmium (Cd) contaminated soil (10 mg/kg). The MT treatments increased the root and shoot biomasses of P. frutescens, with the maximum increase in the 150 μmol/L MT treatment (79.51% and 36.18% higher, respectively, than those of the control). The MT treatments also enhanced superoxide dismutase activity, peroxidase activity, and the soluble protein concentration of P. frutescens, and 100–200 μmol/L MT increased the chlorophyll a, chlorophyll b, and total chlorophyll concentrations in P. frutescens. The MT treatments increased the Cd concentrations in roots and shoots of P. frutescens in a dose-dependent manner. Different MT concentrations increased the Cd accumulation amounts of roots and shoots of P. frutescens, with the maxima accumulation amounts in the 150 μmol/L MT treatment (226.98% and 85.89% higher, respectively, than those of the control). These results show that MT can promote the growth and phytoremediation ability of P. frutescens growing in Cd-contaminated soil, and the optimum MT dose is 150 μmol/L. [ABSTRACT FROM AUTHOR]

In this experiment, four cadmium (Cd) hyperaccumulator species (Crassocephalum crepidioides, Galinsoga parviflora, Sigesbeckia orientalis, and Solanum nigrum) were intercropped with grape (Vitis vinifera) cuttings together in Cd-containated soil to study the effects of intercropping with the Cd-hyperaccumulator plants on growth and Cd accumulation of grape seedlings. Compared with the monoculture, intercropping with S. nigrum increased the biomass of grape seedlings, but intercropping with the other three hyperaccumulator species decreased the grape seedling biomass. Intercropping with S. nigrum increased chlorophyll a and total chlorophyll contents in leaves of grape seedlings compared with the monoculture, whereas intercropping with the other three hyperaccumulator species showed either a decrease or no effect. Intercropping with hyperaccumulator plants had no significant effects on chlorophyll b and carotenoid contents in leaves of grape seedlings compared with the monoculture. Compared with the monoculture, intercropping with C. crepidioides, G. parviflora, S. nigrum and S. orientalis significantly decreased Cd contents in shoots of grape seedlings by 78.7%, 12.7%, 29.8% and 26.5%, respectively. Therefore, intercropping with hyperaccumulator plants can decrease Cd accumulation in grape, and intercropping with S. nigrum can also promote grape seedling growth. [ABSTRACT FROM AUTHOR]

In this study, three cadmium (Cd) accumulator species (Conyza canadensis, Cardamine hirsuta, and Cerastium glomeratum) were co-cultured in Cd-contaminated soil in pots to study the effects of intercropping on co-remediation. Only C. canadensis intercropped with C. glomeratum, C. hirsuta intercropped with C. glomeratum, and three-species intercropping increased plant biomass compared with their respective monocultures. The treatments of C. canadensis intercropped with C. glomeratum and three-species intercropping increased the Cd contents in roots and shoots of C. canadensis, whereas the other intercropping treatments decreased or had no significant impact on Cd contents. As for Cd accumulation, the treatments of C. canadensis intercropped with C. glomeratum, C. hirsuta intercropped with C. glomeratum, and three-species intercropping increased Cd accumulation in a single plant compared with that of their respective monocultures, whereas other intercropping treatments decreased Cd accumulation in individual plants. Only the treatments of C. canadensis intercropped with C. glomeratum and C. hirsuta intercropped with C. glomeratum increased Cd accumulation in shoots of a single pot compared with that of their respective monocultures. Therefore, C. canadensis intercropped with C. glomeratum and C. hirsuta intercropped with C. glomeratum may improve the phytoremediation efficiency for Cd-contaminated soil. [ABSTRACT FROM AUTHOR]

The effects of uniconazole (S-3307) application on the growth and cadmium (Cd) accumulation of accumulator plantMalachium aquaticum(L.) Fries. were studied through a pot experiment. The application of S-3307 increased the biomass and photosynthetic pigment content ofM. aquaticumin Cd-contaminated soil, and also improved the superoxide dismutase (SOD) and peroxidase (POD) activities inM. aquaticum. Application of S-3307 increased Cd content in shoots and decreased Cd content in roots ofM. aquaticum, but the translocation factor (TF) ofM. aquaticumincreased with the increase of S-3307 concentration. For phytoextraction, the application of S-3307 increased Cd extractions by roots, shoots and whole plants ofM. aquaticum, and the maxima were obtained at 75 mg L−1S-3307, which increased by 22.07%, 37.79% and 29.07%, respectively, compared with their respective controls. Therefore, S-3307 can be used for enhancing the Cd extraction ability ofM. aquaticum, and 75 mg L−1S-3307 was the optimal dose. [ABSTRACT FROM AUTHOR]