Artemisia argyi water extract promotes selenium uptake of peach seedlings.

Soil in most areas of the world is selenium (Se) deficient, which results a low Se content in agricultural products. To improve the fruit tree Se accumulation, the effects of different Artemisia argyi water extract concentrations (0, 100, 200, 300, and 400-fold dilutions) on the growth and Se accumulation of peach seedlings were studied by a pot experiment. A 300- and 400-fold dilution of A. argyi water extract increased the root and shoot biomass (dry weight), leaf chlorophyll a content, superoxide dismutase (SOD) activity, and peroxidase (POD) activity of peach seedlings, but decreased the leaf chlorophyll a/b. Different A. argyi water extract concentrations had no significant effects on peach leaf chlorophyll a content of peach seedlings, but increased the leaf carotenoid content, catalase (CAT) activity, and soluble protein content. Different A. argyi water extract concentrations increased the total Se, inorganic Se, and organic contents in roots and shoots of peach seedlings to some extent. Furthermore, A. argyi water extract concentration exhibited a linear relationship with the root and shoot total Se contents. Compared with the control, the 100-, 200-, 300-, and 400-fold dilutions of A. argyi water extract increased the shoot total Se content by 18.95%, 31.31%, 39.32%, and 51.59%, respectively. Different A. argyi water extract concentrations also increased the leaf Se metabolism-related enzyme activities of peach seedlings, including the activities of adenosine triphosphate sulfurase (ATPS), adenosine 5'-phosphosulfate reductase (APR), and serine acetyltransferase (SAT), as well as selenocysteine methyltransferase (SMT) to some extent. Moreover, correlation and grey relational analyses revealed the root total Se content, CAT activity, and ATPS activity to be closely associated with the total shoot Se content. Therefore, applying A. argyi water extract can thus promote the growth and Se uptake of peach seedlings, and the future study should focus on the application effects of Se uptake in peach fruits.

An amino acid fertilizer improves the emergent accumulator plant Nasturtium officinale R. Br. phytoremediation capability for cadmium-contaminated paddy soils.

Cadmium (Cd) contamination of paddy soil affects safe crop production. This study aimed to evaluate the effects of plant biostimulant amino acid fertilizer on the phytoremediation capability of an emergent accumulator plant Nasturtium officinale R. Br. for Cd-contaminated paddy soils. A pot study was carried out to study the effects of different concentrations of amino acid fertilizer on the Cd accumulation of N. officinale grown in Cd-contaminated paddy soil. The amino acid fertilizer increased the biomass of N. officinale. The amino acid fertilizer concentration exhibited a quadratic polynomial regression relationship with the root and shoot biomass. The fertilizer also increased the photosynthetic pigment (chlorophyll and carotenoid) contents, peroxidase (POD; EC 1.11.1.7) activity, and catalase (CAT; EC 1.11.1.6) activity of N. officinale, but decreased the soluble protein content and had no significant effect on the superoxide dismutase (SOD; EC 1.15.1.1) activity. Furthermore, the amino acid fertilizer increased the Cd content and Cd extraction of N. officinale. The shoot Cd extraction increased by 29.06%, 63.05%, 77.22%, and 17.40% at 1500-, 1200-, 900-, and 600-fold dilutions of the amino acid fertilizer, respectively, compared with the control. Moreover, the amino acid fertilizer promoted the Cd transport from the roots to shoots of N. officinale. The amino acid fertilizer concentration also exhibited a quadratic polynomial regression relationship with the root Cd content, shoot Cd content, root Cd extraction, and shoot Cd extraction, respectively. The correlation, grey relational, and path analyses revealed that the root biomass, shoot biomass, chlorophyll content, catalase activity, shoot Cd content, and root Cd extraction were closely associated with the shoot Cd extraction. Therefore, the amino acid fertilizer can promote Cd uptake and improve the phytoremediation capability of N. officinale to remediate Cd-contaminated paddy soils, and 900-fold dilution is the most suitable concentration.

Gibberellic acid promotes selenium accumulation in Cyphomandra betacea under selenium stress.

The selenium (Se) deficiency is threatening the human health, and the increase of Se content in food can prevent the Se deficiency of human body. To increase the Se content in fruit trees and alleviate the Se stress to fruit trees, the effects of gibberellic acid (GA) on the growth and Se accumulation in Cyphomandra betacea under Se stress were studied. Although GA increased the biomass of C. betacea, it did not significantly affect the root/shoot ratio. The root and shoot biomass had a quadratic polynomial regression relationship with the GA concentration. Furthermore, GA increased the photosynthetic pigment content, photosynthetic parameters, and antioxidant enzyme activity of C. betacea. GA also increased the Se content in C. betacea, peaking at 300 mg/L GA. For instance, GA (300 mg/L) increased the Se contents in roots and shoots of C. betacea by 70.31 and 22.02%, respectively, compared with the control. Moreover, the root Se and shoot Se contents had a quadratic polynomial regression relationship with the GA concentration. Correlation and gray relational analyses showed that the carotenoid, chlorophyll a, and chlorophyll b contents were closely related to the Se uptake in C. betacea under the GA application. These results show that GA (300 mg/L) can promote the growth and Se uptake of C. betacea under Se stress.

Effects of intercropping with Solanum photeinocarpum and its post-grafting generations on cadmium accumulation in loquat (Eriobotrya japonica).

Cadmium (Cd) contamination of orchard soils is a global problem that has been increasing. To decrease the Cd accumulation in fruits, intercropping the orchard crops with hyperaccumulator plants has been used for soil remediation. A pot and a field experiment were conducted to study the effects of intercropping the potential Cd-hyperaccumulator Solanum photeinocarpum and its post-grafting generations with loquat (Eriobotrya japonica) on the growth and Cd uptake of these two plant species. In the pot experiment, intercropping improved the biomass, Cd content, Cd extraction, and root-to-shoot Cd translocation in both species. Intercropping increased the DNA methylation levels, antioxidant enzyme activity, and soluble protein content of loquat seedlings. These results indicate that intercropping could improve the phytoremediation of S. photeinocarpum and its post-grafting generations and increase the Cd uptake in loquat seedlings. In the field experiment, intercropping increased the Cd contents in the old branches, while it decreased that in the young branches and fruits of loquat. These findings indicate that intercropping could increase the Cd uptake in old tissues but reduce the Cd uptake in young tissues and fruits of loquat. So, intercropping loquat with S. photeinocarpum and its post-grafting generations could be used in Cd-contaminated orchards.

Intercropping the potential Cd-hyperaccumulator Solanum photeinocarpum and its post-grafting generations with loquat mutually promoted the growth of two plant species, and also promoted the cadmium uptakes in S. photeinocarpum and old branches of loquat, while inhibited the Cd uptake in the loquat young tissues (young branches and fruits). These results are the new findings of the intercropping.

Comparison of the Fruit Volatile Profiles of Five Muscadine Grape Cultivars (Vitis rotundifolia Michx.) Using HS-SPME-GC/MS Combined With Multivariate Statistical Analysis.

Fruit aromas are composed of a complex mixture of volatile organic compounds, which are essential attributes associated with the overall flavor and consumer preference. Muscadine grape (MG; Vitis rotundifolia Michx.) is an aroma-dense fruit crop. However, there is very scarce information on its volatile profiles. In this study, the volatile constituents of five newly introduced MG cultivars, including Alachua, Carlos, Fry, Granny Val, and Noble, were profiled using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC/MS) combined with multivariate statistical analysis. A total of 44 compounds, including esters, aldehydes, alcohols, fatty acids, terpenes, ketones, and furan, were identified and relatively quantified. Principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) evidently discriminated against the five MG cultivars based on their volatile profiles. The specific volatiles that contributed the most to this discrimination were highlighted. Geraniol and cinnamyl alcohol were demonstrated to be essential for characterizing the Alachua MG cultivar, whereas ethyl trans-2-butenoate and propyl acetate were shown to be important compounds to characterize the Noble MG cultivar. The results further showed that 2-Ethyl-1-hexanol, (Z)-3-hexenal, and (E)-2-hexenol were closely related to Carlos, Fry, and Granny Val cultivars, respectively. This investigation is the first in-depth exploration of the volatile profiles of the aroma-dense muscadine grape, which is essential for future genetic or biotechnological improvements to attain a cultivar with the desired flavor.

Mowing enhances the phytoremediation ability of cadmium-contaminated soil in the post-grafting generations of potential cadmium-hyperaccumulator Solanum photeinocarpum.

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.

Preparation of Highly Swelling/Antibacterial Cross-Linked N-Maleoyl-Functional Chitosan/Polyethylene Oxide Nanofiber Meshes for Controlled Antibiotic Release.

Due to the cell affinity of chitosan (CS) and the hydrophilicity of polyethylene oxide (PEO), CS/PEO composited nanofiber meshes (NFMs) have been extensively used as wound healing dressings for skin tissue regeneration. Nonetheless, numerous innate drawbacks of the NFM system such as the use of toxic spinning solvents and cross-linkers, moderate water regain capacity, and lack of triggered release function significantly hampered their biomedical applications. In order to enhance their performances in promoting cell growth and preventing bacterial infection, highly swelling cross-linked N-maleoyl-functional chitosan (MCS)/PEO NFMs have been developed as the next-generation CS/PEO NFM system through an acid-free electrospinning process and a UV-irradiated cross-linked treatment without the use of aldehyde-containing cross-linkers. With the simultaneous introduction of ethylene oxide chains and disulfide bonds in the cross-linkages, this new NFM system displays enhanced swelling capability, antibacterial ability, triggered antibiotic release, and high biocompatibility. These biomedical merits enable the new NFM systems to be utilized as tissue scaffolds, especially for functional wound healing dressings.

Selenium accumulation characteristics of Cyphomandra betacea (Solanum betaceum) seedlings.

A pot experiment was conducted to study the selenium (Se) accumulation characteristics and the tolerance of Cyphomandra betacea (Solanum betaceum) seedlings under different soil Se concentrations. The 5 mg/kg soil Se concentration increased the C. betacea seedling biomass and photosynthetic pigment contents (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid), whereas the other soil Se concentrations (10, 25, and 50 mg/kg) inhibited seedling growth. Increases in the soil Se concentrations tended to decrease the superoxide dismutase activity and soluble protein content, but had the opposite effect on the peroxidase and catalase activities. The 5, 10, and 25 mg/kg soil Se concentrations decreased the DNA methylation levels of C. betacea seedlings because of an increase in demethylation patterns (versus 0 mg/kg), whereas the 50 mg/kg soil Se concentration increased the DNA methylation levels because of an increase in hypermethylation patterns (versus 0 mg/kg). Increases in the soil Se concentrations were accompanied by an increasing trend in the Se content of C. betacea seedlings. Moreover, the amount of Se extracted by the shoots was highest for the 25 mg/kg soil Se concentration. Therefore, C. betacea may be able to accumulate relatively large amounts of Se and its growth may be promoted in 5 mg/kg soil Se.

Effects of intercropping accumulator plants and applying their straw on the growth and cadmium accumulation of Brassica chinensis L.

Two pot experiments were conducted to study the effects of intercropping cadmium (Cd) accumulator plants (Stellaria media (L.) Villars, Cardamine hirsuta, Cerastium glomeratum Thuill, and Galium aparine L.) and applying their straw on the growth and Cd accumulation of Brassica chinensis L. Intercropping with four accumulator plants reduced the biomass, water content, and photosynthetic pigment content of B. chinensis compared with monoculture. Intercropping with accumulator plants increased the Cd content in the roots and shoot of B. chinensis, and the translocation factor (TF), root bioconcentration factor (root BCF), and shoot bioconcentration factor (Shoot BCF) increased. The soil pH decreased and the soil available Cd content increased by intercropping. Thus, intercropping with four accumulator plants can promote the Cd uptake of B. chinensis. The straw of four accumulator plants reduced the biomass, water content, and photosynthetic pigment content of B. chinensis compared with the control. The straw of S. media and C. hirsute increased the Cd content in the roots and shoots of B. chinensis, TF, root BCF, and shoot BCF. The straw of C. glomeratum and G. aparine decreased the Cd content in the roots and shoots of B. chinensis, TF, root BCF, and shoot BCF. The soil pH increased and the soil available Cd content decreased by application of straw. Thus, the straw of C. glomeratum and G. aparine can reduce the Cd uptake of B. chinensis.

Effects of reciprocal grafting on cadmium accumulation in post-grafting generations of two ecotypes of Solanum photeinocarpum.

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.

Effects of intercropping with two Solanum species on the growth and cadmium accumulation of Cyphomandra betacea seedlings.

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.

Exogenous melatonin promotes growth and sucrose metabolism of grape seedlings.

Melatonin (MT) has many important functions in plants. In this study, different concentrations of MT (0, 50, 100, 150, and 200 µmol/L) were sprayed on grape seedlings, and its effects on plant growth and sucrose metabolism were determined. The results show that there was a mutual influence and promotional relationship between growth and sugar metabolism in grape seedlings. The MT treatments promoted the development and growth of grape seedlings by increasing their biomass and promoting the photosynthetic performance of leaves. This resulted in increased nutrient absorption and a greater ability to compete for resources. The increase in photosynthesis resulted in greater sucrose production. The MT treatments increased the activities of enzymes related to sucrose metabolism, so that a large amount of sucrose was hydrolysed into glucose and fructose to meet the rapid growth requirements of grape seedlings. The increased total soluble sugars contents and increased activities of antioxidant enzymes resulted in greater resistance of grape seedlings, and greater adaptability to environmental changes. In general, MT treatments had beneficial effects on grape seedling growth, glucose metabolism, and resistance. Under these conditions, foliar spraying with MT at 150 µmol/L had the best effects.

Effects of carboxymethyl chitosan on the growth and nutrient uptake in Prunus davidiana seedlings.

To determine the effects of carboxymethyl chitosan on plant growth and nutrient uptake, Prunus davidiana seedlings were treated with various concentrations of carboxymethyl chitosan. The biomass, physiological characteristics, and nutrient uptake of the treated P. davidiana seedlings were then examined. Compared with the control seedlings, the carboxymethyl chitosan-treated seedlings had a higher biomass and a greater abundance of photosynthetic pigments (i.e., chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid), with the best concentration as 2 g/L carboxymethyl chitosan, which increased the shoot biomass and total chlorophyll content by 26.75% and 24.64%, respectively. Moreover, the application of carboxymethyl chitosan enhanced superoxide dismutase and catalase activities, increased the soluble protein content, and decreased the malondialdehyde and proline contents of the P. davidiana seedlings to some extent. Additionally, the carboxymethyl chitosan treatments decreased the total nitrogen content, but increased the total phosphorus and potassium contents in P. davidiana seedlings to some extent. The minimum of total nitrogen content and the maximum of total phosphorus and potassium contents in shoots of P. davidiana seedlings were the concentration of 2 g/L carboxymethyl chitosan, which was decreased by 12.96% and increased by 15.45% and 22.53%, respectively, compared with the control. Therefore, the application of a carboxymethyl chitosan solution may promote the growth, enhance the stress resistance, and alter the nutrient uptake of P. davidiana seedlings, especially at 2 g/L carboxymethyl chitosan.

Melatonin Alleviates Drought Stress by a Non-Enzymatic and Enzymatic Antioxidative System in Kiwifruit Seedlings.

Although melatonin was affirmed to alleviate drought stress in various plant species, the mechanism in kiwifruit remains to be elucidated. In this study, the transcriptomes of kiwifruit leaves under control (CK), DR (drought stress), and MTDR (drought plus melatonin) treatments were evaluated. After comparisons of the gene expression between DR and MTDR, the differentially expressed genes (DEGs) were screened. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated three significant pathways, which were mainly involved in the glutathione metabolism, ascorbate and aldarate metabolism, and carotenoid metabolism. Therefore, the content and metabolic gene expression level of ascorbic acid (AsA), glutathione, and carotenoid were higher in the MTDR treatment than that in others. Furthermore, the activity and mRNA expression level of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were also promoted in the MTDR group. Combined with these results of important secondary metabolites and protective enzymes measured in the seedlings in different treatments, it could be concluded that exogenous melatonin induced the ascorbic acid-glutathione (AsA-GSH) cycle, carotenoid biosynthesis, and protective enzyme system to improve seedling growth. Our results contribute to the development of a practical method for kiwifruit against drought stress.

Effects of reciprocal hybridization on cadmium accumulation in F1 hybrids of two Solanum photeinocarpum ecotypes.

In this study, farmland and mining ecotypes of Solanum photeinocarpum (a potential cadmium (Cd) hyperaccumulator plant) were reciprocally hybridized each other, and the Cd accumulation characteristics of the F1 hybrids were studied. In pot experiments, higher biomasses and Cd extraction abilities were found for two S. photeinocarpum F1 hybrids than for the parents, but the Cd contents in various organs were lower in the hybrids than the parents. However, the differences between the Cd contents in the two hybrids were not significant. The antioxidant enzyme (superoxide dismutase and peroxidase) activities were higher for the S. photeinocarpum F1 hybrids than the parents. Less DNA methylation was found in the hybrids than the parents because more demethylation occurred in the hybrids than the parents. The biomass, Cd content, and Cd extraction ability effects in field experiments were similar to the effects in the pot experiments. It was concluded that reciprocally hybridizing different S. photeinocarpum ecotypes improved the ability of S. photeinocarpum to be used to phytoremediate contaminated land.

Effects of different rootstocks on cadmium accumulation characteristics of the post-grafting generations of Galinsoga parviflora.

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.

Effects of mutual grafting on cadmium accumulation characteristics of first post-generations of Bidens pilosa L. and Galinsoga parviflora Cav.

We studied the effects of mutual grafting on cadmium (Cd) accumulation characteristics on the first post-generations of the Cd-hyperaccumulator plants Bidens pilosa L. and Galinsoga parviflora Cav. The seeds from scions and rootstocks of B. pilosa and G. parviflora were collected and planted in Cd-contaminated soil in pot and field experiments. In the pot experiment, rootstock treatment increased the shoot biomass of B. pilosa post-grafting generations, compared with ungrafted B. pilosa, but decreased the Cd content in shoots and Cd extraction by shoots of post-grafting generations; scion treatment decreased or had no significant effect. Mutual grafting resulted in no significant differences to the photosynthetic pigment contents in B. pilosa post-grafting generations. Compared with ungrafted G. parviflora, scion treatment increased the shoot biomass, photosynthetic pigment content, and Cd extraction by shoots of G. parviflora post-grafting generations, but rootstock treatment did not lead to significant differences. Mutual grafting resulted in no significant differences to the Cd contents in shoots of G. parviflora post-grafting generations. In the field experiment, only rootstock treatment increased the shoot biomass of B. pilosa post-grafting generations, and only scion treatment increased the shoot biomass and the Cd extraction by shoots of G. parviflora post-grafting generations. Therefore, mutual grafting of scions may enhance the phytoremediation ability of G. parviflora first post-grafting generations.

Effects of self-rooted grafting on growth and cadmium accumulation in post-grafting generations of soybean (Glycine max).

A study was performed to determine whether self-rooted grafting decreases cadmium (Cd) accumulation in post-grafting soybean (Glycine max (Linn.) Merrill) generations. Pot experiments were performed using ungrafted (UG) seedlings, self-rooted grafting from the same soybean seedling (SG), self-rooted grafting from two soybean seedlings at the same growth stage (TG), and self-rooted grafting from two soybean seedlings at different developmental stages (DG). Growth and Cd accumulation in three post-grafting soybean generations were assessed. In the SG treatment, only the second post-grafting generation had increased shoot biomass and only the first post-grafting generation shoots had decreased Cd contents. The seed Cd content, soluble protein content, and antioxidant enzyme activity were not significantly affected in three post-grafting generations. In the TG and DG treatments, shoot biomass, soluble protein content, and antioxidant enzyme activities were increased, and the shoot and seed Cd contents were decreased in three post-grafting generations. The seed Cd contents in the first, second, and third post-grafting generations were 15.00%, 9.46%, and 12.44%, respectively, lower in the TG than UG treatments. The seed Cd contents in the first, second, and third post-grafting generations were 32.73%, 27.03%, and 32.22%, respectively, lower in the DG than UG treatments. Different grafting methods promoted growth and decreased Cd accumulation to different degrees in three post-grafting generations. Grafting seedlings at different developmental stages had the strongest effects.

Self-rooted grafting influences the growth and cadmium accumulation characteristics in the post generation of Cosmos sulphureus.

To determine whether self-rooted grafting increases the cadmium (Cd) accumulation in post generations of hyperaccumulator or accumulator plants, a pot experiment was conducted to study the effects of self-rooted grafting on growth and Cd accumulation in the post generation of the accumulator plant Cosmos sulphureus. Four treatments were applied in the experiment with soil Cd concentration of 5 mg kg-1: ungrafted (UG), self-rooted grafting of the same C. sulphureus seedling (SG), self-rooted grafting of two C. sulphureus seedlings at the same growth stage (TG), and self-rooted grafting of two C. sulphureus seedlings at different developmental stages (DG). Compared with those of UG plants, the SG, TG, and DG treatments increased the root, stem, leaf, and shoot biomasses of plants in the post-grafting generation, consistent with the rank order DG > TG > SG > UG. The SG, TG, and DG treatments decreased the Cd contents in different organs of the post-grafting generation compared with those of UG plants. Only DG increased Cd extraction by the shoots in the post-grafting generation, which was increased by 6.28% compared with that of the UG treatment. In addition, SG, TG, and DG increased the photosynthetic pigment contents and enhanced antioxidant enzyme activities in the post-grafting generation compared with those of the UG treatment. Thus, self-rooted grafting promoted growth of C. sulphureus plants in the post generation. The DG treatment increased Cd extraction by C. sulphureus plants in the post-grafting generation, which may be exploited for phytoremediation of urban Cd-contaminated soil.