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Improvement of selenium (Se) uptake in fruit tree can improve the source of food Se for humans. In this study, the effect of various abscisic acid (ABA) concentrations on the Se uptake in Cyphomandra betacea Sendt. (Solanum betaceum Cav.) seedlings was studied under Se stress. Only the concentration of 20 μmol/L ABA promoted the growth of C. betacea seedlings by increasing the biomass and regulating the resistance physiology under Se stress. ABA also increased the Se content in C. betacea seedlings under Se stress. The concentration of ABA at 20 μmol/L got the maximum root Se and shoot Se contents, which increased by 76.64% and 55.83%, respectively, compared with the control. Correlation and grey relational analyses showed that the peroxidase activity and proline content had the first two closest relationship with the shoot Se content. This study shows that ABA can promote the Se uptake in C. betacea under Se stress, and the concentration of 20 μmol/L ABA is the optimum for Se uptake and growth of C. betacea. Under selenium (Se) stress, abscisic acid (ABA) promotes the Se uptake in Cyphomandra betacea Sendt. (Solanum betaceum Cav.) seedlings, but only the concentration of 20 μmol/L ABA promotes the growth of C. betacea seedlings. The shoot Se content is most closely correlated with the peroxidase activity and proline content. This study shows that ABA can promote the Se uptake in C. betacea under Se stress [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]

Melatonin (MT) is a signaling molecule that is widely present in plants and can help them resist abiotic stresses. In this study, the effects of different concentrations of exogenous MT on the growth and development of lettuce (Lactuca sativa) under cadmium stress (50 μmol/L) were investigated. Based on their Cd accumulation differences, the "Hong Feng" and "Luo Ma" lettuce cultivars were selected as research materials. The results showed that different concentrations of MT could promote the growth of lettuce under 50 μmol/L cadmium stress. The application of exogenous melatonin can significantly increase the plant height, biomass, chlorophyll, soluble protein and soluble sugar content of lettuce, and increase the net photosynthetic rate. MT could also reduce the malondialdehyde content in lettuce under cadmium stress and increase the activities of superoxide dismutase, peroxidase, and catalase activities. After treatment with different concentrations of MT, the Cd content in the shoots of both cultivars significantly decreased; in contrast, the Cd content in the roots was significantly increased, which limited the transport of Cd from underground to the shoots. In addition, both Cd stress and exogenous MT induced the synthesis of endogenous MT, and 50 μmol/L MT treatment most effectively induced this response. In conclusion, this study demonstrated that MT could alleviate the negative effects of Cd stress on lettuce with different Cd accumulation differences in terms of physiological indicators. Therefore, it provides a certain reference for the potential of MT to be applied to crops threatened by heavy metals. [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]

An 8 week feeding trial was carried out to investigate the effects of dietary nucleotides on growth performance, intestinal morphology, immune response and disease resistance of juvenile largemouth bass, Micropterus salmoides. Five grades of dietary nucleotide levels were designed as 0, 0.2, 0.4, 0.8 and 1.2 g kg−1, respectively. Each group had 3 replicates, with 40 fish in each replicate. After the feeding experiment, 15 fish from each tank were infected with Aeromonas hydrophila for 14 days. The results indicated that fish fed the diets containing 0.4, 0.8 and 1.2 g kg−1 nucleotides had higher growth performance and feed utilization than those fed the control diet. Nonetheless, there were no significant differences in survival between all the groups, although fish fed the diets with all‐level nucleotides obtained higher survival than those fed the control diet. Dietary nucleotides significantly affected the superoxide dismutase, acid phosphatase and catalase activities in serum but not the malondialdehyde content. Fish fed the 0.4 g kg−1 nucleotide diets had the highest fold height, enterocyte height and muscular layer thickness significantly. The average mortality of largemouth bass infected with A. hydrophila was significantly influenced by dietary nucleotides. The mortality was significantly higher in the control group (91.11%) and 0.02% nucleotide group (73.11%) followed by the other groups and lowest in the 0.8 g kg−1 nucleotide group. In summary, dietary 0.4–0.8 g kg−1 nucleotides promoted growth performance, enhanced immunity and improved intestinal morphology and disease resistance of largemouth bass. [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]

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]

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]

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]

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]

AbstractIntercropping can increase the utilization rate of light and water and can also improve plant growth. The objective of this study was to investigate the growth and selenium (Se) content in seedlings of three genotypes of cherry tomato under intercropping while applying Se. The pot experiment was conducted in a greenhouse. The monoculture of red, yellow and purple cherry tomato; among the three genotypes of cherry tomatoes, intercropping of two genotypes with each other, at the same time intercropping of three genotypes. These results show that the biomass increased under intercropping compared with monoculture. The chlorophyll b content of purple cherry tomato increased in different intercropping combinations. Furthermore, the net photosynthetic rate, stomatal conductance, and transpiration rate of purple were increased by intercropping with red and purple cherry tomatoes. The soluble protein and soluble sugar contents in yellow and purple cherry tomato increased by 49.13% and 8.37%, respectively, under mutual intercropping. Similarly, soluble sugar increased in purple cherry tomato by intercropping with yellow and red. The activities of superoxide and peroxidase in red and yellow cherry tomato seedlings were higher in all intercropping combinations than in monoculture, whereas free proline content and relative conductivity in all cherry tomatoes decreased. The Se content of roots, stem, and leaves in seedlings increased with intercropping. Therefore, intercropping can improve the growth and Se content of cherry tomatoes, and the combination of red, yellow and purple is better, which can be used to cultivate strong seedlings. [ABSTRACT FROM AUTHOR]

Mulching with plant straws on cadmium (Cd) contaminated soil can reduce Cd accumulation in crop plants. In this pot experiment, Cd‐contaminated soil was mulched with the straw of rice, wheat, rape, or broad bean, and their effects on the growth and Cd accumulation of Cyphomandra betacea seedlings were studied. Mulching with the straw of rice or broad bean increased the root, stem, leaf, and shoot biomasses of C. betacea seedlings, and increased the chlorophyll contents in leaves of C. betacea seedlings, whereas mulching with the straw of wheat or rape decreased this growth and photosynthetic pigment parameters. The Cd contents in the roots, stems, leaves, and shoots of C. betacea seedlings decreased in response to mulching with rice straw by 32.79%, 19.40%, 14.04%, and 14.86%, respectively, and decreased following mulching with rape straw by 12.27%, 18.22%, 6.89%, and 9.13%, respectively, compared with those of the control. Mulching with the straw of wheat or broad bean increased the Cd contents in C. betacea seedlings. Therefore, rice straw promoted the growth of C. betacea and significantly reduced the Cd uptake by C. betacea, which was beneficial for safe production of C. betacea in Cd‐contaminated orchards. © 2019 American Institute of Chemical Engineers Environ Prog, 38: e13229, 2019 [ABSTRACT FROM AUTHOR]

To determine whether the melatonin (MT) could reduce cadmium (Cd) accumulation in Cyphomandra betacea seedlings, different concentrations of MT were added to the nutrient solution and soil to study its effects on the growth and Cd characteristics of C. betacea seedlings. Fifty micromoles per liter (μmol/kg) of MT increased the biomass of C. betacea seedlings, but 100-200 μmol/L (μmol/kg) MT decreased seedling biomass in both the nutrient solution and soil cultivation experiments. The photosynthetic pigment contents showed no significant changes compared with the control when the MT dose was 150 μmol/L (μmol/kg) or less, while 200 μmol/L (μmol/kg) MT decreased the photosynthetic pigment contents. Low levels of MT improved the antioxidant enzyme activities of C. betacea seedlings, whereas high MT levels reduced them. MT increased the Cd contents in different organs of C. betacea seedlings in the nutrient solution cultivation experiment, but only 50 μmol/kg MT increased the Cd contents in stems, leaves, and shoots of C. betacea seedlings in the soil cultivation experiment. Therefore, only low levels of MT can promote the growth of C. betacea seedlings, and MT is not suitable for reducing Cd accumulation in C. betacea seedlings. [ABSTRACT FROM AUTHOR]

Chinese kale sprouts have garnered attention owing to its rich health-promoting compounds. This study aimed to investigate the effects of different light qualities (white, blue, and red light) and melatonin (100 μmol L−1), both individually and in combination, on the growth and accumulation of health-promoting compounds in Chinese kale sprouts. Red light positively influenced sprout growth (compared with white light, plant height and fresh weight increased by 16.67 % and 4.87 %, respectively), and the red light + melatonin treatment further enhanced growth (compared with single red light, the plant height and fresh weight increased by 14.97 % and 12.29 %, respectively), while increasing glucosinolate accumulation through the up-regulation of glucosinolate biosynthetic genes (UGT74B1 , CYP83B1 , SOT18 and IGMT1). Conversely, blue light inhibited sprout growth, elevated the expression levels of PAL , CHS , CHI , GGP , and PAX , improved antioxidant levels, and accelerated the accumulation of aliphatic glucosinolates, reducing indolic glucosinolates. The blue light + melatonin treatment promoted the accumulation of sprout biomass and anthocyanins (11.91 % and 13.33 % higher than that of single blue light). The study unveiled various pathways influencing plant growth, development, and secondary metabolite accumulation, including plant circadian rhythms, ascorbate and aldarate metabolism, phenylpropanoid biosynthesis, and glucosinolate biosynthesis. • The combination of light quality and melatonin increases biomass. • The combination of blue light and melatonin increase the content of anthocyanins. • Blue light increases the content of aliphatic glucosinolates. • The combination of red light and melatonin increased the content of the glucosinolates. [ABSTRACT FROM AUTHOR]

• AMF inoculation positively impacts Se accumulation and translocation in celery. • Low Se (≤10 mg kg−1) promotes growth, high concentrations inhibit it. • AMF enhances Se uptake, improves shoot height, root weight. • +AMF with 10 mg kg−1 Se4+ produces Se-rich celery, addressing deficiencies. Celery (Apium graveolens L.) has a strong capacity to enrich selenium (Se) and is a good system for research on Se enrichment in vegetables. Arbuscular mycorrhizal fungi (AMF) are commonly used plant symbionts that affect plant growth and their effectiveness is plant species specific. However, there is little research on the effects of AMF inoculation on the accumulation and translocation of Se in celery. The treatments in this study included inoculation with AMF (+AMF) and the application of different types and concentrations of exogenous Se. We evaluated the growth, root mycorrhizal colonization, photosynthetic pigment content, ascorbate-glutathione cycle (ASA-GSH cycle), the accumulation and translocation of Se and the combination of AMF + Se compared with an untreated control. The application of low concentrations of Se (≤10 mg kg−1) stimulated celery growth, while high concentrations (>20 mg kg−1) had the opposite effect. The inhibition of celery growth was more severe with Se6+ than Se4+ when applied at the same concentration. The accumulation of Se improved in all the organs of celery as the supply increased. AMF had a significant positive effect on the accumulation and translocation of Se. In addition, +AMF significantly increased the shoot height and root fresh weight of celery and reduced the inhibitory effect of Se on growth. However, +AMF had slight effects on the levels of photosynthetic pigments and the ASA-GSH cycle. +AMF combined with 10 mg kg−1 sodium selenite (Se4+) is an effective way to produce Se-rich celery. [ABSTRACT FROM AUTHOR]

• Melatonin promoted growth of peach. • Melatonin increased iron content in peach. • Melatonin increased chemical form of iron content that can be absorbed by plants. Iron deficiency leads to stunted growth in fruit trees and reduces the yield and quality of fruits. To increase the uptake of iron in fruit trees and provide a reference to control iron deficiency, the effects of different concentrations of melatonin (MT) on iron uptake in peach (Prunus persica) were studied by a pot experiment. Concentrations of 0, 50, 100, 150, and 200 µM MT were used in this experiment. MT increased the biomass of peach. Concentrations of 100, 150, and 200 µM MT increased the contents of total and active iron in peach. Concentration of 150 µM MT got the maxmiums of total iron contents in stems and leaves, which increased by 28.79% and 36.11%, respectively, compared with the control. Correspondingly, concentrations of 100 and 150 µM MT upregulated the genes related to iron absorption, including the ferric reduction oxidase 7 (FRO7), vacuolar iron transporter 1 (VIT1), and ferric reduction oxidase 4 (FRO4), while downregulating the vacuole genes vacuolar iron transporter homolog 4 (VITH4) and natural resistance-associated macrophage protein 3 (NRAMP3) that are related to vacuolar iron transport. The concentrations of absorbable iron forms, including the water soluble iron, adsorbed iron, carbonate and strongly adsorbed iron, and manganese oxide bound iron, in the soil increased, and the soil pH value decreased following the addition of 100, 150, and 200 µM MT. A correlation analysis showed that the contents of total and active iron in peach correlated with the biomass, soil pH value, absorbable soil iron forms, and level of expression of the iron absorption related genes. These observations indicate that treated with 100–200 µM MT could promote the iron uptake and accumulation in peach by regulating the physiological metabolism related to iron. [ABSTRACT FROM AUTHOR]