Radish Biomass Research Articles

Swine wastewater co-exposed with veterinary antibiotics enhanced the antibiotic resistance of endophytes in radish (Raphanus sativus L.)

The widespread utilization of antibiotics in livestock has promoted the accumulation and diffusion of antibiotics and antibiotic resistance in agricultural soils and crops. Here we investigated the mechanisms of antibiotic uptake and accumulation in swine wastewater (SW)-treated radish (Raphanus sativus L.) and subsequent impacts on endophyte antibiotic resistance. Under SW treatments, exposure to 500 μg/L sulfamethazine (SMZ) and enrofloxacin (EFX) significantly affected radish biomass, with SMZ causing 63.0% increases and EFX causing 36.3% decreases relative to the untreated control. EFX uptake by radish were from 5 to 100-folds over SMZ. Passive diffusion through anion channel proteins on cell membranes was an important route for SMZ uptake, while both passive diffusion and energy-dependent processes contributed to the uptake of EFX. Bacterial community was time-dependent as a function of both antibiotics and SW, the bacterial alpha diversity in liquid solution co-treated with antibiotics and SW increased over time. The abundance of antibiotic resistance genes (ARGs) in the roots was positively correlated with ARGs in the Hoagland's solution under antibiotic-alone treatments. EFX co-exposure with SW enhanced the dissemination of ARGs from swine wastewater into plant roots, and significant correlations existed between ARGs and integrons in both Hoagland's solution and roots. These findings increased our understanding of the fate of antibiotics in crops and their subsequent impacts on antibiotic resistance of endophytic bacteria.

Influence of biochemical composition of above-ground biomass of oilseed radish on the expediency of its green manure application

Over a ten-year period, the volumes of formed ground biomass of oil radish and its biochemical composition were estimated for spring and summer plantings in terms of its green manure application. The formed leaf and stem mass of the oil radish variety Zhuravka was studied using official AOAC international analysis methods, liquid chromatography, methods of field evaluation of yield and weight and equivalent indicators. The effectiveness of green manure application was assessed by the method of multicriteria-decision support. Oil radish was confirmed to have a high adaptive potential at the maximum level of determination of bioproductivity, with an optimal moisture and temperature supply of up to 40%. The long-term average productive and biochemical portfolio of oil radish was identified as follows: 21.19 t/ha of leaf-stem ground mass with 62.3% soil cover 70 days after sowing, 2.8% nitrogen, 22.8% fibre, 0.6% phosphorus, 3.8% potassium, 16.6 μmol/g glucosinolates at the C/N ratio of 14.7, 83% plant-mass quality, and 48.1 mol/ha biofumigation potential based on glucosinolate aucumulation. The study confirmed the high potential of oilseed-radish adaptability to the regimes of unstable moisture of territories, finding interannual variation of the total bioproductivity and biochemical parameters of leaf-mass quality with the value of the variation coefficient ranging 23.6–31.2%, depending on the sowing date. The effectiveness of oilseed radish was also revealed by comparison with the similar interannual variation of hydrothermal conditions of vegetation (the amount of precipitation 48.2%, average daily temperature 27.5%, moisture coefficient 68.1%, and aridity index 58.9%). Oilseed radish was found to be agrobiologically and agrotechnologically feasibile to be used in the system of both spring and summer (intermediate) green manure technologies in grey loess soils under conditions of unstable moisture, as indicated by its bioproductivity and biochemical quality of leaf mass, as well as the results of the components of the multicriteria assessment of the plant as green manure, the value of normalised weight coefficients ranging 0.62–0.99

Glycine Betaine Induces Tolerance to Oxidative Stress in Cherry Radishes under High-Temperature Conditions

Cool-season plant growth and development are impacted by high temperatures. As a biostimulant, glycine betaine is responsible for inducing tolerance to both biotic and abiotic stressors. However, the mechanism by which glycine betaine protects cool-season crops against high-temperature stress is not clear. In the present study, under the conditions of high temperatures (35 °C/30 °C day/night), cherry radishes (Raphanus sativus var. radicula Pers.) (Brassicaceae) were cultured for 9, 18, and 27 days, and different concentrations (0, 0.067, 8.79, 11.72, 14.65, and 17.58 mg L−1) of glycine betaine were applied to investigate the influence of glycine betaine on cherry radish biomass, quality, net photosynthetic rate, chlorophyll content, antioxidant enzyme activity, and endogenous hormone content under high-temperature stress. The results showed that, under high-temperature conditions, cherry radishes grew best with the 17.58 mg L−1 glycine betaine treatment. At day 27, comparing the 17.58 mg L−1 glycine betaine treatment with 0 mg L−1 glycine betaine under high-temperature stress, the cherry radish biomass increased by 44.7%, while the soluble protein and vitamin C content increased by 14.4% and 21.6%, respectively, the net photosynthetic rate and chlorophyll a content increased by 7.8% and 44.1%, respectively, and the peroxidase and catalase levels increased by 81.0% and 146.3%, respectively. On day 9, the auxin, abscisic acid, and glycine betaine contents significantly increased by 67.4%, 6.8%, and 32.9%, respectively, in comparing the 17.58 mg L−1 glycine betaine treatment with 0 mg L−1 glycine betaine under high-temperature stress. Therefore, the application of 17.58 mg L−1 betaine to cherry radishes grown under high-temperature stress had positive effects. The appropriate concentration of glycine betaine can improve the resistance of cherry radish to high temperatures and maintain yield.

Photo-biological Effectiveness of PAR for Radish Plant Communities Irradiated Using an LED Source with an Adjustable Spectrum

The aim of the current study was to find the most effective spectral modes of irradiation of short-season plants (for example, radish) using a fluorescent LED irradiator with a variable spectrum. The research methodology was based on the species-specific response of plants to the spectral composition of light. Photo-biological experiments were carried out to find effective spectral composition of PAR for cultivating radish communities under stable and variable irradiation modes of electrical lighting. It was shown that under stable irradiation modes, the highest productivity of economically useful radish biomass had been achieved at spectral composition with a maximum of 60 % radiation in the (600–700) nm region in a variable spectral irradiation mode. The variable spectral irradiation mode turned out to be the most effective when the spectral composition with the dominance of red rays was changed to the spectral composition with the dominance of blue rays. There were no significant differences between the best production parameters for stable and variable modes of irradiation of radish plants, which indicates the expediency of choosing the stable spectral mode of irradiation of radish plants as a short-season crop under electrical illumination. The results obtained can be used to select spectral irradiation modes for short-season plants grown under electrical lighting in northern regions and in isolated rooms in various climatic zones using “City-farm” technologies.

Soil texture, fertilization, cover crop species and management affect nitrous oxide emissions from no-till cropland

Cover crops reduce nitrate leached, but effects on nitrous oxide (N2O) emissions are mixed. Cover crops can reduce N2O emissions by reducing levels of mineral nitrogen (N) and surface soil moisture during spring. Cover crops can also increase N2O emissions by adding organic substrates, releasing N during decomposition, or increasing summer soil water content. Winter-killed cover crops can increase soluble organic C and N during periods of typically low microbial activity. We hypothesized that planting a cover crop mix of radish (Raphanus sativus)-crimson clover (Trifolium incarnatum)-rye (Secale cereale) would increase direct N2O emissions relative to no cover crop, and result in lower direct and indirect N2O emissions than planting radish alone. We also hypothesized that extending the cover crop growing season, by planting earlier and killing later, would increase direct N2O emissions during winter, decrease direct N2O emissions during summer, and decrease indirect N2O emissions. To address these hypotheses, we conducted two field experiments (on sandy and silty soils) over four site-years. We measured cover crop biomass and N content, soil mineral N concentrations, soil moisture, green canopy cover, soil porewater nitrate, direct N2O emissions, and estimated indirect N2O emissions. Nitrous oxide emissions were ~ 7.8 times greater at the silty than the sandy sites due to greater soil moisture retention. Site-years with high radish biomass exhibited greater direct N2O emissions than sites with low radish biomass following winter-kill. Indirect N2O emissions were decreased ~7 % by planting cover crops and by ~70 % by planting cover crops early. Fertilizer induced emission peaks were 8.2 times greater than all previous N2O emissions combined at a silty site. Our results suggested that soil texture and fertilization played an important role in direct N2O emissions, while cover crop species, biomass, and timing played a more important role in NO3 leached, and thus, indirect N2O emissions.

Engineered biochar fabricated from waste biomass of radish leaves for the fluoride removal from aqueous medium

Engineered biochar fabricated from waste biomass of radish leaves for the fluoride removal from aqueous medium

Effects of intercropping on Se accumulation and growth of pakchoi, lettuce and radish

Selenium is one of the most basic trace elements in the human body. It is necessary to improve the selenium content in agricultural products through agricultural planting technology to ensure that human nutrition and health need selenium. Therefore, our research passed the effect of intercropping on the growth and selenium accumulation of pakchoi, lettuce and radish were studied through pot experiments to determine whether intercropping of the three crop species can improve their selenium accumulation ability. The results showed that intercropping increased the root and shoot biomass of pakchoi and radish compared with the monocultures, while the biomass of roots and shoots decreased in other intercropping combinations. Intercropping also affected the photosynthetic pigment content of the three crop species. Specifically, the photosynthetic pigments increased in pakchoi and decreased in radish after intercropping. Notably, intercropping the three crop species together increased the SOD (superoxide dismutase) activities of the three crops compared with the monocultures. Meanwhile, intercropping radish with lettuce significantly increased the activities of SOD and CAT (catalase) in radish. Intercropping also increased the soluble sugar content in pakchoi and soluble protein content of radish relative to the monocultures. Furthermore, intercropping decreased the selenium content and the bioconcentration factor of the roots of the three vegetable crops, but improved the shoot selenium content, the bioconcentration factor and the transport factor of Se in pakchoi and radish. In conclusion, intercropping combination of pakchoi and radish can improve selenium accumulation in the edible parts of the crops, which is significant for efficient production of selenium-enriched vegetables.

Responses of cherry radish to different types of microplastics in the presence of oxytetracycline

Croplands have become a hotspot for antibiotic and microplastic (MP) pollution. However, little is known regarding their combined effects on crops. In this study, the individual and combined effects of oxytetracycline (OTC) and three MPs (i.e., polypropylene (PP), polyamide (PA), and polyvinylchloride (PVC)) on cherry radish were investigated using pot experiments. Individually, OTC (50 mg kg−1), PA (2%, w/w), and PP (2%, w/w) induced negligible effects on cherry radish biomass and the root/shoot ratio. However, PVC (2%, w/w) significantly inhibited cherry radish growth; that is, its shoot and root fresh weight decreased by 46.2% and 81.1%, respectively. In the combined exposure groups, OTC alleviated the adverse effects of PVC on the cherry radish leaf number and shoot fresh weight. This was linked to that OTC increased the content of photosynthetic pigments. Superoxide dismutase activity in cherry radish roots was inhibited to different extents in all treatment groups except for the PA and PVC treatments. Malondialdehyde (MDA) content in cherry radish roots increased in all treatment groups, suggesting that both OTC and MPs caused oxidative damage to cherry radish root cells, therefore inhibiting cherry radish root growth. However, the presence of OTC non-significantly changed the effects of MPs on cherry radish roots. Irrespective of OTC presence, MPs induced a reduction in the root/shoot ratio of cherry radish, suggesting that the inhibitory effect of MPs on cherry radish roots was stronger than that on shoots. These findings contribute to the evaluation of the phytotoxicity of antibiotics and MPs in soil-vegetable systems.

Effect of microplastics on silty loam soil properties and radish growth

Abstract Microplastics (particles of plastics <5 mm) affect the physical, biological and hydrological properties of agricultural soil, as well as crop growth. We investigated the effect of the addition of three microplastics (high-density polyethylene (HDPE), polyvinyl chloride (PVC), and polystyrene (PS)) at a concentration of 5% (w/w) to a silty loam soil on selected soil properties and growth of radish (Raphanus sativus L. var. sativus). Changes in the soil properties and radish growth in three microplastic treatments were compared with the control. Soil properties (bulk density, hydraulic conductivity, sorptivity, water repellency) were estimated for each treatment at the beginning and at the end of the radish growing period (GP). The bulk density was significantly lower in the HDPE and PVC treatments compared to the control within the measurement at the beginning of the GP and in all microplastic treatments compared to the control at the end of the GP. The values of hydraulic conductivity and water sorptivity did not show significant differences between any treatments within the measurement at the beginning of GP, but they were significantly higher in the HDPE treatment compared to the control at the end of the GP. The growth of radish was characterized by the plant biomass and effective quantum yield of Photosystem II (Y (II)). We did not find a statistically significant difference in the total biomass of radish between any of the experimental treatments, maybe due to used concentration of microplastics. The mean value of Y (II) was significantly higher in all microplastic treatments compared to control only within the last measurement at the end of the GP. A statistically significant change of Y(II) in all microplastic treatments may indicate functional shift in soil properties; however, the measured values of the soil characteristics have not shown the significant changes (except for the bulk density values in all microplastic treatments and hydraulic conductivity together with sorptivity in HDPE treatment within the measurement at the end of GP).

CuO nanoparticles modify bioaccumulation of perfluorooctanoic acid in radish (Raphanus sativus L.)

ABSTRACT Research on combined phytotoxicity of perfluorooctanoic acid (PFOA) and nanoparticles is very important for the remediation of PFOA contaminated soil and further assessment for the potential of nano-enhanced phytoremediation. Here, joint effects of PFOA and CuO nanoparticles (nCuO) in plants were studied by exposing radish (Raphanus sativus L.) to PFOA (4 mg/kg) and nCuO (200 and 400 mg/kg) for 30 days, and measuring for contaminant accumulation, radish biomass, photosynthesis profiles and nutrient contents. Results showed that PFOA accumulated highly in radish organs but showed limited effects on radish biomass. nCuO could increase the transfer rate of PFOA from root to shoot and reduce PFOA accumulation in edible root part, but higher nCuO lead to decreased radish biomass. Reversely, PFOA alleviated the adverse effects of nCuO on leaf photosynthesis and root metabolism of vitamins and amino acids. These results provided basics for exploring possibility of nano-enhanced phytoremediation for PFOA soil pollution.

Detoxification difference of cadmium between the application of selenate and selenite in native cadmium-contaminated soil.

Cadmium (Cd) has strong mobility and could cause toxicity to plants, and selenium (Se) can effectively detoxify Cd stress. However, differences in the detoxification effects of different species and dosages of exogenous Se on Cd and its mechanism are still unclear. In this study, a pot experiment was conducted to determine the effects of different rates of selenite and selenate application on radish growth, the uptake and translocation of Cd, and the fractions of Cd transformation in native Cd-contaminated soil. Results indicated that the decrease in radish biomass in selenate treatment was significantly greater than that in selenite treatment at a high Se application rate (2.5 mg·kg-1) (p < 0.05). In contrast to selenite treatments, the application of selenate significantly increased the translocation of Cd from radish roots to shoots (p < 0.05). Cadmium concentration and its bioaccumulation factor in radish decreased gradually with increasing selenite application rates, while these values decreased at low Se rate (1 mg·kg-1) and increased at high Se rate for selenate treatment. Different Se application rates resulted in Cd fractions distributions to change in soil. Therefore, the application of selenite treatment had a greater detoxification effect on Cd in soil than that in selenate treatment, and the double toxic effect was observed between Se and Cd in high selenate treatment (2.5 mg·kg-1). Combined with human health risk asseeement, the application of 2.5 mg·kg-1 selenite could be a good approach for detoxification in native Cd-contaminated soil used in this study.

Yield Enhancement of Biostimulants, Vitamin B12, and CoQ10 Compared to Inorganic Fertilizer in Radish

Two pot experiments were conducted to evaluate the response of radish crops against different plant growth regulators, biostimulants, and leaf extracts at Yale University, USA. The first experiment examined the marginal effect of vitamin B12 when added to the Berlyn Laboratory’s proprietary biostimulant formula (GPB Core). Increasing concentrations of vitamin B12 were added, as investigated in groups SL (0 mg/L), SB1 (0.5 mg/L), SB2 (1.0 mg/L), and SB3 (1.5 mg/L). The addition of vitamin B12 conferred no significant incremental benefit over the GPB Core. However, the GPB Core formula (SL) increased fresh shoot biomass by 172.9%, dry shoot biomass by 136.4%, fresh root biomass by 64.7%, and dry root biomass by 29.1% over plant treated with inorganic fertilizer alone (p &lt; 0.01). The second experiment examined the combined marginal effect of vitamin B12 and coenzyme Q10 (CoQ10) when added to the GPB Core. The three experimental groups included the GPB Core plus inorganic fertilizer (S+); GPB Core, vitamin B12, CoQ10, and inorganic fertilizer (SBQ+); and GPB Core, vitamin B12, CoQ10, and no inorganic fertilizer (SBQ0). SBQ0 outperformed the inorganic fertilizer control in fresh shoot, dry shoot, fresh root, and dry root biomass by 190.3%, 127.1%, 128.5%, and 41.3%, respectively (p &lt; 0.01), indicating that inorganic fertilizer can be replaced by biostimulants while simultaneously increasing yield. Additionally, the differences between SBQ+ and SBQ0 in the biomass metrics were statistically insignificant, indicating that in the presence of biostimulants, inorganic fertilizers confer a slight marginal benefit. There was no evidence, however, that the addition of CoQ10 and vitamin B12 conferred benefits over S+. Overall, the application of biostimulants statistically significantly improves radish biomass. Both experiments indicate that under low stress conditions, biostimulants can replace inorganic fertilizer while simultaneously increasing yield.

THE ROLE OF SOIL MOISTURE REGIME IN ENHANCING BIOFUMIGATION EFFICACY AGAINST Meloidogyne Incognita (KOFOID ET WHITE) CHITW. ON TOMATO

Anaerobic soil disinfestation (ASD), through anaerobical decomposition of organic matter in the soil is currently recommended for the control of soil borne pests including nematodes. A greenhouse trial was conducted aimed to assess the efficacy of different soil moisture regimes i.e. field capacity (FC), saturation (SA) and flooding (FL) with and without forage radish (FR) biomass addition on suppressing of root knotnematodes (Meloidogyne incognita) in tomato plant growing soil. The trial was laid out as 7 treatments in 4 replicates in completely randomized design (CRD) pots. In addition to the six treatments of soil moisture regimes with and without fodder radish, vydate, as synthetic chemical nematicide was used as positive control treatment. However, FC soil moisture regime without fodder radish served as negative control treatment. pH, redox potential (Eh) and oxygen diffusion rate (ODR) were measured in the soil in one-week interval during 4 weeks of fodder radish decomposition period before tomato seedlings (cv. Elysa) transplanting. Root knot nematode population (Meloidogyne incognita), reproductive factor and galling index were determined 12weeks after transplanting. Tomato crop growth parameters including plant length, fresh and dry plant weights and fruit fresh weights were also recorded. Obtained data revealed that both pH, Eh and ODR in the soil during 4 weeks of fodder radish decomposition period dramatically declined under soil flooding with fodder radish green manure treatment. Flooding the soil with fodder radish significantly reduced nematode population, reproductive factor and galling index values. The treatment was comparable to that obtained with vydate application treatment and was finally reflected on improvement of all studied tomato growth attributes.

Effects of alginic acid on radish growth and osmotic adjustment substance content under cadmium stress

To study the effects of alginic acid on the growth of vegetables, a pot experiment was conducted to study the effects of spraying alginic acid at different dilution folds on the growth and osmotic adjustment substance content of radish under cadmium stress condition. The results showed that the biomass, leaf length and leaf width of radish with 600, 900, 1200 and 1500 dilution folds alginic acid were higher than those of the control, while the soluble protein content, relative conductivity and malondialdehyde content of the radish were lower than those of the control. When the dilution factor of alginic acid is 600 dilution folds, the biomass, leaf length and leaf width of radish’s roots, root tubers, leaves and edible parts all reach the maximum. Increased by 19.39%, 35.27%, 19.74%, 29.44%, 22.11% and 14.01% compared with the control, respectively; the soluble protein content, relative conductivity and MDA content of radish reached the lowest, which were 38.76%, 29.86% and 35.61% lower than the control, respectively. Sprayed diluted alginic acid can promote the growth of radish, and the best dilution factor is 600 dilution folds.

The effect of green manures on weediness of sugar beet

Thіs study aimed to investigate the effect of aplying post-harvest green manure on weediness of sugar beet crop rotation. Post-harvest green manure were grown under the conditions of the Scientific Research and Production Complex (NNVK) of Sumy National Agrarian University (Ukraine, Sumy oblast, Sumy region) after harvesting winter wheat from August to October 2000‒2004. After the plowing of it in the following 2001‒2006, a hybrid of sugar beet Umansky FM-97 was grown according to the technologies recommended for the local area. Potential weediness was determined by washing seeds from the soil on sieves at the beginning of the growing season and before harvesting sugar beets, and the actual weediness ‒ by quantitative-weight method before plowing the green manure and into the main stages of growth and development of sugar beets.&#x0D; The experimental plot had the least weediness under oilseed radish and the largest weediness under buckwheat as green manure. During growing seasons the radish oilseed formed good biomass and the number of weeds under its cover was noticeably reduced to 4.8 pieces/m2 and their mass ‒ to 21.8 g/m2. The findings obtained from statistic program showed the strongest correlation between the above-ground mass of radish and the number of weeds ‒ r = -0.55 and their weight ‒ r = -0.56. In the spring the amount of weed seeds under radish cover in the 0‒30 cm soil layer was reduced to 11.4 %, to 101 million units/ha, compared to the control without green manure. The impact factor of the effect of the radish biomass on the potential weediness was highest in all soil layers - within 70‒90 %. The biomass of radish decreased significantly the number of weeds in the sugar beet crops – by 39 to 19.2 pc/m2, and their weight ‒ by 23 % to 354 g/m2, compared to the control without green manure. Green radish oilseed mass had the greatest impact on reducing quantity of weeds – 67 % and their mass – 80 %. Radish cover provided the most significant reduction the potential weediness before harvesting sugar beets ‒ by 12 % in the 0-30 cm soil layer, compared to the control without green manure, where the amount of weed seeds was at 112 million units/ha. The inverse correlation of the radish biomass and the potential weediness at the time of sugar beet harvest was the closest ‒ r = -0.9.

Qualitative and Quantitative Yield in the Radish Crop Through the Utilization of rhizobacteria, Pseudomonas trivialis (L) and Earthworm, Eudrilus eugenae (L).

The specific density of earthworm in soil and the microorganisms in soil are correlated with each other. The fruitful interactions among soil microorganisms and the earthworms in soil serve to orchestrate the process of improvement in the crop yield. The Pseudomonas trivialis (L) is a deleterious rhizobacterial species. This rhizobacterial species is recognized for the production of Indole Acetic Acid (IAA) (the plant growth promoting hormone). The present attempt deals with use of Pseudomonas trivialis (L) rhizobacteria in different concentrations (CFU/ml) (0; 10 6 ; 10 7 and 10 8 ) for analysis of qualitative parameters of radish, Raphanus sativus (L) in presence and in absence of earthworms. With reference to biomass above ground and total Presence of rhizobacteria, Pseudomonas trivialis (L), earthworms were found enhancing growth of the radish, Rhaphanus sativus (L), the response of presence of earthworm was found significant over the control. The biomass of radish, Rhaphanus sativus (L) below ground was also found improved. The titers of inoculum of rhizobacteria, Pseudomonas trivialis (L) was found significant for Radish biomass promoting influence in vermin-field. The present attempt reporting rhizobacterial inoculum of about 10 8 CFU/ml as the most suitable for excellent biomass production of radish, Rhaphanus sativus (L). The system of “Vermi-field with rhizobacterial population” should be utilized efficiently radish crop yield.

Effects of Bacillus thuringiensis HC-2 Combined with Biochar on the Growth and Cd and Pb Accumulation of Radish in a Heavy Metal-Contaminated Farmland under Field Conditions.

The objective of this study was to explore the effect of heavy metal-resistant bacteria and biochar (BC) on reducing heavy metal accumulation in vegetables and the underlying mechanism. We tested Bacillus thuringiensis HC-2, BC, and BC+HC-2 for their ability to immobilize Cd and Pb in culture solution. We also studied the effects of these treatments on the dry weight and Cd and Pb uptake of radish in metal-contaminated soils under field conditions and the underlying mechanism. Treatment with HC-2, BC, and BC+HC-2 significantly reduced the water-soluble Cd (34–56%) and Pb (31–54%) concentrations and increased the pH and NH4+ concentration in solution compared with their vales in a control. These treatments significantly increased the dry weight of radish roots (18.4–22.8%) and leaves (37.8–39.9%) and decreased Cd (28–94%) and Pb (22–63%) content in the radish roots compared with the control. Treatment with HC-2, BC, and BC+HC-2 also significantly increased the pH, organic matter content, NH4+ content, and NH4+/NO3− ratio of rhizosphere soils, and decreased the DTPA-extractable Cd (37–58%) and Pb (26–42%) contents in rhizosphere soils of radish. Furthermore, BC+HC-2 had higher ability than the other two treatments to protect radish against Cd and Pb toxicity and increased radish biomass. Therefore, Bacillus thuringiensis HC-2 combined with biochar can ensure vegetable safety in situ for the bioremediation of heavy metal-polluted farmland.

Application of Melatonin-Enhanced Tolerance to High-Temperature Stress in Cherry Radish (Raphanus sativus L. var. radculus pers)

The growth and development of cold-season plants are susceptible to high temperature. Melatonin is a plant growth regulator with potential to improve plant tolerance to biological and abiotic stresses. In our study, cherry radish (Raphanus sativus L. var. radculus pers) was cultured at a high temperature (35 °C/30 °C day/night) and different concentrations (0, 11.6, 17.4, 29.0, 34.8 and 67.0 mg L−1) of melatonin were applied to these high-temperature stressed plants to its effects on biomass, quality, antioxidant enzyme activity, chlorophyll and endogenous hormone contents. The plants were grown under normal temperature (25 °C/20 °C) as control and high-temperature condition as HT-stress treatment. The results revealed that under high temperature with 29.0 mg L−1 melatonin treatment, cherry radish biomass was significantly increased by 12.9%, and the soluble protein and soluble solid were increased by 18.7 and 9.2%, respectively. The activity of antioxidant enzyme, ascorbate peroxidase and peroxidase were increased by 43.7 and 45.5%, respectively. The chlorophyll a and carotenoid contents were increased by 7.4 and 20.0% compared with the control at 27 days. The auxin and abscisic acid contents were significantly increased by 28.5 and 6.7% compared with HT at 9 days. Thus, application of optimal rate of melatonin had a positive effect on cherry radish growth under high-temperature stress.

Study on Selenium Accumulation Characteristics of Radish

In order to study the effects of different concentrations of selenium on the selenium accumulation characteristics of radish, we used the pot experiment to study effects of different selenium concentrations (0, 5, 10, 25, 50, 75, and 100 mg/kg) on the biomass and selenium content of radish. The results showed that selenium stress inhibited the biomass of radish and the higher the concentration of selenium and the stronger the inhibition of radish growth. In addition, the selenium content of radish increased with the increase of selenium concentration. Selenium content in radish roots, tubers and leaves were in the ranges of 21.71-346.64 mg/kg, 11.05-251.38 mg/kg, and 8.34-210.91 mg/kg respectively under the selenium stress. Compared with the selenium concentration of 0 mg/kg, all treatments significantly increased the tubers, leaves, shoots and whole plants of radish selenium accumulation. In all treatments, when the concentration of selenium was 25 mg/kg, the selenium accumulation of each part of radish reached the maximum and the selenium accumulation of radish in shoots and whole plants reached 111.96 μg/plant and 119.21 μg/plant respectively. In a word, radish has the strongest accumulation ability of selenium in soil when the concentration of selenium is 25 mg/kg, which can be considered as the best selenium concentration to increase the selenium content of radish.

Does Cover Crop Radish Supply Nitrogen to Corn?

Core Ideas Radish as a cover crop does not supply nitrogen to the subsequent corn crop. Radish can result in neutral, negative, and positive effects on corn yield. Radish can have substantial nitrogen uptake in the fall, but effects on spring soil nitrogen are variable. Radish (Raphanus sativus L.) grown as a cover crop can accumulate a significant amount of N when planted by late summer. However, it remains unclear if the N in the radish biomass can supply N to a subsequent corn (Zea mays L.) crop. The objectives of this project were to: (i) measure radish growth and N uptake, (ii) determine the effect of radish growth on plant available N content in soil throughout the subsequent growing season, and (iii) determine the effects of radish on corn yields and response to N fertilizer. This study was conducted across nine site‐years in northeastern and southern Wisconsin, with radish planted mid‐August following winter wheat (Triticum aestivum L.) harvest. The experimental design was a randomized complete block, split plot design, with cover crop as the whole plot factor and N rate as the split plot factor. Radish N uptake was ranged from 19.7 to 202 kg ha−1 across all site‐years. The effect of radish on in‐season plant available N (PAN) content differed across growing seasons, with radish both increasing and decreasing PAN. The ANOVA and regression analysis showed mostly neutral effects of radish on corn yield, although corn yield increases and decreases following radish occurred. This research supports the use of radish as a trap crop for fall N, as environmentally meaningful yields of N were contained in plant biomass, but also demonstrates that radish has no N fertilizer replacement value to the subsequent crop.