Helianthus Annuus Research Articles

A novel strategy to develop powdery mildew resistant phenotypes and diagnose reaction to Golovinomyces latisporus in sunflower (Helianthus annuus L.)

Among the various biotic stresses limiting sunflower productivity, powdery mildew incited by Golovinomyces latisporus has become a serious problem in the tropical regions. Reliable source of resistance has been identified in the diploid annual wild species Helianthus praecox (PRA-1823). Interspecific cross of cultivated sunflower (Acc. PS-2023) with PRA-1823 was advanced to develop interspecific recombinant inbred lines (IRILs) with distinct phenotypic reaction to the pathogen. The IRILs with similar morphology were subjected to molecular analysis by adopting the bulk pooling analysis (BPA) wherein DNA of eight each of susceptible and resistant IRILs were pooled to constitute the respective bulks. Fourteen sunflower specific SSR markers that showed polymorphism between the susceptible and resistant bulk IRILs, discriminated the powdery mildew resistant and susceptible samples as well. The primer ORS 485 was dominant and showed amplification only in the susceptible bulks and accessions and hence, it was converted to a multiplex reaction with actin to overrule the possibility of PCR failure. These 14 primers were successfully validated on IRIL populations and individual plants, a set of 40 breeding lines and 205 germplasm accessions with high susceptibility to the pathogen, 11 Helianthus species and three previously reported sources of resistance to powdery mildew (PM-81, IR-6, TX-16 R). This constitutes the first successful attempt at development of a diagnostic molecular marker set for distinguishing the powdery mildew resistant and susceptible genotypes in sunflower.

Transcriptome analysis suggests the role of expansin genes in the improved germination of sunflower (Helianthus annuus L.) seeds after hydropriming

AbstractSunflower (Helianthus annuus L.) is widely utilized for seed oil production. Priming seeds prior to sowing is a technique used to enhance the germination rate and uniformity of seedling growth. Priming times of 6 and 18 h were selected to be the optimal and extended durations, respectively. Three biological replicates per treatment were used for next‐generation sequencing via the Illumina platform. In this study, priming conditions decreased the time to 50% radicle emergence, implying earlier and more uniform germination without affecting the final germination percentage. Transcriptome analysis identified 6171 differentially expressed genes (DEGs) for 0–6 h, 7241 DEGs for 0–18 h, and 1527 DEGs for 6–18 h. The number of expressed DEGs during the early hours of priming exceeded those identified during the extended priming time, suggesting more metabolic processes were taking place in the earlier priming period. Noteworthy DEGs are related to stress responses, the biosynthesis of metabolites, and the activation of antioxidants and phytohormones. Moreover, these DEGs were significantly enriched in translation, metabolic processes, and biosynthesis for the priming times of 0–6 h and 0–18 h, whereas anaerobic respiration, detection of hypoxia, and lipid transport were differentially expressed between 6 and 18 h. Furthermore, expansin genes, namely, EXPA1, EXPA9, EXPA15, EXLA3, and EXP/Lol pI 3B GAG‐pre‐integrase domain, were significantly expressed. These expansins are cell wall‐loosening proteins that are involved in the processes of physiological development in higher plants, including seed germination. The data obtained in this study contribute toward deciphering the molecular mechanisms associated with seed priming in sunflower seeds.

In Vitro Fossilization for High Spatial Resolution Quantification of Elements in Plant-Tissue Using LA-ICP-TOFMS.

Laser ablation in combination with an inductively coupled plasma time-of-flight mass spectrometer (LA-ICP-TOFMS) is an upcoming method for rapid quantitative element mapping of various samples. While widespread in geological applications, quantification of elements in biotissues remains challenging. In this study, a proof-of-concept sample preparation method is presented in which plant-tissues are fossilized in order to solidify the complex biotissue matrix into a mineral-like matrix. This process enables quantification of elements by using silicone as an internal standard for normalization while also providing consistent ablation processes similar to minerals to reduce image blurring. Furthermore, it allows us to generate a quantitative image of the element composition at high spatial resolution. The feasibility of the approach is demonstrated on leaves of sunflowers (Helianthus annuus), soy beans (Glycine max), and corn (Zea mays) as representatives for common crops, which were grown on both nonspiked and cadmium-spiked agricultural soil. The quantitative results achieved during imaging were validated with digestion of whole leaves followed by ICP-OES analysis. LA-ICP-TOFMS element mapping of conventionally dried samples can provide misleading trends due to the irregular ablation behavior of biotissue because high signals caused by high ablation rates are falsely interpreted as enrichment of elements. Fossilization provides the opportunity to correct such phenomena by standardization with Si as an internal standard. The method demonstrated here allows for quantitative image acquisition without time-consuming sample preparation steps by using comparatively safe chemicals. The diversity of tested samples suggests that this sample preparation method is well-suited to achieve reproducible and quantitative element maps of various plant samples.

Identifying Physiological Traits Associated with High Temperature Tolerance in Sunflower (Helianthus annuus L.) Genotypes

The objective of the study is to identify the physiological traits associated with seed yield in sunflower. An experiment was conducted at ICAR-Indian Institute of Oilseeds Research, Narkhoda Farm, Rajendranagar, Telangana during rabi (Jan-May) 2019 and 2020 to find out the response of Sunflower genotypes to high temperature (HT) stress. Here, 47 genotypes were screened in the first year and 14 genotypes were identified which are evaluated in the second year under timely (control, S1) and delayed (HT stress, S2) sowings. These traits in the two years are correlated with seed yields (SY) which were differed under S1 and S2. The per se performance indicated that the expression of most traits was reduced under S2 except canopy temperature in 2019. The genotype AKSF 6-3B with the highest SY were characterized by chlorophyll content, maximum quantum efficiency, relative water content, pollen viability, leaf area index, photosynthetic rate and transpiration at vegetative stage under high temperature. The diverse genotypes identified with promising traits can be used in breeding programs to develop new varieties.

Characterization and use of activated carbon synthesized from sunflower seed shell in the removal of Pb(II), Cd(II), and Cr(III) ions from aqueous solution.

In this work, carbon-based nanomaterials such as active carbon which is prepared from common sunflower (Helianthus annuus) seed shell, and the characterization of the activated carbon NPs were studied using FTIR (Fourier transform infrared spectroscopy), XRD, SEM, EDS, and DTA techniques. Activated carbon NPs have been used in the adsorption of Pb(II), Cd(II), and Cr(III) ions from the aqueous phase. The results showed the highest adsorption efficiency was 99.9%, 92.45%, and 98% for Pb(II), Cd(II), and Cr(III) ions respectively at a temperature of 25 °C, pH = 7-9, and a time of 60 and 180 min, in addition to the accordance of the adsorption models for activated carbon with the Freundlich isotherm model at the value of R2 (0.9976, 0.9756, and 0.9907) and Langmuir isotherm model (0.966, 0.999, and 0.9873) of the Pb(II), Cd(II), and Cr(III) ions, respectively. We conclude the possibility of using activated carbon to have an extremely high sorption capacity across the conditions tested, with the highest adsorption efficiency having been >99% for Pb(II), Cd(II), and Cr(III) ions within the pH range 7-9 and a contact time of 60 to 180 min.

Synergistic application of Pseudomonas strains and compost mitigates lead (Pb) stress in sunflower (Helianthus annuus L.) via improved nutrient uptake, antioxidant defense and physiology

Lead (Pb) is one of the most dreadful non-essential elements whose toxicity has been well reported worldwide due to its interference with the major plant functions and its overall yield. Bioremediation techniques comprising the application of beneficial microorganisms have gained attention in recent times owing to their ecofriendly nature. Addition of organic matter to soil has been reported to stimulate microbial activities. Compost application improves soil structure and binds toxic contaminants due to its larger surface area and presence of functional groups. Furthermore, it stimulates soil microbial activities by acting as C-source. So, in current study, we investigated the individual and synergistic potential of two lead (Pb)-tolerant Pseudomonas strains alongwith compost (1% w/w) in sustaining sunflower growth under Pb contaminated soil conditions. Lead chloride (PbCl2) salt was used for raising desired Pb concentration (500 mg kg−1). Results revealed that Pb stress drastically affected all the measured attributes of sunflower plant, however joint application of rhizobacteria and compost counteracted these adverse effects. Among them, co-application of str-1 and compost proved to be significantly better than str-2, as its inoculation significantly improved shoot and root lengths (64 and 76%), leaf area and leaves plant−1 (95 and 166%), 100-achene weight (200%), no. of flowers plant−1 (138%), chl ‘a’, ‘b’ and carotenoid (86, 159 and 33%) contents in sunflower as compared to control treatments. Furthermore, inoculation of Pseudomonas fluorescens along with compost increased the NPK in achene (139, 200 and 165%), flavonoid and phenolic contents (258 and 185%) along with transpiration and photosynthetic rates (54 and 72%) in leaves as compared to control treatment under Pb contamination. In addition, Pb entry to roots, shoots and achene were significantly suppressed under by 87, 90 and 91% respectively due to integrated application of compost and str-1 as evident by maximum Pb-immobilization efficiency (97%) obtained in this treatment. Similarly, bioconcentration factors for roots, shoots and achene were found to be 0.58, 0.18 and 0.0055 with associated translocation factor (0.30), which also revealed phytostabilization of Pb under combined application of PGPR and compost. Since, phytoremediation of heavy metals under current scenario of increasing global population is inevitable, results of the current study concluded that tolerant PGPR species along with organic amendments such as compost can inhibit Pb uptake by sunflower and confer Pb tolerance via improved nutrient uptake, physiology, antioxidative defense and gas exchange.

Exploring the anti-gout potential of sunflower receptacles alkaloids: A computational and pharmacological analysis

Gout, a painful condition marked by elevated uric acid levels often linked to the diet's high purine and alcohol content, finds a potential treatment target in xanthine oxidase (XO), a crucial enzyme for uric acid production. This study explores the therapeutic properties of alkaloids extracted from sunflower (Helianthus annuus L.) receptacles against gout. By leveraging computational chemistry and introducing a novel R-based clustering algorithm, “TriDimensional Hierarchical Fingerprint Clustering with Tanimoto Representative Selection (3DHFC-TRS)," we assessed 231 alkaloid molecules from sunflower receptacles. Our clustering analysis pinpointed six alkaloids with significant gout-targeting potential, particularly emphasizing the fifth cluster's XO inhibition capabilities. Through molecular docking and the BatchDTA prediction model, we identified three top compounds—2-naphthylalanine, medroxalol, and fenspiride—with the highest XO affinity. Further molecular dynamics simulations assessed their enzyme active site interactions and binding free energies, employing MM-PBSA calculations. This investigation not only highlights the discovery of promising compounds within sunflower receptacle alkaloids via LC-MS but also introduces medroxalol as a novel gout treatment candidate, showcasing the synergy of computational techniques and LC-MS in drug discovery.

Assessment of Genetic Variability and Character Associations in Sunflower (Helianthus annuus L.) Yield Related Traits

Aims: To investigate yield and yield related characteristics for variability and association studies in fifty-two powdery mildew differentials of sunflower.
 Study Design: Augmented block design.
 Place and Duration of Study: Main agricultural Research station, University of Agricultural Science, Raichur, Karnataka between November 2022 and February 2023.
 Methodology: Study included 52 powdery mildew differentials of sunflower studied factors such as genetic variability, heritability, and genetic advance in characters such as head diameter, seed filling percent, test weight, number of seeds per head, volume weight, oil content and seed yield. Correlation and path analysis was also done.
 Results: Findings revealed significant differences among the traits, especially in seed yield per plant, head diameter, seed filling percent, test weight, and number of seeds per head which conclude that there is variability present in the studied character and there is scope for crop improvement. Correlation coefficients showed positive connections between seed yield per plant and traits like head diameter, test weight, seed filling percentage, and number of seeds per head. However, volume weight had a negative correlation. Path coefficient analysis helped us understand the direct and indirect impacts of these traits on seed yield per plant. Head diameter, seed filling percentage, test weight, and number of seeds per head had positive direct effects on seed yield per plant. In contrast, volume weight had a negative direct effect.
 Conclusion: The study contributes to the understanding of the genetic architecture of sunflower traits related to yield and provides a foundation for developing targeted breeding strategies. These insights can guide sunflower breeding programs in selecting traits for improved yield.

Genome-wide identification and expression analysis of the Dof gene family reveals their involvement in hormone response and abiotic stresses in sunflower (Helianthus annuus L.)

DNA binding with one finger (Dof), plant-specific zinc finger transcription factors, can participate in various physiological and biochemical processes during the life of plants. As one of the most important oil crops in the world, sunflower (Helianthus annuus L.) has significant economic and ornamental value. However, a systematic analysis of H. annuus Dof (HaDof) members and their functions has not been extensively conducted. In this study, we identified 50 HaDof genes that are unevenly distributed on 17 chromosomes of sunflower. We present a comprehensive overview of the HaDof genes, including their chromosome locations, phylogenetic analysis, and expression profile characterization. Phylogenetic analysis classified the 366 Dof members identified from 11 species into four groups (further subdivided into nine subfamilies). Segmental duplications are predominantly contributed to the expansion of sunflower Dof genes, and all segmental duplicate gene pairs are under purifying selection due to strong evolutionary constraints. Furthermore, we observed differential expression patterns for HaDof genes in normal tissues as well as under hormone treatment or abiotic stress conditions by analyzing RNA-seq data from previous studies and RT-qPCR data in our current study. The expression of HaDof04 and HaDof43 were not detected in any samples, which implied that they may be gradually undergoing pseudogenization process. Some HaDof genes, such as HaDof25 and HaDof30, showed responsiveness to exogenous plant hormones, such as kinetin, brassinosteroid, auxin or strigolactone, while others like HaDof15 and HaDof35 may participate in abiotic stress resistance of sunflower seedling. Our study represents the initial step towards understanding the phylogeny and expression characterization of sunflower Dof family genes, which may provide valuable reference information for functional studies on hormone response, abiotic stress resistance, and molecular breeding in sunflower and other species.

Effect of Foliar Application of Nano-Urea on Growth, Nutrient Uptake, Yield and Quality of Sunflower

The present field experiment was conducted during kharif season 2022-23 with a view to study the “Effect of foliar application of Nano-urea on growth,yield of sunflower. (Helianthus annuus L.)” The experiment was conducted in randomized block design and the treatment was ten with three replications. Results revealed that treatment T10- 100 % (RDN)+3 foliar sprays of Nano-urea 0.4 % at 30,45 and 60 DAS. recorded the highest seed and straw yield, growth parameters Which was significantly superior over all the treatments but was at par with treatmentT9-100% (RDN) + 2 foliar sprays of 0.4% Nano-urea at 45 and 60 DAS. Treatment T8- 100% RDN+1 foliar spray of 0.4 % Nano-urea at 30DAS and treatment T7-75 % RDN+ 3 foliar sprays of 0.4 % Nano-urea at 30, 45 and 60 DAS.

Influence of micronutrients on growth and productivity of kharif sunflower (Helianthus annuus L.)

Influence of micronutrients on growth and productivity of kharif sunflower (Helianthus annuus L.)

Optimizing the Performance of Sunflower (Helianthus annuus L.) Seed Shell-Derived Biochar for Lead Ion Adsorption

Optimizing the Performance of Sunflower (Helianthus annuus L.) Seed Shell-Derived Biochar for Lead Ion Adsorption

Alleviating Cd Stress in Sunflower (Helianthus annuus) through the Sodium Silicate Application

Sunflower has substantial potential for the remediation of heavy metals in soil, but its efficiency in Cd-contaminated soil is limited, with high concentrations of Cd causing stress in plants. Exogenous Si enhances plant tolerance to heavy metals, but the mechanism for enhancing the tolerance of oil sunflower under Cd stress is not known. In potting experiments, sunflowers were grown in soil with a Cd concentration of 11.8 mg/kg soil (the maximum value in the Zhundong coal mining area of Xinjiang) and five Si treatment levels (0, 50, 250, 500, and 1500 mg/kg soil). Exogenous Si improved sunflower development, gas exchange characteristics, and antioxidant enzyme activities in sunflower compared with the Cd-only control; exogenous Si application increased Cd concentrations in sunflower roots, stems, and leaves, and Cd was mainly concentrated in sunflower roots. Sunflower biomass increased by 13.83–114.18%, and gas exchange parameters increased by 16.95–36.03%, 30.06–66.82%, and 9.77–14.71%, respectively, as compared to the control. With the increase in sodium silicate concentrations, sunflower antioxidant enzyme activities increased by 8.81–150.28%, 91.35–351.55%, and 35.11–54.69%, respectively, and MDA content decreased by 3.34–25.14% as compared to Si0. Moreover, exogenous Si increased Cd uptake and minimized Cd stress in sunflowers at the seedling and blooming stages, and it potentially facilitated the phytoremediation of Cd-contaminated soils through enriched plants such as sunflower, as well as contributing to the achievement of sustainable development of the soil environment.

Effects of Pre-Emergence Herbicides on Weed Control and Yield of Safflower (Carthamus tinctorius L.) in Central Italy

Safflower is a multipurpose crop with several uses that can offer benefits to rainfed cereal-based cropping systems due to its tolerance to cold, drought, salinity, and its reduced need for agricultural inputs. Safflower requires good weed control for optimum yields because it is a very poor competitor with weeds, especially at the early growth stage, but registered pre-emergence herbicides are not available. This research investigated the effects of several pre-emergence herbicides on weed control and the yield of safflower in central Italy, through two field experiments in 2019 and 2020. Aclonifen, metazachlor, s-metolachlor, propyzamide, and metribuzin were applied as pre-emergence herbicides. The main weeds were the following: Papaver rhoeas L., Conyza canadensis (L.) Cronq., and Ammi majus L. in experiment 1, and wild sunflower (Helianthus annuus L.) in experiment 2. Metazachlor and metribuzin gave the highest phytotoxicity on safflower in both experiments, with values ranging from 48% to 75% and from 30% to 75% (in a scale of 0–100%), respectively, and seem to be not advisable as pre-emergence herbicides. Aclonifen, s-metolachlor, and propyzamide can be considered selective and safe to the safflower, showing the lowest values of phytotoxicity that ranged from 0 to 10%. Metazachlor and s-metolachlor gave the highest total weed control with values of 92% and 97%, respectively.

Comparative analysis of archival data on yields of main field crops from fertilizer experiments on different soil types in Bulgaria

The main aim of the study was to systematize and summarize archival data on yields from main field crops from multiple fertilizer experiments of Nikola Poushkarov ISSAPP on various soil types in Bulgaria. A large set of results from the field fertilizer experiments carried out on four different soil types: Calcareous Chernozem (Trastenik village), Haplic Chernozem (Gorni Dabnik village), Haplic Luvisol (Nikolaevo village) and Planosol (Sekirovo village) in the geographical network of Bulgaria of the Nikola Poushkarov ISSAPP has been accumulated. Eight fertilization variants were tested with annual application of potassium (0, 8, 16 and 32 kg/da K2 O) on two backgrounds of nitrogen (N) and phosphorus (P) fertilization. Crop rotation during the individual years was as follows: wheat (Triticum aestivum L.), maize (Zea mays L.), sunflower (Helianthus annuus L.) and sugar beet (Beta vulgaris L.), grown under non-irrigation conditions. Optimum rates of fertilization with the main nutrients, N, P and K have been established for the different soil types. There are complex interactions between the different rates of fertilization with the main macronutrients and this has a significant impact on the quantity and quality of agricultural crop yields. The difference in yields between the two investigated periods (1963-1970 and 1971-1975), at the same levels of fertilization, shows that the level of yields and accordingly, the use of nutrients are also determined to a significant extent by the climatic conditions. With an increase in the fertilizer rate, the yields also increase, and the rates of 16 kg and 32 kg K2 O remain the most effective, regardless of the occurrence of potassium accumulation in these variants. This was also confirmed by the results of the analysis of variance of the yields of cultivated crops. There was a pronounced increase of the effect of potassium fertilization in soils less supplied with this element, i.e. the Haplic Luvisol (Nikolaevo village) and Planosol (Sekirovo village). The effect of the potassium fertilization increases and expands in well supplied with potassium soils, but possessing unfavorable conditions for nutrition with this element, as in the case with the Calcareous Chernozem (Trastenik village). There was also an effect of potassium fertilization, although inconsistent, in soils well supplied with potassium, such as Haplic Chernozem (Gorni Dabnik village).

Evaluation of the tolerance and accumulation potential of selected sunflower hybrids grown in soil contaminated with cadmium

Common sunflower (Helianthus annuus L.) belongs to the group of crops with high biomass and high capacity for the accumulation of various metals. Previous studies have suggested that remedial potential is strongly determined by genotype. In our study, we evaluated the tolerance of six sunflower hybrids (P64HE118, P64LE136, P62LE122, P64HE133, P64HE144 and P63LP25) to cadmium ions (Cd 100 mg kg−1 soil), and we also evaluated their remediation potential. All tested hybrids showed high tolerance to Cd, no significant changes were noted with regard to growth, content of photosynthetic pigments, leaf area, water content, proline content, or accumulation of superoxide dismutase (SOD) isoforms. We noted an increased rate of membrane lipid peroxidation for P64HE118, P64LE136 and P64HE144 hybrids. The increased content of glutathione in the leaves of P64HE118 and P64LE136 hybrids indicates this molecule's involvement in the Cd detoxification process. All hybrids accumulated Cd preferentially in the roots. The most Cd was accumulated in the roots and shoots of hybrid P64HE118. Values of bioaccumulation factor and translocation factor were hybrid-dependent, being generally higher for standard/control soil (Cd 1.2 mg kg−1 soil). Better phytoremediation potential of these hybrids can hence be expected at lower Cd doses in the soil. The high tolerance of tested hybrids to a higher dose and the non-negligible accumulation of Cd in roots also supports using these hybrids in soil phytostabilisation.

Влияние на вегетационния хербицид Енвоке върху някои структурни елементи на продуктивността и добива от памук (Gossypium hirsutum L.)

Weeding during the growing season of cotton suppresses and slows down the growth and development of plants, and can lead to a significant reduction in yield and deterioration of fiber quality. The aim of this research was to study the effect of vegetation applied herbicide Envoke on the yield of cotton and some structural elements of productivity such as percent of boll opening and boll weight, under different agro-meteorological conditions. The research was conducted during the period 2020-2022 in the experimental field of the Field Crops Institute in Chirpan. In a three-factor field experiment, the effect of vegetation applied herbicide Envoke, containing 75% trifloxysulforon-sodium, was tested on two cotton varieties. Factor A included the three years of study. Factor B included the cultivars Chirpan-539 and Helius. Factor C included the herbicide Envoke applied in 3 doses - 10 g.ha-1, 15 g.ha-1 and 20 g.ha-1, once and twice during the 4-5 leaf and budding stages of cotton. It was established that when treated with the herbicide Envoke, the highest yield was obtained with the single treatment in the budding phase at a dose of 20 g.ha-1 for the cultivar Chirpan-539 and at a dose of 15 g.ha-1 for the cultivar Helius. Technologically valuable were found all variants with the herbicide Envoke in the cultivar Chirpan-539 and the variants in doses of 15 g.ha-1 and 20 g.ha-1 in the cultivar Helius. These options combined high yield values and high stability of this indicator in different years. The untreated controls in both cultivars were the only ones that received negative scores. This was due to the high number of weeds and self-sown sunflower (Helianthus annuus L.) plants. The vegetation herbicide Envoke, applied in three doses, once and twice during the 4-5 leaf and budding stages of cotton, had little influence on the percentage of boll opening and did not affect the boll weight at the treated variants of the two cotton cultivars - Chirpan-539 and Helius.

Synthesis of terpolymer from Helianthus annuus (natural oil) and evaluation as pour point depressant and viscosity reducer on Indian crude oil

Pour Point Depressant is introduced to crude oil at ppm level to overcome transportation problem of crude oil because of its complex chemical structure. Synthesized PPDs improve flow property, viscosity and also improve its numerous parameters to improve performance of crude oil. Low molecular weight and high molecular weight, copolymer having better PPD types. In present work, synthesized Terpolymer, from natural source, was formed from the reaction with Helianthus annuus oil and ester of Erucic Acid with various fatty alcohol. It was evaluated for its properties on Indian waxy crude oils, i.e., From Limbodra well. Structure and molecular weight of synthesized polymer was confirmed by Spectral data and Gel permeation chromatography (GPC). Also its effect on crude oil was evaluated by Rheological studies, SARA Analysis, Pour point depressant effect. Cross–polarizing microscopic studies were performed to study changes in morphology of wax crystals in crude oil with and without additive. A zero friction advanced Rheometer AR-500 was used to determine the viscosity by applying Bingham plastic-flow model.

Iron oxide nanoparticles improving multimetal phytoextraction in Helianthus annuus

This study assessed the phytotoxicity of a mixture of five different trace elements (TEs) frequently found as pollutants in soils: arsenic, cadmium, copper, lead and zinc. On the other hand, the plant response to a magnetite (Fe3O4) nanoparticle amendment on this mixture as well as nanomagnetite remediation potential has been tested. Sunflower (Helianthus annuus) plants were grown for 90 days in soil contaminated with the five mentioned TEs at the limit levels of TEs in soils likely to receive sludge established by French legislation. Depending on the conditions, experimental set-ups were amended or not with 1% dry weight nanomagnetite (NPsMagn), citric acid-coated nanomagnetite (NPsMagn@CA) or micro-sized magnetite (μPs) in order to assess the behavior of nanomagnetites in a TEs-contaminated water-soil-plant system under repeated water-deficiency stress. The mixture of TEs did not induce phytotoxicity as estimated by plant growth, pigment content, maximum quantum yield of photosynthesis, oxidative impact and antioxidant response. Furthermore, both nanomagnetites treatments in a TEs-contaminated soil significantly increased biomass production by 64 % compared to control and antioxidant enzyme activities compared to control and TEs-treated plants. NPsMagn and NPsMagn@CA particularly enhance phytoextraction of Cd and Cu, increasing the amounts of TEs in aerial parts from 1.5 to 4.5 times compared to set-ups without nanomagnetites. Based on Cd, Cu, Pb and Zn contents in soil solutions, both nanomagnetites treatments improved TEs phytoextraction without increasing groundwater contamination. On the contrary, nanomagnetites significantly reduce arsenic uptake by plants and solubilization in dissolved phase. Our results show that modifying surface physicochemical properties of NPsMagn with citric acid coating does not improve their effects compared to bare NPsMagn. NPsMagn and NPsMagn@CA also appear to mitigate the effects of drought stress. This work highlights several positive environmental aspects related to the use of nanomagnetites in phytoremediation.

Assessment of the Potential of Sunflower Grown in Metal-Contaminated Soils for Production of Biofuels

Environmental biotechnology needs solutions that are associated with a low budget and cleaner remediation, and which are connected to resources and energetic valorization, to be able to encourage a circular bioeconomy. A prospective resolution for heavy-metal-contaminated soils is the application of phytoremediation approaches merged with bioenergy generation using the resulting biomass. Sunflower (Helianthus annuus) has been studied as a feedstock for biodiesel generation, and appears to be very attractive for biogas and bioethanol production. The current study reports an innovative energetic valorization approach of H. annuus biomass derived from the application of a phytoremediation strategy devised to remove Zn and Cd from an industrially contaminated soil (599 mg Zn kg−1 and 1.2 mg Cd kg−1)—and its comparison to the analysis of the same energetic valorization pathway for sunflower plants growing in an agricultural non-contaminated soil. After plant harvesting, bioethanol was produced from the aboveground tissues, and applied in the transesterification of the oil obtained through seed extraction for the generation of biodiesel. Also, biogas production was assessed through the root’s biomass anaerobic digestion. Similar yields of oil extraction—0.32 and 0.28 mL g−1 DW—were obtained when using seeds from H. annuus cultured in contaminated and non-contaminated soils, respectively. The production yield of bioethanol was superior using biomass from the agricultural non-contaminated soil (0.29 mL g−1 DW) when compared to the industrial metal-contaminated soil (0.20 mL g−1 DW). Zinc was measured in minor levels in bioethanol and oil (ca. 1.1 and 1.8 mg mL−1, correspondingly) resulting from the biomass cultivated in the industrialized soil, whereas Cd was not detected. The production yield of biogas was superior when using root biomass from H. annuus cultivated in agricultural non-contaminated soil (VS max. ca. 104 mL g−1) when compared to the one deriving from the industrial contaminated soil (VS max ca. 85 mL g−1). Generally, results demonstrate that substantial production yields of the tested biofuels were attained from biomass resulting from phytoremediation, corroborating this integrated original approach as a valuable alternative for the phytoremediation of HM-polluted soils and as an important strategy for plant biomass valorization.