Search

The response of mesophyll conductance (gm) to CO2 plays a key role in photosynthesis and ecosystem carbon cycles under climate change. Despite numerous studies, there is still debate about how gm responds to short‐term CO2 variations. Here we used multiple methods and looked at the relationship between stomatal conductance to CO2 (gsc) and gm to address this aspect. We measured chlorophyll fluorescence parameters and online carbon isotope discrimination (Δ) at different CO2 mole fractions in sunflower (Helianthus annuus L.), cowpea (Vigna unguiculata L.), and wheat (Triticum aestivum L.) leaves. The variable J and Δ based methods showed that gm decreased with an increase in CO2 mole fraction, and so did stomatal conductance. There were linear relationships between gm and gsc across CO2 mole fractions. gm obtained from A‐Ci curve fitting method was higher than that from the variable J method and was not representative of gm under the growth CO2 concentration. gm could be estimated by empirical models analogous to the Ball‐Berry model and the USO model for stomatal conductance. Our results suggest that gm and gsc respond in a coordinated manner to short‐term variations in CO2, providing new insight into the role of gm in photosynthesis modelling. Summary statement: For photosynthesis modelling, the response of gm to short‐term CO2 changes is essential. Using variable J and carbon isotope discrimination methods, we showed that gm decreased with an increase in CO2 mole fraction, which contradicts the assumption of a constant gm in photosynthesis models. [ABSTRACT FROM AUTHOR]

The state of Rio Grande do Sul (RS) is the third largest sunflower producer in Brazil. This study verified the existence of linear relationships between grain yield, oil content, and oil yield in sunflower (Helianthus annuus L.) genotypes evaluated in RS. The data on grain yield (GY), oil content (OC), and oil yield (OY) were obtained from 73 sunflower cultivar trials in 21 municipalities in RS from 1999 to 2018. Scatter diagrams were createdto investigate the relationships between the variables GY, OC, and OY. Then, Pearson's linear correlation coefficient (r) was calculated between the variables, and the Student's t-test was performed at a 5% significance level. There is a positive and significant linear relationship between PG and OY. However, no linear relationship was found between grain yield and oil content in sunflower genotypes. Additionally, a positive linear association of high magnitude (r = 0.9672) was observed between grain yield and oil yield, while a low magnitude (r = 0.2245) was found between oil content and oil yield. [ABSTRACT FROM AUTHOR]

Virus-Induced Gene Silencing (VIGS) is a versatile tool in plant science, yet its application to non-model species like sunflower demands extensive optimization due to transformation challenges. In this study, we aimed to elucidate the factors that significantly affect the efficiency of Agrobacterium-VIGS in sunflowers. After testing a number of approaches, we concluded that the seed vacuum technique followed by 6 h of co-cultivation produced the most efficient VIGS results. Genotype-dependency analysis revealed varying infection percentages (62–91%) and silencing symptom spreading in different sunflower genotypes. Additionally, we explored the mobility of tobacco rattle virus (TRV) and phenotypic silencing manifestation (photo-bleaching) across different tissues and regions of VIGS-infected sunflower plants. We showed the presence of TRV is not necessarily limited to tissues with observable silencing events. Finally, time-lapse observation demonstrated a more active spreading of the photo-bleached spots in young tissues compared to mature ones. This study not only offers a robust VIGS protocol for sunflowers but also provides valuable insights into genotype-dependent responses and the dynamic nature of silencing events, shedding light on TRV mobility across different plant tissues. [ABSTRACT FROM AUTHOR]

One of the most important oil crops in the world, sunflower (Helianthus annuus L.), is recognized to help in soil phytoremediation. Heavy metal (HM) contamination is one of the most abiotic challenges that may affect the growth and productivity of such an important crop plant. We studied the influence of HM-contaminated soils on metal homeostasis and the potential hypertolerance mechanisms in two sunflower Egyptian cultivars (V120 and S53). Both cultivars accumulated significantly higher cadmium concentrations in their roots compared to their shoots during Cd and Zn/Cd treatments. Higher root concentrations of 121 mg g−1 dry weight (DW) and 125 mg g−1 DW were measured in V120 plants compared to relatively lower values of 111 mg g−1 DW and 105 mg g−1 DW in the roots of S53 plants, respectively. Cadmium contamination significantly upregulated the expression of heavy metal ATPases (HaHMA4) in the shoots of V120 plants. On the other hand, their roots displayed a notable expression of HaHMA3. This study indicates that V120 plants accumulated and sequestered Cd in their roots. Therefore, it is advised to cultivate the V120 cultivar in areas contaminated with heavy metals as it is a promising Cd phytoremediator. The current study confirms and provides new insights into the low Cd and Zn concentration responses of two cultivars of Helianthus annuus as potential HM phytoremediators. HMA3 and HMA4 mediated both root sequestration and reduced root-to-shoot translocation rates. Moreover, high CAT and POX activities may reduce oxidative damage and enhance plant tolerance. The V120 showed higher levels of Cd accumulation in its roots and could be a promising cultivar for the phytoremediation of this heavy metal. This work recalls that Cd tolerance is a trait that may vary among cultivars of the same species and should be taken into consideration in the phytomanagement of heavy metals in contaminated soils. [ABSTRACT FROM AUTHOR]

We present a reference genome for the federally endangered Gaviota tarplant, Deinandra increscens subsp. villosa (Madiinae, Asteraceae), an annual herb endemic to the Central California coast. Generating PacBio HiFi, Oxford Nanopore Technologies, and Dovetail Omni-C data, we assembled a haploid consensus genome of 1.67 Gb as 28.7 K scaffolds with a scaffold N50 of 74.9 Mb. We annotated repeat content in 74.8% of the genome. Long terminal repeats (LTRs) covered 44.0% of the genome with Copia families predominant at 22.9% followed by Gypsy at 14.2%. Both Gypsy and Copia elements were common in ancestral peaks of LTRs, and the most abundant element was a Gypsy element containing nested Copia/Angela sequence similarity, reflecting a complex evolutionary history of repeat activity. Gene annotation produced 33,257 genes and 68,942 transcripts, of which 99% were functionally annotated. BUSCO scores for the annotated proteins were 96.0% complete of which 77.6% was single copy and 18.4% duplicates. Whole genome duplication synonymous mutation rates of Gaviota tarplant and sunflower (Helianthus annuus) shared peaks that correspond to the last Asteraceae polyploidization event and subsequent divergence from a common ancestor at ∼27 MYA. Regions of high-density tandem genes were identified, pointing to potentially important loci of environmental adaptation in this species. [ABSTRACT FROM AUTHOR]

To maximize their fitness, plants have to adjust their allocation strategy according to their abiotic and biotic environments. Plants can use the ratio of red to far‐red light (R:FR) to sense neighbours, allowing them to modify their growth in response to aboveground competition.In this study, we used supplemental FR light to artificially lower the R:FR of the lower leaves of common sunflowers (Helianthus annuus) to examine how plants change their growth in response to the threat of neighbours. We combined this treatment with a nitrogen fertilization treatment to investigate how responses to neighbour‐detection interact with nitrogen limitation.Plants grown in low R:FR increased in height at the expense of root growth, resulting in nitrogen limitation that restricted leaf growth. However, we found that plants reduced their nitrogen investment into leaves in low R:FR. By weakening the nitrogen sink strength of these lower leaves before they experienced low photosynthetically active radiation, plants were able to preemptively allocate nitrogen to leaves higher in the canopy.Plants responded to the perception of neighbours by simultaneously diverting resources from root growth to stem elongation and from leaves threatened by neighbours to leaves that would pose a threat to neighbours. This whole‐plant response to neighbour‐detection enables plants to change their allocation in a way that simultaneously manages their limited nitrogen and prepares them for future light competition. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Drought stress poses a significant obstacle to agricultural productivity, particularly in the case of oilseed crops such as sunflower (Helianthus annuus L.). Selenium (Se) is a fundamental micronutrient that has been recognized for its ability to enhance plant resilience in the face of various environmental stresses. The FH-770 sunflower variety was cultivated in pots subjected to three stress levels (100% FC, 75% FC, and 50% FC) and four Se application rates (0 ppm, 30 ppm, 60 ppm, and 90 ppm). This research aimed to investigate the effect of exogenously applied Se on morpho-physiological and biochemical attributes of sunflower to improve the drought tolerance. Foliar Se application significantly lowered H2O2 (hydrogen peroxide; ROS) (20.89%) accumulation that markedly improved glycine betaine (GB) (74.46%) and total soluble protein (Pro) (68.63%), improved the accumulation of ascorbic acid (AA) (25.51%), total phenolics (TP) (39.34%), flavonoids (Flv) (73.16%), and anthocyanin (Ant) (83.73%), and improved the activity of antioxidant system superoxide dismutase (SOD) (157.63%), peroxidase (POD) (100.20%), and catalase (CAT) (49.87%), which ultimately improved sunflower growth by 36.65% during drought stress. Supplemental Se significantly increased shoot Se content (93.86%) and improved calcium (Ca2+), potassium (K+), and sodium (Na+) ions in roots by 36.16%, 42.68%, and 63.40%, respectively. Seleniumsupplements at lower concentrations (60 and 90 ppm) promoted the growth, development, and biochemical attributes of sunflowers in controlled and water-deficient circumstances. However, selenium treatment improved photosynthetic efficiency, plant growth, enzymatic activities, osmoregulation, biochemical characteristics, and nutrient balance. The mechanisms and molecular processes through which Se induces these modifications need further investigation to be properly identified. [ABSTRACT FROM AUTHOR]

The quality of river and borehole water fluctuates because of both agricultural and industrial pollutants. Surface runoff during the rainy seasons is high which promote increased turbidity levels in water sources, and this exerts pressure on the quality and usability of the water for domestic use. Unfortunately, most municipalities in developing countries are poor to afford conventional water treatment methods. This study assessed the use of natural coagulants extracted from sunflower seeds for turbidity treatment. Water samples were collected during summer, winter, and autumn from 10 randomly selected groundwater sources and three segments of the Mwerahari River in Buhera District, Zimbabwe. Results captured seasonal turbidity variations across the river segments and the boreholes. Summer season recorded the maximum average levels of turbidity (76 NTU) while autumn and winter recorded 38.7 NTU 36.7 NTU, respectively. Water turbidity levels were above the acceptable 5 NTU Standard Association of Zimbabwe and WHO. The maximum removal efficiency of turbidity was achieved at 80 min at the dose of 4 g/l. These results revealed that the removal efficiency of 95% with 4.6 NTU turbidity is a function of dose; removal efficiency increases as dose of coagulant increases. These results demonstrated that sunflower seed is an effective low-cost natural coagulant for turbidity water treatment. [ABSTRACT FROM AUTHOR]

Sunflower (Helianthus annuus L.), a vital crop for global vegetable oil production, encounters sustainability challenges in its cultivation. This study assesses the effects of incorporating a winter cover crop (CC), Avena sativa (L.), on the subsequent growth of sunflower crops and the vitality of their rhizosphere microbial communities over a two-year period. It examines the impact of two methods for suppressing winter CC--chemical suppression using glyphosate and mechanical suppression via rolling--both with and without the addition of phosphorus (P) starter fertilizer. These approaches are evaluated in comparison to the regional best management practices for sunflower cultivation, which involve a preparatory chemical fallow period and the subsequent application of starter P fertilizer. The methodology utilized Illumina sequencing for the analysis of rhizosphere bacterial 16S rRNA genes and fungal internal transcribed spacer (ITS) amplicons. Findings indicate a significant improvement (9-37%) in sunflower growth parameters (plant height, stem diameter, head diameter, and head dry weight) when cultivated after glyphosate-suppressed winter CC compared to the chemical fallows. Conversely, rolling of winter CC generally negatively affected sunflower growth. Rhizosphere bacterial communities following chemical suppression of winter CC showed greater Pielou's evenness, indicating a uniform distribution of species. In general, this treatment had more detrimental effects on beneficial sunflower rhizosphere bacteria such as Hymenobacter and Pseudarthrobacter than rolling of the winter CC, suggesting that the overall effect on sunflower growth may be mitigated by the redundancy within the bacterial community. As for fungal diversity, measured by the Chao-1 index, it increased in sunflowers planted after winter CC and receiving P fertilization, underscoring nutrient management's role in microbial community structure. Significant positive correlations between fungal diversity and sunflower growth parameters at the reproductive stage were observed (r = 0.41-0.72; p < 0.05), highlighting the role of fungal communities in plant fitness. The study underscores the positive effects of winter CC inclusion and management for enhancing sunflower cultivation while promoting beneficial microbes in the crop's rhizosphere. We advocate for strategic winter CC species selection, optimization of mechanical suppression techniques, and tailored phosphorus fertilization of sunflower to foster sustainable agriculture. [ABSTRACT FROM AUTHOR]

Summary: Vascular systems are intimately related to the shape and spatial arrangement of the plant organs they support. We investigate the largely unexplored association between spiral phyllotaxis and the vascular system in Asteraceae flower heads.We imaged heads of eight species using synchrotron‐based X‐ray micro‐computed tomography and applied original virtual reality and haptic software to explore head vasculature in three dimensions. We then constructed a computational model to infer a plausible patterning mechanism.The vascular system in the head of the model plant Gerbera hybrida is qualitatively different from those of Bellis perennis and Helianthus annuus, characterized previously. Cirsium vulgare, Craspedia globosa, Echinacea purpurea, Echinops bannaticus, and Tanacetum vulgare represent variants of the Bellis and Helianthus systems. In each species, the layout of the main strands is stereotypical, but details vary. The observed vascular patterns can be generated by a common computational model with different parameter values.In spite of the observed differences of vascular systems in heads, they may be produced by a conserved mechanism. The diversity and irregularities of vasculature stand in contrast with the relative uniformity and regularity of phyllotactic patterns, confirming that phyllotaxis in heads is not driven by the vasculature. See also the Commentary on this article by Burian & Kierzkowski, 243: 10–13. [ABSTRACT FROM AUTHOR]

Sunflower (Helianthus annuus) is an important oil crop, ranking behind soybean, peanut, and rapeseed in terms of planting area in China. Throughout its cultivation, sunflower is susceptible to various diseases that can significantly reduce its seed yield. Among them, Fusarium species pose a major threat to numerous crops. The accurate identification of Fusarium species responsible for specific diseases is crucial for developing effective control measures. In Inner Mongolia, sunflower disk rot (SDR) has been observed in various sunflower fields, with an average infection rate of approximately 8.50%. The infection rate can reach up to 11.67% in certain highly susceptible cultivars. Samples of diseased sunflower receptacles were collected from different locations, and Koch's postulates were employed to identify the causal agent. The results confirmed Fusarium verticillioides as the pathogen responsible for SDR. Fungicide toxicity tests were conducted, screening six fungicides for efficacy against F. verticillioides. Fludioxonil and Flutolanil were identified as the most effective, with EC50 values of 0.05 µg/mL (R = 0.9825) and 0.96 µg/mL (R = 0.9964), respectively. This is the first report of SDR caused by F. verticillioides, and it will alert sunflower researchers to include SDR in the disease list, so as to control sunflower diseases with integrated management strategies successfully. [ABSTRACT FROM AUTHOR]

The sunflower (Helianthus annuus L.) is one of the most essential oil crops in the world. Several component traits, including flowering time, plant height, stem diameter, seed weight, and kernel weight, determine sunflower seed and oil yield. Although the genetic mechanisms governing the variation of these yield-related traits have been studied using various approaches, genome-wide association studies (GWAS) have not been widely applied to sunflowers. In this study, a set of 342 sunflower accessions was evaluated in 2019 and 2020 using an incomplete randomized block design, and GWAS was conducted utilizing two complementary approaches: the mixed linear model (MLM) and the fixed and random model circulating probability unification (farmCPU) model by fitting 226,779 high-quality SNPs. As a result, GWAS identified a number of trait-associated SNPs. Those SNPs were located close to several genes that may serve as a basis for further molecular characterization and provide promising targets for sunflower yield improvement. [ABSTRACT FROM AUTHOR]

Stress-associated proteins (SAPs) are known to play an important role in plant responses to abiotic stresses. This study systematically identified members of the sunflower SAP gene family using sunflower genome data. The genes of the sunflower SAP gene family were analyzed using bioinformatic methods, and gene expression was assessed through fluorescence quantification (qRT-PCR) under salt and drought stress. A comprehensive analysis was also performed on the number, structure, collinearity, and phylogeny of seven Compositae species and eight other plant SAP gene families. The sunflower genome was found to have 27 SAP genes, distributed across 14 chromosomes. The evolutionary analysis revealed that the SAP family genes could be divided into three subgroups. Notably, the annuus variety exhibited amplification of the SAP gene for Group 3. Among the Compositae species, C. morifolium demonstrated the highest number of collinearity gene pairs and the closest distance on the phylogenetic tree, suggesting relative conservation in the evolutionary process. An analysis of gene structure revealed that Group 1 exhibited the most complex gene structure, while the majority of HaSAP genes in Group 2 and Group 3 lacked introns. The promoter analysis revealed the presence of cis-acting elements related to ABA, indicating their involvement in stress responses. The expression analysis indicated the potential involvement of 10 genes (HaSAP1, HaSAP3, HaSAP8, HaSAP10, HaSAP15, HaSAP16, HaSAP21, HaSAP22, HaSAP23, and HaSAP26) in sunflower salt tolerance. The expression of these 10 genes were then examined under salt and drought stress using qRT-PCR, and the tissue-specific expression patterns of these 10 genes were also analyzed. HaSAP1, HaSAP21, and HaSAP23 exhibited consistent expression patterns under both salt and drought stress, indicating these genes play a role in both salt tolerance and drought resistance in sunflower. The findings of this study highlight the significant contribution of the SAP gene family to salt tolerance and drought resistance in sunflower. [ABSTRACT FROM AUTHOR]

The development of floral organs, crucial for the establishment of floral symmetry and morphology in higher plants, is regulated by MADS-box genes. In sunflower, the capitulum is comprised of ray and disc florets with various floral organs. In the sunflower long petal mutant (lpm), the abnormal disc (ray-like) floret possesses prolongated petals and degenerated stamens, resulting in a transformation from zygomorphic to actinomorphic symmetry. In this study, we investigated the effect of MADS-box genes on floral organs, particularly on petals, using WT and lpm plants as materials. Based on our RNA-seq data, 29 MADS-box candidate genes were identified, and their roles on floral organ development, especially in petals, were explored, by analyzing the expression levels in various tissues in WT and lpm plants through RNA-sequencing and qPCR. The results suggested that HaMADS3, HaMADS7, and HaMADS8 could regulate petal development in sunflower. High levels of HaMADS3 that relieved the inhibition of cell proliferation, together with low levels of HaMADS7 and HaMADS8, promoted petal prolongation and maintained the morphology of ray florets. In contrast, low levels of HaMADS3 and high levels of HaMADS7 and HaMADS8 repressed petal extension and maintained the morphology of disc florets. Their coordination may contribute to the differentiation of disc and ray florets in sunflower and maintain the balance between attracting pollinators and producing offspring. Meanwhile, Pearson correlation analysis between petal length and expression levels of MADS-box genes further indicated their involvement in petal prolongation. Additionally, the analysis of cis-acting elements indicated that these three MADS-box genes may regulate petal development and floral symmetry establishment by regulating the expression activity of HaCYC2c. Our findings can provide some new understanding of the molecular regulatory network of petal development and floral morphology formation, as well as the differentiation of disc and ray florets in sunflower. [ABSTRACT FROM AUTHOR]

Introduction: Arsenate, a metalloid, acting as an analog to phosphate, has a tendency to accumulate more readily in plant species, leading to adverse effects. Methods: In the current study, sunflower seedlings were exposed to 25, 50 and 100 ppm of the arsenic. Results: Likewise, a notable reduction (p<0.05) was observed in the relative growth rate (RGR) by 4-folds and net assimilation rate (NAR) by 75% of Helianthus annuus when subjected to arsenic (As) stress. Nevertheless, the presence of Staphylococcus arlettae, a plant growth-promoting rhizobacterium with As tolerance, yielded an escalation in the growth of H. annuus within Ascontaminated media. S. arlettae facilitated the conversion of As into a form accessible to plants, thereby, increasing its uptake and subsequent accumulation in plant tissues. S. arlettae encouraged the enzymatic antioxidant systems (Superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX) and catalase (CAT)) and non-enzymatic antioxidants (flavonoids, phenolics, and glutathione) in H. annuus seedlings following substantial As accumulation. The strain also induced the host plant to produce osmolytes like proline and sugars, mitigating water loss and maintaining cellular osmotic balance under As-induced stress. S. arlettae rectified imbalances in lignin content, reduced high malonaldehyde (MDA) levels, and minimized electrolyte leakage, thus counteracting the toxic impacts of the metal. Conclusion: The strain exhibited the capability to concurrently encourage plant growth and remediate Ascontaminated growth media through 2-folds rate of biotransformation and bio-mobilization. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sunflower line HA 488 (where HA is Helianthus annuus) is resistant to the red sunflower seed weevil, Smicronyx fulvus LeConte, with ≈80% less seed damage compared to susceptible lines. To determine the value of resistance in single‐cross hybrids, six hybrids were created by pollinating weevil‐resistant (cms HA 488, where cms cytoplasmic male sterile) or susceptible (cms HA 412HO) inbred lines with three putatively susceptible restorer lines (RHA 274, RHA 464, or RHA 468) and artificially infesting each with 30 weevils head−1. In 2021–2022, resistant hybrids from cms HA 488 reduced seed damage by ≈40%–50% for hybrids with RHA 274 or RHA 464. However, cms HA 488 did not reduce damage when crossed with RHA 468. Infestation of male‐fertile isogenic lines HA 488 and HA 412HO with 60 weevils head−1 showed resistance remained effective at 12–20 times economic thresholds. Results confirm the value of resistance to S. fulvus for sunflower hybrids but also suggest a need to further examine the role of the male heterotic group in resistance to the red sunflower seed weevil. Core Ideas: Inbred cms HA 488 reduced seed weevil damage ≈40%–50% in single‐cross hybrids.Some male (RHA) parents may provide non‐complementary resistance.Field trials showed resistance in HA 488 per se was effective at 12–20 times economic thresholds. [ABSTRACT FROM AUTHOR]

Drought stress poses a significant threat to agricultural productivity, especially in areas susceptible to water scarcity. Sunflower (Helianthus annuus L.) is a widely cultivated oilseed crop with considerable potential globally. Jasmonic acid, a plant growth regulator, plays a crucial role in alleviating the adverse impacts of drought stress on the morphological, biochemical, and physiological characteristics of crops. Experimental detail includes sunflower varieties (Armani Gold, KQS-HSF-1, Parsun, and ESFH-3391), four drought stress levels (0, 25%, 50%, and 75% drought stress), and three levels (0, 40ppm, 80ppm) of jasmonic acid. The 0% drought stress and 0ppm jasmonic acid were considered as control treatments. The experimental design was a completely randomized design with three replicates. Drought stress significantly reduced the growth in all varieties. However, the exogenous application of jasmonic acid at concentrations of 40ppm and 80ppm enhanced growth parameters, shoot and root length (1.93%, 19%), shoot and root fresh weight (18.5%, 25%), chlorophyll content (36%), photosynthetic rate (22%), transpiration rate (40%), WUE (20%), MDA (6.5%), Phenolics (19%), hydrogen peroxide (7%) proline (28%) and glycine betaine (15–30%) under water-stressed conditions, which was closely linked to the increase in stomatal activity stimulated by jasmonic acid. Furthermore, JA 80 ppm was found to be the most appropriate dose to reduce the effect of water stress in all sunflower varieties. It was concluded that the foliar application of JA has the potential to enhance drought tolerance by improving the morphological, biochemical, and physiological of sunflower. [ABSTRACT FROM AUTHOR]

Sclerotinia head rot, caused by Sclerotinia sclerotiorum, is a major disease limiting sunflower production in tropical and subtropical agroecological zones. Sporadic outbreaks across South Africa have resulted in major losses, yet little is known about the in‐field climatic factors driving this infection. Short‐interval, staggered plantings have been proposed as a control method for Sclerotinia head rot, which help to limit the number of plants in a susceptible developmental stage during conducive environmental conditions. However, this complicates field management practices, especially if working at the fringes of a planting window due to delayed rains. This study aimed to investigate the effect of planting date on Sclerotinia head rot progression in monthly plantings across the summer period. Artificial mycelial plug inoculations were performed at the R5.9 flowering stage in an open field. Disease establishment, progression and severity were monitored at 3‐day intervals for 30 days. We show that disease establishment was delayed by low relative humidity or extreme low temperatures in the January and March planting dates where the first lesions were only observed 6 days post‐inoculation. Consistently high temperatures above 27°C also suppressed disease progression and produced low area under the disease progress curve (AUDPC) scores of 75.15 and 29.4 for the October and November planting dates, respectively. These findings suggest that regardless of season or location, selecting a planting date that ensures the sunflower bloom period aligns with the hottest, driest part of the season will probably suppress Sclerotinia head rot in regions with average summer highs above 27°C. [ABSTRACT FROM AUTHOR]

The present investigation was performed to evaluate the effects of various synthetic antioxidants (vitamin A, vitamin E, β-carotene, and BHT) on the oxidation of sunflower oil subjected to accelerated thermal storage at 60 °C for three months (12 weeks). The performance of the antioxidants studied was evaluated using several quality parameters: the free fatty acid value (FFA), primary oxidation (via the peroxide value (PV) and K232 value), secondary oxidation products (via the anisidine value (p-AV) and K270 value), and the total oxidation value (TOTOX). The fatty acid composition (FAC), oxidizability value (COX), iodine value (IV), and pigment content (chlorophyll and carotenoid) were also evaluated. The results revealed that the control sample of sunflower oil exhibited higher susceptibility to oxidative deterioration. Antioxidants at 200 ppm were more effective in preserving the oxidative stability of sunflower oil subjected to accelerated storage compared to the control oil. The smallest increases in all stability parameter indexes were recorded for antioxidant-supplemented sunflower oil. However, the IV and chlorophyll and carotenoid contents were reduced. At 200 ppm, vitamin E and β-carotene showed the greatest stability in sunflower oil, while their combination with vitamin A at 100 ppm of each showed the lowest stability. In addition, synthetic antioxidants provided greater protection against the degradation of polyunsaturated fatty acids (PUFAs). The highest level of PUFA degradation was recorded in the control oil, followed by the oil containing vitamin A. In conclusion, adding synthetic antioxidants to sunflower oil improves its stability during storage. However, some authors associated these molecules with a health risk due to carcinogenic effects as these molecules have been listed as "Generally Recognized As Safe" (GRAS). [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the potential of using the germination test as a model for screening imazamox resistance in sunflower plants . A standard germination test was performed by applying different doses of imazamox (control, 0.1, 0.2, 0.4, 0.8, and 1.6 mM) to imidazoline-resistant (IMI-R) and susceptible (IMI-S) sunflower hybrids. Germination percentage, mean germination time, germination index, shoot length, root length, seedling fresh and dry weight, and phytotoxicity percentage for seedling growth parameters were investigated. The results showed that imazamox concentrations slightly affected the germination percentage of two sunflower hybrids at only 1.6 mM. Increasing doses of imazamox led to an increase in the mean germination time and a decrease in the germination index for both sunflower hybrids, following a similar trend. Seedling growth parameters such as shoot length, root length, and seedling fresh weight were significantly decreased by increasing imazamox doses. In addition, the differences between IMI-R and IMI-S sunflower hybrids were very evident for these parameters. The IMI-S sunflower hybrid showed sensitivity in the presence of imazamox, while no changes in the IMI-R hybrid were determined up to 0.4 mM. The inhibition percentage was higher in the IMI-S hybrid than in the IMI-R. It was concluded that the optimal dose of imazamox for the selection of resistant plants during the early growth stage was found to be 0.2 mM. The germination parameters were not good criteria for imazamox resistance, while root length, shoot length, and seedling fresh weight should be considered as selection criteria for resistance to imazamox in sunflower. [ABSTRACT FROM AUTHOR]

Plant growth-promoting rhizobacteria (PGPR) support plant growth through direct and indirect mechanisms. To investigate PGPR strains that support plant growth, 21 bacterial isolates, mostly Bacillus ssp. and Pseudomonas ssp., were isolated from different rhizospheric soils of sunflowers in Kırşehir districts in 2020. All isolates were characterized morphologically, biochemically by screening under in vitro conditions for plant growth-promoting properties such as nitrogen fixation, IAA (indoleacetic acid) production, siderophore production, HCN (hydrogen cyanide) production, inorganic phosphate solubility. It was also screened for extracellular enzyme production and antifungal activity against Fusarium oxysporum. Among the 21 isolates, 3 isolates (MH-35-4, MH-49-4, MH-64-3) fixed nitrogen, 2 isolates (MH-59-6, MH-64-3), produced siderophores, 8 isolates (MH-35-4, MH-35-6, MH-54-3, MH-54-4, MH-59-1, MH-59-2, MH-59-4, MH-59-8) produced HCN, 6 isolates (MH-35-6, MH-54-4, MH-59-1, MH- 59-2, MH-59-4, MH-59-8) produced IAA, and 7 isolates (MH-35-4, MH-35-6, MH-59-1, MH-59-2, MH-59-4, MH-59-8, MH-64-3) solubilized inorganic phosphate. Additionally, only 2 isolates (MH-54-3, MH-54-4) were positive amylase tests, 8 isolates (MH-35-6, MH-54-4, MH-59-1, MH-59-2, MH-59-4, MH-59-6, MH-59-7, MH-59-8) were positive citrate tests, 8 isolates (MH-35-1, MH-35-4, MH-35-7, MH-49-4, MH-54-4, MH-59-6, MH-59-7, MH-64-3) were positive protease tests, and 6 isolates (MH-35-1, MH-35-3, MH-35-7, MH-54-3, MH-54-4, MH-59-7) were positive gelatin hydrolysis tests. Among 21 isolates, 38% were determined as hydrogen cyanide producers, 10% as siderophore producers, 29% IAA producers, 33% as phosphate solubilizers and 14% as nitrogen fixers. Isolate MH-35-6 showed the highest antifungal activity against Fusarium oxysporum with an inhibition rate of 53.57%. This was followed by isolates MH-54-1 (51.19%), MH-54-3 (47.61%) and MH-59-2 (38.09%), respectively. Therefore, our study reveals that bacteria that promote plant growth in sunflowers can be used to increase crop yield and as a biocontrol agent. [ABSTRACT FROM AUTHOR]

Resistance of agricultural crops to herbicides is an important topic that concerns many researchers. One of the most popular groups of herbicides is the imidazolinone group. Resistant forms of crops such as wheat (Triticum aestivum L.), sunflower (Helianthus annuus L.), corn (Zea mays L.), rice (Oryza sativa L.) and oilseed rape (Brassica napus L.) have been developed to this group of herbicides. All crops resistant to this group of herbicides have the commercial name Clearfield®. In this review, the information concerning oilseed rape resistance to the imidazolinone group of herbicides is collected and summarized; it will be useful for breeders and researchers engaged in this direction. This review touches upon the topic of mechanisms of oilseed rape resistance to imidazolinones. Mutation variants known to date, which provide resistance to this group of herbicides, are described, and known molecular markers of them are presented. Approaches to the selection of oilseed rape for resistance to the imidazolinone group of herbicides are mentioned. Various methods of utilizing imidazolinone resistance to improve the purity of hybrid seeds are also considered. [ABSTRACT FROM AUTHOR]

Microorganisms with multiple ecological functions can be a useful biotechnological resource in integrated pest- and disease-management programs. This work aimed to investigate the potential endophytic and virulent effects of a strain of Purpureocillium lilacinum on organic cultivation in Brazil. Specifically, the strain's ability to establish itself as an endophyte in common bean, soybean, and sunflower plants when inoculated via seed was evaluated. Furthermore, its antifungal activity against phytopathogens and its pathogenicity and virulence against insects of the order Lepidoptera, Coleoptera, and Hemiptera were evaluated. Furthermore, the strain was evaluated for its biochemical and physiological characteristics. For virulence bioassays, the experiments were conducted under a factorial scheme (2 × 3), with the following factors: (a) fungal inoculation and control without inoculum and (b) types of inocula (blastospores, aerial conidia, and metabolites). The treatments were sprayed on insect species at different stages of development. In summary, it was found that the SBF054 strain endophytically colonized the common bean, with partial recovery from the root tissues of soybean and sunflower plants, 30 days after inoculation; suppressed 86% of Rhizoctonia solani mycelial growth in an in vitro assay; and controlled eggs, nymphs, and Euschistus heros adults. These multifunctional abilities are mainly attributed to the strain's mechanisms of producing metabolites, such as organic acids, soluble nutrients, and hydrolytic enzymes. [ABSTRACT FROM AUTHOR]

Leaf gas-exchange measurements are useful in assessing plant environmental responses. However, uncertainties in the leaf gas-exchange model potentially limit its application. The main challenge in the model-dependent calculations is to detect violations of assumptions. Here, we developed a system that integrates into one instrument the direct measurement of leaf intercellular CO2 concentration and the standard open-flow (OF) and novel open-diffusion (OD) systems for flux measurement. In the OD system, a gas-permeable membrane between the leaf ambient air and outside air creates CO2 and H2O differentials, rather than the air flow in the OF chamber. We measured hypostomatous and amphistomatous leaves of several species with different photosynthetic capacities [sunflower (Helianthus annuus), grape (Vitis vinifera), lemon (Citrus limon), and cherry (Prunus avium)]. The CO2 and H2O differentials in the OD system strictly depend on the flux measured by the OF system. The lower permeability of the membrane resulted in a larger differential per flux, indicating that the OD system can increase the resolution for a small flux. An analysis of the conductance model along with observations suggested that cuticle and leaf intercellular conductances and the unsaturation of leaf humidity contributed to discrepancies between the direct measurement and standard calculation. The combined system developed here provides an opportunity to address these overlooked concepts in leaf gas exchange. [ABSTRACT FROM AUTHOR]

Yeast is one of the important symbiotic flora in the insect gut. However, little is known about the gut yeast in Helicoverpa armigera (Lepidoptera: Noctuidae) under various dietary conditions. The composition and function of the intestinal yeast community also remain unclear. In this research, we explored the composition of yeast microorganisms in H. armigera larvae under different feeding environments, including apple, pear, tomato, artificial diet (laboratory feeding), Urtica fissa, Helianthus annuus, and Zinnia elegans (wild environment) using high-throughput sequencing. Results showed that a total of 43 yeast OTU readings were obtained, comprising 33 yeast genera and 42 yeast species. The yeast genera with a total content of more than 5% were Hanseniaspora (36.27%), Moesziomyces (21.47%), Trichosporon (16.20%), Wickerhamomyces (12.96%) and Pichia (6.38%). Hanseniaspora was predominant when fed indoors with fruits, whereas Moesziomyces was only detected in the wild group (Urtica fissa, Helianthus annuus, Zinnia elegans) and the artificial diet group. After transferring the larvae from artificial diet to apple, pear and tomato, the composition of intestinal yeast community changed, mainly reflected in the increased relative abundance of Hanseniaspora and the decreased abundance of Trichosporon. Simultaneously, the results of a diversity index indicated that the intestinal yeast microbial diversity of H. armigera fed on wild plants was higher than that of indoor artificial feeding. PCoA and PERMANOVA analysis concluded that there were significant differences in the gut yeast composition of H. armigera larvae on different diets. Our results confirmed that gut yeast communities of H. armigera can be influenced by host diets and may play an important role in host adaptation. [ABSTRACT FROM AUTHOR]

Broomrape (Orobanche cumana) negatively affects sunflower, causing severe yield losses, and thus, there is a need to control O. cumana infestation. Brassinosteroids (BRs) play key roles in plant growth and provide resilience to weed infection. This study aims to evaluate the mechanisms by which BRs ameliorate O. cumana infection in sunflower (Helianthus annuus). Seeds were pretreated with BRs (1, 10, and 100 nM) and O. cumana inoculation for 4 weeks under soil conditions. O. cumana infection significantly reduced plant growth traits, photosynthesis, endogenous BRs and regulated the plant defence (POX, GST), BRs signalling (BAK1, BSK1 to BSK4) and synthesis (BRI1, BR6OX2) genes. O. cumana also elevated the levels of malondialdehyde (MDA), hydroxyl radical (OH−), hydrogen peroxide (H2O2) and superoxide (O2•–) in leaves/roots by 77/112, 63/103, 56/97 and 54/89%, as well as caused ultrastructural cellular damages in both leaves and roots. In response, plants activated a few enzymes, superoxide dismutase (SOD), peroxidase (POD) and reduced glutathione but were unable to stimulate the activity of ascorbate peroxidase (APX) and catalase (CAT) enzymes. The addition of BRs (especially at 10 nM) notably recovered the ultrastructural cellular damages, lowered the production of oxidative stress, activated the key enzymatic antioxidants and induced the phenolic and lignin contents. The downregulation in the particular genes by BRs is attributed to the increased resilience of sunflower via a susceptible reaction. In a nutshell, BRs notably enhanced the sunflower resistance to O. cumana infection by escalating the plant immunity responses, inducing systemic acquired resistance, reducing oxidative or cellular damages, and modulating the expression of BR synthesis or signalling genes. [ABSTRACT FROM AUTHOR]

An extremely important oil crop in the world, Helianthus annuus L. is one of the world's most significant members of the Asteraceae family. The rate and extent of seed germination and agronomic features are consistently affecting by temperature (T) and changes in water potential (ψ). A broad hydrothermal time model with T and ψ components could explain sunflower responses over suboptimal T and ψ. A lab experiment was performed using the HTT model to discover both T and ψ and their interactive effects on sunflower germination and also to figure out the cardinal Ts values. The sunflower seeds were germinated at temperatures (15 °C, 20 °C, 25 °C and 30 °C); each Ts had five constant ψs of 0, 0.3, 0.6, 0.9, and 1.2 MPa via PEG 6000 as osmotic stress inducer. The results revealed that highest germination index was found in seed grown at 20 °C in distilled water (0 MPa) and the lowest at 30 °C with osmotic stress of (− 1.2 MPa). The highest value of germination rate index was found in seed grown at 20 °C in distilled water (0 MPa) and the lowest at 15 °C with an osmotic stress of (− 1.2 MPa). In conclusion, water potential, temperature, and their interactions have a considerable impact on seed germination rate, and other metrics (GI, SVI-I, GRI, GE, SVI-II, and MGT). Seeds sown at 20 °C with zero water potential showed high germination metrics such as GE, GP, GRI, and T50%. The maximum value to TTsub noted at 30 °C in − 0.9 MPa osmotic stress and the minimum value was calculated at 15 °C in − 1.2 MPa osmotic stress. The result of TTsupra recorded highest at 15 °C in controlled group (0 MPa). Moreover, θH was highest at 30 °C in controlled condition (0 MPa) and minimum value was observed at 20 °C under − 1.2 MPa osmotic stress. The value of θHTT were maximum at 30 °C in controlled group (0 MPa) and minimum value was recorded at 15 °C under − 1.2 MPa osmotic potential. The base, optimum and ceiling temperatures for sunflower germination metrics in this experiment were noted 6.8, 20 and 30 °C respectively. [ABSTRACT FROM AUTHOR]

The reason for this examination is today's wide usage of chlorophyll a fluorescence (ChlF) among researchers worldwide to measure photosynthetic efficiency. Although the instructions of the ChlF measuring device clearly emphasize the need for methodology adjustments, depending on the specific plant species, many researchers use the usual 30 min of dark adaptation before measurement. Namely, before any ChlF measurement, it is necessary to determine the specific duration of the leaf adaptation to the conditions of darkness of each plant tissue. Because of the numerous uses of the ChlF measurements, we decided to conduct this research to determine whether the appearance of the curves and parameter values depend on the time of sunflower leaf tissue adaptation to dark conditions. Therefore, this research aimed to examine the optimal adaptation time of sunflower tissue to dark conditions to obtain timely precise measurements and credible appearance of ChlF transient curves as well as accurate parameter values. The research was carried out on the sunflower hybrid Luka with 0, 15, 30, 45, 60, 75 and 90 min of dark adaptation in the vegetative, budding and flowering stages in the field conditions. According to the analyzed transient curves and parameters, it was determined that sunflower leaves should be kept in dark conditions for at least 15 min before the measurement of ChlF, which leads to the complete oxidation of PSII and the electron transport chain prior to a saturating pulse of light. [ABSTRACT FROM AUTHOR]

Sunflower (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. Core Ideas: Primed seeds demonstrated earlier and more synchronized germination.There are more differentially expressed genes (DEGs) during the early hours of priming than during the extended priming time.The DEGs are mostly associated with stress‐related responses and biosynthesis of metabolites, antioxidants, and phytohormones.The transcript level of the identified expansin genes confirmed its expression during seed priming, which is consistent with the transcriptome data.EXPA1, EXPA9, EXPA15, EXLA3, and EXP/Lol pI 3B GAG‐pre‐integrase domain are the possible markers for priming efficiency in sunflower seeds. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Helianthus annuus seed byproduct is a residual product obtained after seed oil extraction. The present study investigated the preventive and repair effects of the H. annuus seed byproduct ethanol extract (HSE) on ultraviolet radiation (UVR)‐induced injury in human immortalized keratinocytes (HaCaTs) and human skin fibroblasts (HSFs). Results revealed that the total phenolic acid and oligosaccharide content in HSE was >50%. HSE had a stronger preventive effect on UVR‐induced injury than the repair effect. Moreover, phenolic acids were the main active component of HSE mediating the preventative effect. In HaCaTs and HSFs, HSE prevented UVR‐induced injury by inhibiting excessive ROS production. It reduced the secretion of tumor necrosis TNF‐α, IL‐1α, IL‐1β, IL‐6, and IL‐8 by inhibiting the level of ROS, thus reducing inflammation‐mediated injury to skin cells. In addition, HSE inhibited the expression of various mRNA kinases in the MAPK–ERK/p38/JNK pathway. This downregulated the expression of activator protein‐1 (AP‐1) mRNA and further reduced the secretion of matrix metalloproteinase (MMP)‐1, MMP‐3, and MMP‐9 as well as reduced UVR‐induced injury to the cells. In conclusion, HSE is a broad‐spectrum, natural UV filter with high efficiency and low toxicity that has the potential to be used in sunscreen products. [ABSTRACT FROM AUTHOR]

Sunflower (Helianthus annuus L.) is a widely cultivated, fast-growing crop known for its seeds and oil, with substantial ecological and economic importance globally. However, it faces challenges from leaf diseases caused by Alternaria species, which threaten its yield. Three small-spored Alternaria species were isolated from leaf spot and blight symptoms on sunflower in Myanmar. All the species were determined based on morphological characterization and a multi-locus phylogenetic assessment of seven genes, including the internal transcribed spacer of rDNA region (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), RNA polymerase second largest subunit (RPB2), translation elongation factor 1-α (TEF1), Alternaria major allergen gene (Alt a 1), endopolygalacturonase gene (EndoPG), and an anonymous gene region (OPA10-2). The results introduced two new Alternaria species, A. myanmarensis sp. nov. and A. yamethinensis sp. nov., and a known species of A. burnsii, firstly reported from sunflower. [ABSTRACT FROM AUTHOR]

MYBs constitute the second largest transcription factor (TF) superfamily in flowering plants with substantial structural and functional diversity, which have been brought into focus because they affect flower colors by regulating anthocyanin biosynthesis. Up to now, the genomic data of several Chrysanthemum species have been released, which provides us with abundant genomic resources for revealing the evolution of the MYB gene family in Chrysanthemum species. In the present study, comparative analyses of the MYB gene family in six representative species, including C. lavandulifolium, C. seticuspe, C. ×morifolium, Helianthus annuus, Lactuca sativa, and Arabidopsis thaliana, were performed. A total of 1104 MYBs, which were classified into four subfamilies and 35 lineages, were identified in the three Chrysanthemum species (C. lavandulifolium, C. seticuspe, and C. ×morifolium). We found that whole-genome duplication and tandem duplication are the main duplication mechanisms that drove the occurrence of duplicates in CmMYBs (particularly in the R2R3-MYB subfamily) during the evolution of the cultivated chrysanthemums. Sequence structure and selective pressure analyses of the MYB gene family revealed that some of R2R3-MYBs were subjected to positive selection, which are mostly located on the distal telomere segments of the chromosomes and contain motifs 7 and 8. In addition, the gene expression analysis of CmMYBs in different organs and at various capitulum developmental stages of C. ×morifolium indicated that CmMYBS2, CmMYB96, and CmMYB109 might be the negative regulators for anthocyanin biosynthesis. Our results provide the phylogenetic context for research on the genetic and functional evolution of the MYB gene family in Chrysanthemum species and deepen our understanding of the regulatory mechanism of MYB TFs on the flower color of C. ×morifolium. [ABSTRACT FROM AUTHOR]

• Sunflower hybrids showed high tolerance to cadmium, with slight changes in growth. • Glutathione is probably involved in plant defence via synthesis of phytochelatins. • Cadmium accumulation depends on plant organ, genotype and metal dose. • Sunflowers are suitable for the phytostabilisation of cadmium-contaminated soils. • Better remediation potential of plants can be expected at lower cadmium doses. 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. [ABSTRACT FROM AUTHOR]

• Continuous effluents and wastewater discharge contaminants the soil in the vicinity of Lyari River, Karachi. • Helianthus annuus, Zea mays and Brassica juncea plants successfully grown in the heavy metals contaminated soil. • Z. mays exhibited the higher tolerance against HMCS (based on growth attributes). • H. annuus was the best hyper accumulator plant related to other tested crops. • The physiological and biochemical attributes of plant are summarized and discussed. • Perspectives are presented for the potentials of pytoremediation in sustainable agriculture. Industrial and domestic effluents are often disposed of untreated or undertreated in developing countries resulting in the deposition of heavy metals in soil and water bodies. Karachi is the largest commercial hub of the country with many industries and the densely developed urban area. Lyari is one of the two major rivers of Karachi which has become a dumping site of the city's effluent. In the present study three crops- Helianthus annuus, Zea mays and Brassica juncea were grown in the heavy metals contaminated soil (HMCS) of Lyari River to explore their tolerance and phytoremediation potential. All the tested plants exhibited improved germination and growth in HMCS. The shoot length and plant biomass of all three cultivated species were high in HMCS. However, the tolerance against HMCS (based on growth attributes) of Z. mays was higher than other crops. The photochemistry and relative chlorophyll content of all plants were unaffected with HMCS. Although, H 2 O 2 content was high (around 25 %) but no change in antioxidant enzyme was found in H. annuus and B. juncea species under HMCS. In contrast, the enhanced activity of peroxidase and catalase enzymes in the shoot of Z. mays along with no increase in H 2 O 2 content is related with better plant growth in HMCS. H. annuus and B. juncea accumulated 40 % more Cu in shoots that are associated with high BAF and TF. High Zn accumulation in root (20 % more than shoot) of three cultivated species is related with <1 TF. Higher accumulation (40 % more than control) of Fe in H. annuus and Z. mays is linked with their BAF values. Among tested heavy metals, Mn accumulation was least (< 19 mg Kg−1) in all species. This study concluded that, Zea mays could be used as a best hyper-tolerant plant while H. annuus as the best hyper accumulator. [ABSTRACT FROM AUTHOR]

Sunflower (Helianthus annuus L.) is an important, substantial global oil crop with robust resilience to drought and salt stresses. The TGA (TGACG motif-binding factor) transcription factors, belonging to the basic region leucine zipper (bZIP) family, have been implicated in orchestrating multiple biological processes. Despite their functional significance, a comprehensive investigation of the TGA family's abiotic stress tolerance in sunflowers remains elusive. In the present study, we identified 14 TGA proteins in the sunflower genome, which were unequally distributed across 17 chromosomes. Employing phylogenetic analysis encompassing 149 TGA members among 13 distinct species, we revealed the evolutionary conservation of TGA proteins across the plant kingdom. Collinearity analysis suggested that both HaTGA01 and HaTGA03 were generated due to HaTGA08 gene duplication. Notably, qRT-PCR analysis demonstrated that HaTGA04, HaTGA05, and HaTGA14 genes were remarkably upregulated under ABA, MeJA, and salt treatments, whereas HaTGA03, HaTGA06, and HaTGA07 were significantly repressed. This study contributes valuable perspectives on the potential roles of the HaTGA gene family under various stress conditions in sunflowers, thereby enhancing our understanding of TGA gene family dynamics and function within this agriculturally significant species. [ABSTRACT FROM AUTHOR]

The quantity and quality of sunflower oil are key factors for the crushing industry. This research presents a comprehensive analysis of the oil quality parameters of seven foreign sunflower hybrids grown in Morocco. Conducted over two consecutive years (2018 and 2019), the study focuses on key traits, including oil content, acidity index, peroxide index, refractive index, color index, total phenolic content, total flavonoid content, and antioxidant activity. Significant variations in most parameters, including color properties, were observed between the two years and among the seven varieties, indicating the influence of genetic and environmental factors. This highlights the importance of understanding the genetic potential of sunflower hybrids and the impact of environmental variables on oil quality. More favorable weather conditions in 2019, compared to 2018, contributed to better oil quality in all the varieties investigated. Overall, four homogeneous groups of hybrid varieties were identified based on oil content and other biochemical parameters. Some of these hybrids, like 'Niagara', had moderate oil content but high polyphenol content, flavonoid content and antioxidant activity, as well as a lower peroxide index, making them potential sources of natural antioxidant compounds as well as dietary supplements. Overall, this research provides sunflower breeders with valuable insights into the development of new high-performing hybrids with enhanced oil quality that could be used to produce functional foods with health benefits. These findings have implications for the use of seed oils from those hybrids in various industries and underscore the importance of further and more in-depth research on sunflower oil quality in the context of climate change. [ABSTRACT FROM AUTHOR]

Background: Arsenic (As) is a highly toxic and carcinogenic pollutant commonly found in soil and water, posing significant risks to human health and plant growth. Objective: The objectives of this study to evaluate morphological, biochemical, and physiological markers, as well as ion homeostasis, to alleviate the toxic effects of As in sunflowers through the exogenous application of salicylic acid (SA), γ-aminobutyric acid (GABA), and their combination. Methods: A pot experiment was conducted using two sunflower genotypes, FH-779 and FH-773, subjected to As stress (60 mg kg−1) to evaluate the effects of SA at 100 mg L−1, GABA at 200 mg L−1, and their combination on growth and related physiological and biochemical attributes under As stress. Results: The study revealed that As toxicity had a detrimental effect on various growth parameters, chlorophyll pigments, relative water content, total proteins, and nutrient uptake in sunflower plants. It also led to increased oxidative stress, as indicated by higher levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2), along with As accumulation in the roots and leaves. However, the application of SA and GABA protected against As-induced damage by enhancing the enzymatic antioxidant defense system. This was achieved through the activation of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities, as well as an increase in osmolytes. They also improved nutrient acquisition and plant growth under As toxicity. Conclusions: We investigated the regulatory roles of SA and GABA in mitigating arsenic-induced phytotoxic effects on sunflower. Our results revealed a significant interaction between SA and GABA in regulating growth, photosynthesis, metabolites, antioxidant defense systems, and nutrient uptake in sunflower under As stress. These findings provide valuable insights into plant defense mechanisms and strategies to enhance stress tolerance in contaminated environments. In the future, SA and GABA could be valuable tools for managing stress in other important crops facing abiotic stress conditions. [ABSTRACT FROM AUTHOR]

This study investigates the impact of soaking, germination, and roasting under various conditions on the phenolic content, antioxidant activities, and fatty acid profile of sunflower seeds of striped and black oil seed varieties. Ferulic acid emerged as the predominant phenolic acid across all samples. The study highlights the influence of different treatments and processing conditions on the levels of phenolic acids and flavonoids. Results revealed that soaking striped seeds for 24 h and roasting black oil seeds for 6 min exhibited the highest total phenolic content (TPC) and total flavonoid content (TFC). Antioxidant activities varied, with striped seeds soaked for 24 h demonstrating the highest ferric-reducing antioxidant power (FRAP) values, while black oil seeds roasted for 6 min exhibited superior 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity. Oleic acid and linoleic acid were identified as major fatty acids in all processed samples, with striped seeds germinated for 24 h and black oil seeds germinated for 48 h displaying the highest concentrations. Soaking led to a reduction in both unsaturated and saturated fatty acids in both varieties. Roasting further influenced fatty acid concentrations, with a significant increase in striped seeds after 5 and 6 h of roasting, followed by a gradual decrease. Our findings suggest that incorporating appropriate processing methods, such as soaking striped seeds for 24 h and roasting black oil seeds for 6 min, enhances the potential health benefits of sunflower seeds. [ABSTRACT FROM AUTHOR]

Cultivated crops are generally expected to have less abiotic stress tolerance than their wild relatives. However, this assumption is not well supported by empirical literature and may depend on the type of stress and how it is imposed, as well as the measure of tolerance being used. Here, we investigated whether wild and cultivated accessions of Helianthus annuus differed in stress tolerance assessed as proportional decline in biomass due to drought and whether wild and cultivated accessions differed in trait responses to drought and trait associations with tolerance. In a greenhouse study, H. annuus accessions in the two domestication classes (eight cultivated and eight wild accessions) received two treatments: a well‐watered control and a moderate drought implemented as a dry down followed by maintenance at a predetermined soil moisture level with automated irrigation. Treatments were imposed at the seedling stage, and plants were harvested after 2 weeks of treatment. The proportional biomass decline in response to drought was 24% for cultivated H. annuus accessions but was not significant for the wild accessions. Thus, using the metric of proportional biomass decline, the cultivated accessions had less drought tolerance. Among accessions, there was no tradeoff between drought tolerance and vigor assessed as biomass in the control treatment. In a multivariate analysis, wild and cultivated accessions did not differ from each other or in response to drought for a subset of morphological, physiological, and allocational traits. Analyzed individually, traits varied in response to drought in wild and/or cultivated accessions, including declines in specific leaf area, leaf theoretical maximum stomatal conductance (gsmax), and stomatal pore length, but there was no treatment response for stomatal density, succulence, or the ability to osmotically adjust. Focusing on traits associations with tolerance, plasticity in gsmax was the most interesting because its association with tolerance differed by domestication class (although the effects were relatively weak) and thus might contribute to lower tolerance of cultivated sunflower. Our H. annuus results support the expectation that stress tolerance is lower in crops than wild relatives under some conditions. However, determining the key traits that underpin differences in moderate drought tolerance between wild and cultivated H. annuus remains elusive. [ABSTRACT FROM AUTHOR]

Background: Drought severely limits sunflower production especially at the seedling stage. To investigate the response mechanism of sunflowers to drought stress, we utilized two genotypes of sunflower materials with different drought resistances as test materials. The physiological responses were investigated under well-watered (0 h) and drought-stressed conditions (24 h, 48 h, and 72 h). Results: ANOVA revealed the greatest differences in physiological indices between 72 h of drought stress and 0 h of drought stress. Transcriptome analysis was performed after 72 h of drought stress. At 0 h, there were 7482 and 5627 differentially expressed genes (DEGs) in the leaves of K55 and K58, respectively, and 2150 and 2527 DEGs in the roots of K55 and K58, respectively. A total of 870 transcription factors (TFs) were identified among theDEGs, among which the high-abundance TF families included AP2/ERF, MYB, bHLH,and WRKY. Five modules were screened using weighted gene coexpressionnetwork analysis (WGCNA), three and two of which were positively and negatively, respectively, related to physiological traits. KEGG analysis revealedthat under drought stress, "photosynthesis", "carotenoid biosynthesis", "starch and sucrose metabolism", "ribosome", "carotenoid biosynthesis", "starch and sucrose metabolism", "protein phosphorylation" and "phytohormone signaling" are six important metabolic pathways involved in the response of sunflower to drought stress. Cytoscape software was used to visualize the three key modules, and the hub genes were screened. Finally, a total of 99 important candidate genes that may be associated with the drought response in sunflower plants were obtained, and the homology of these genes was compared with that in Arabidopsis thaliana. Conclusions: Taken together, our findings could lead to a better understanding of drought tolerance in sunflowers and facilitate the selection of drought-tolerant sunflower varieties. [ABSTRACT FROM AUTHOR]

Plant protein phosphatase 2C (PP2C) plays vital roles in responding to various stresses, stimulating growth factors, phytohormones, and metabolic activities in many important plant species. However, the PP2C gene family has not been investigated in the economically valuable plant species sunflower (Helianthus annuus L.). This study used comprehensive bioinformatics tools to identify and characterize the PP2C gene family members in the sunflower genome (H. annuus r1.2). Additionally, we analyzed the expression profiles of these genes using RNA-seq data under four different stress conditions in both leaf and root tissues. A total of 121 PP2C genes were identified in the sunflower genome distributed unevenly across the 17 chromosomes, all containing the Type-2C phosphatase domain. HanPP2C genes are divided into 15 subgroups (A-L) based on phylogenetic tree analysis. Analyses of conserved domains, gene structures, and motifs revealed higher structural and functional similarities within various subgroups. Gene duplication and collinearity analysis showed that among the 53 HanPP2C gene pairs, 48 demonstrated segmental duplications under strong purifying selection pressure, with only five gene pairs showing tandem duplications. The abundant segmental duplication was observed compared to tandem duplication, which was the major factor underlying the dispersion of the PP2C gene family in sunflowers. Most HanPP2C proteins were localized in the nucleus, cytoplasm, and chloroplast. Among the 121 HanPP2C genes, we identified 71 miRNAs targeting 86 HanPP2C genes involved in plant developmental processes and response to abiotic stresses. By analyzing cis-elements, we identified 63 cis-regulatory elements in the promoter regions of HanPP2C genes associated with light responsiveness, tissue-specificity, phytohormone, and stress responses. Based on RNA-seq data from two sunflower tissues (leaf and root), 47 HanPP2C genes exhibited varying expression levels in leaf tissue, while 49 HanPP2C genes showed differential expression patterns in root tissue across all stress conditions. Transcriptome profiling revealed that nine HanPP2C genes (HanPP2C12, HanPP2C36, HanPP2C38, HanPP2C47, HanPP2C48, HanPP2C53, HanPP2C54, HanPP2C59, and HanPP2C73) exhibited higher expression in leaf tissue, and five HanPP2C genes (HanPP2C13, HanPP2C47, HanPP2C48, HanPP2C54, and HanPP2C95) showed enhanced expression in root tissue in response to the four stress treatments, compared to the control conditions. These results suggest that these HanPP2C genes may be potential candidates for conferring tolerance to multiple stresses and further detailed characterization to elucidate their functions. From these candidates, 3D structures were predicted for six HanPP2C proteins (HanPP2C47, HanPP2C48, HanPP2C53, HanPP2C54, HanPP2C59, and HanPP2C73), which provided satisfactory models. Our findings provide valuable insights into the PP2C gene family in the sunflower genome, which could play a crucial role in responding to various stresses. This information can be exploited in sunflower breeding programs to develop improved cultivars with increased abiotic stress tolerance. [ABSTRACT FROM AUTHOR]

• Exogenous IAA (25 µM) and/or H 2 O 2 (350 µM) regulates seedling growth, Na+/K+ homeostasis, and H 2 S metabolism in etiolated sunflower seedlings. • Exogenous auxin (IAA) and/or H 2 O 2 treatment recovered both root length and lateral root proliferation under NaCl stress (120 mM). • IAA and H 2 O 2 modules H 2 S content in seedling roots and cotyledons and impact l -DES activity. • TIBA disrupts the internal auxin gradient in roots and reverse the positive effects of exogenous IAA. Although H 2 S has been reported to modulate auxin and H 2 O 2 signaling during abiotic stress, no reports decipher the interactive roles of exogenous auxin and H 2 O 2 on the regulation of endogenous H 2 S homeostasis. In the present work, auxin (IAA) and hydrogen peroxide (H 2 O 2) interaction appear to be crucial in regulating Na+/K+ homeostasis, recovery in seedling growth and H 2 S accumulation in NaCl-stressed sunflower seedlings. Interestingly, impairment in endogenous IAA transport (TIBA application) also impacts H 2 S accumulation in the roots and cotyledons. IAA supplementation is effective in reducing Na+/K+ ratio and electrolytic leakage in roots, which reverses in the presence of TIBA (polar auxin transport inhibitor) application. IAA and H 2 O 2 -mediated modulation of H 2 S content corroborates with l -DES activity in seedling roots and cotyledons. In contrast to cotyledons, roots exhibited a reduction in H 2 S content in the presence of treatments (IAA and H 2 O 2). H 2 O 2 supplementation seems to partially circumvent the changes caused by the disruption of auxin transport. Thus, we hypothesize that auxin might imply H 2 O 2 as a crucial signaling component in the regulation of H 2 S levels in sunflower tissues. To sum up, IAA and H 2 O 2 interaction regulates root growth, LR proliferation, Na+/K+ ratio, and H 2 S metabolism in sunflower seedling roots. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The work aimed to assess the restoration of metal-contaminated soil pH and EC and impacts on Cd accumulation in plants Helianthus annuus (Sunflower) through tea waste in a natural environment. Various doses of Cd metal treatment (1–5 ppm) were provided to the soil with two sets of organic matter (tea waste) in a dry and wet state. The soil and plants were analyzed using analytical procedures like AAS, SEM and EDS, while pH and EC were measured through pH and conductivity meter. The mitigating effect of tea waste was observed on the pH (6.2–6.9) and EC of the soil, which was reflected by the healthy growth of the plants. It was established that the movement of the Cd was successfully controlled with the restoration of essential nutrient elements in different parts of plants. It was strongly related to recovered soil pH and EC in two sets of tested H. annuus plant species. The healthy growth of the plants showed that tea waste acts as a safe, harmless and sound remediator of soil, which enhances the soil nutrient ionic activity from soil to roots of the plants in the presence of the Cd metal, effective for the use of agriculture purposes. [ABSTRACT FROM AUTHOR]

Pirate bugs of the genus Orius are efficient predators of economically important agricultural pests. However, intensification of agriculture reduced their populations globally. The aim of the study was to use a phylogenetic approach to determine which Orius spp. were associated with inflorescences of ornamental sunflower (Helianthus annuus L.) at Toluca, Mexico State. Specimens collected were identified by PCR amplification and sequencing of the partial cytochrome c oxidase I (cox1) gene using primers LCO 1492 and HCO 2198. The phylogenetic reconstruction was made using Bayesian analyses including sequences obtained in the study and sequences previously published for Orius spp. Molecular analyses identified specimens collected from sunflower inflorescences at Toluca as Orius tristicolor White. The study suggested the sunflower plant could be used to attract or maintain the predator in ornamental and vegetable crops in the region, as well as establish conservation niches to use in integrated pest management programs. Las chinches piratas del género Orius son depredadores eficientes de plagas agrícolas económicamente importantes. Sin embargo, la intensificación de la agricultura ha reducido su población a nivel mundial. El objetivo del estudio fue determinar las especies del género Orius asociadas con las inflorescencias de girasol ornamental en Toluca, México, utilizando un enfoque filogenético. Los especímenes recolectados fueron identificados mediante la amplificación por PCR y secuenciación parcial del gen citocromo c oxidasa I (cox1) utilizando los iniciadores LCO 1492 y HCO 2198. La reconstrucción filogenética se realizó con análisis bayesianos, incluyendo las secuencias obtenidas en el presente estudio junto con secuencias publicadas para Orius spp. Los análisis moleculares identificaron a los especímenes recolectados en inflorescencias de girasol en Toluca como Orius tristicolor White. Este estudio sugiere que la planta de girasol podría utilizarse para atraer o mantener este depredador en los cultivos ornamentales y vegetales de la región, así como para establecer nichos de conservación e incorporarlos en programas de manejo integrado. [ABSTRACT FROM AUTHOR]

Specialty cut flowers are in demand, especially in the domestic market as they can be grown with low production costs without the need for specially equipped greenhouses and offer diversity in terms of form, texture, and colour. These products, which are widely cultivated in the USA, are not well known in Türkiye. One of the main problems of the Turkish cut flower sector is its dependence on foreign inputs and the lack of product diversity. Therefore, specialty cut flower production can be an alternative crop for Türkiye, which has climatic advantages. The cut flower potential of plants such as Zinnia elegans, Tagates erecta, Helianthus annuus, Gomphrena globosa, Centaurea cyanus, and Cleome spinosa that are commonly grown in gardens has been evaluated. After harvesting these flowers grown in an open field in June-October 2020, the stem length (cm), stem thickness (mm), flower length (cm), flower diameter (cm), flower weight (g), and vase life (days) were measured. As a result of the evaluations, considering the phenological findings such as flowering and harvesting period, Zinnia elegans, Tagates erecta, Helianthus annuus, Gomphrena globosa, and Centaurea cyanus were found to be suitable for Eskişehir climatic conditions due to their long flowering periods. On the other hand, if the stem length value, which is one of the most important parameters for cut flowers, is taken as a reference, the minimum stem length value of 30 cm and above is met by Zinnia elegans, Tagates erecta, Helianthus annuus, and Cleome spinosa while the vase life value of 6 days and above is met by Zinnia elegans, Tagates erecta, Helianthus annuus, Gomphrena globosa, and Cleome spinosa. However, Cleome spinosa was not found to be suitable for the region due to its low yield value and short flowering period, while Zinnia elegans, Helianthus annuus, Tagates erecta, and Gomphrena globosa were found to be plants that could be evaluated for the region. In addition, it is believed that the cultivation of specialty cut flowers, with the selection of suitable species, will be an alternative production in regions without climatic advantages. [ABSTRACT FROM AUTHOR]

In the study on the diversity of pollinators and their pollination efficiency in sunflower (Helianthus annuus L.) under field condition of Odisha during 2021-22, recorded 18 species of pollinators. Indian honeybee, Apis cerana indica F. (Hymenoptera, Apidae) was found to be the major one among the insect pollinators. The experiment conducted for two years with three different treatments viz., open pollination (OP), managed A. cerana indica pollination (HB) and pollinator exclusion (PE) for better yield and quality revealed that both quantitative and qualitative parameters were significantly higher in OP sunflower crops followed by crops pollinated by A. cerana indica. Significantly higher seed yield, 1000 seed weight, percentage of seed filling and number of seed per capitulum were recorded in these treatments. These findings indicate OP and HB increase 33 per cent more yield in sunflower. [ABSTRACT FROM AUTHOR]