Response Of Sunflower Research Articles

Sunflower response to nitrogen doses

The sunflower is an oilseed species, rustic, cultivated in different agroecosystems. The responses of cultivars to nitrogen fertilization vary according to the cultivar and environment. Therefore, this research aimed to evaluate the response of biometric characters of sunflower cv. Embrapa 122-V2000 under N doses. The experiment was carried out in a randomized block design with five treatments (0, 40, 80, 120 and 160 kg N ha-1) and four blocks. All characters were influenced (p<0.05) by N doses, fitting to the quadratic model. The maximum values of plant height (1.68 m), stem diameter (22.71 mm), leaf area (423.41 cm2), capitulum diameter (15.22 cm), dry biomass yield (6,075.13 kg DM ha-1) and grains (2,982.89 kg ha-1), N use efficiency from biomass (80.3 kg kg-1) and grains (43.27 kg kg-1) close to 90 kg N ha-1, this dose being recommended for the edaphoclimatic conditions of the Agreste Meridional Region of Pernambuco, Brazil.

Phytoextraction Potential of Sunn Hemp, Sunflower, and Marigold for Carbaryl Contamination: Hydroponic Experiment.

The phytoextraction ability and responses of sunn hemp, sunflower, and marigold plants were investigated toward carbaryl insecticide at 10 mg L-1 and its degradative product (1-naphthol). All test plants exhibited significant carbaryl removal capability (65-93%) with different mechanisms. Marigold had the highest translocation factor, with carbaryl taken up, translocated and accumulated in the shoots, where it was biotransformed into 1-naphthol. Consequently, marigold had the least observable toxicity symptoms caused by carbaryl and the highest bioconcentration factor (1848), indicating its hyperaccumulating capability. Sunflower responded to carbaryl exposure differently, with the highest carbaryl accumulation (8.7 mg kg-1) in roots within 4 days of cultivation, leading to a partial toxicity effect. Sunn hemp exhibited severe toxicity, having the highest carbaryl accumulation (91.7 mg kg-1) that was biotransformed to 1-naphthol in the sunn hemp shoots. In addition, the different models were discussed on plant hormone formation in response to carbaryl exposure.

Phenotypic and transcriptomic responses of cultivated sunflower seedlings (Helianthus annuus L.) to four abiotic stresses

Plants encounter and respond to numerous abiotic stresses during their lifetimes. These stresses are often related and could therefore elicit related responses. There are, however, relatively few detailed comparisons between multiple different stresses at the molecular level. Here, we investigated the phenotypic and transcriptomic response of cultivated sunflower (Helianthus annuus L.) seedlings to three water-related stresses (i.e., dry-down, an osmotic challenge, and salt stress), as well as a generalized low-nutrient stress. All four stresses negatively impacted seedling growth, with the nutrient stress having a more divergent response from control as compared to the water-related stresses. Phenotypic responses were consistent with expectations for growth in low-resource environments, including increased (i.e., less negative) carbon fractionation values and leaf C:N ratios, as well as increased belowground biomass allocation. The number of differentially expressed genes (DEGs) under stress was greater in leaf tissue, but roots exhibited a higher proportion of DEGs unique to individual stresses. Overall, the three water-related stresses had a more similar transcriptomic response to each other vs. nutrient stress, though this pattern was more pronounced in root vs. leaf tissue. In contrast to our DEG analyses, co-expression network analysis revealed that there was little indication of a shared response between the four stresses in despite the majority of DEGs being shared between multiple stresses. Importantly, osmotic stress, which is often used to simulate drought stress in experimental settings, had little transcriptomic resemblance to true water limitation (i.e., dry-down) in our study, calling into question its utility as a means for simulating drought.

Efficiency of Nitrogen Use in Sunflower.

The large variation in the response of sunflower to nitrogen fertilization indicates the need for studies to better adjust the optimum levels of this nutrient for production conditions. Our objectives were to analyze the agronomic yield of sunflower cultivars as a function of nitrogen fertilization; indicate the cultivar with high nitrogen use efficiency; and measure the adequate N dose for sunflower through nutritional efficiency. The completely randomized block design with split plots was used to conduct the experiments. The treatments included five nitrogen rates being allocated in the plots and the four sunflower cultivars. To estimate the nutrient use efficiency in the sunflower, we measured agronomic efficiency (AE), physiological efficiency (PE), agrophysiological efficiency (APE), apparent recovery efficiency (ARE), and utilization efficiency (UE). The results indicate that all cultivars had a reduction in AE due to the increase in N doses in the first crop. For PE, the highest values were observed for Altis 99 during the 2016 harvest. In that same harvest, Altis 99 had the highest APE. The dose of 30 kg ha−1 provided greater ARE for all cultivars in both crops, with greater emphasis on BRS 122 and Altis 99. The cultivation of cultivars Altis 99 and Multissol at a dose of 30 kg ha−1 in is recommended semiarid regions.

Agronomic response of sunflower subjected to biochar and arbuscular mycorrhizal fungi application under drought conditions

There is growing interest in developing environment-friendly farming practices that can limit the impact of drought stress in agriculture. The main objective of this study was to investigate the combined effects of biochar and arbuscular mycorrhizal fungi (AMF) on the agronomic responses of sunflower. Field experiments were conducted in the 2018 and 2019 growing seasons in semi-arid environments of Iran. The following treatments were adopted: i) three levels of biochar [0, 2.5 and 5 t ha–1 of biochar called Bl, Bm and Bh, respectively]; and ii) three irrigation levels (50, 30 and 10% of the maximum available water (MAW) called 50MAW, 30MAW and 10MAW, respectively)]; iii) two levels of AMF inoculation (with and without the addition of AMF called +AMF and –AMF, respectively). The experimental design was a randomized complete block design. At flowering, the leaf area index (LAI) was generally higher in the plants subjected to Bh-+AMF (on average 4.95), even if the LAI values changed according to biochar application (Bh > Bm > Bl) and the level of irrigation (50MAW > 30MAW > 10MAW). At harvesting, sunflower seed yield was highest in +AMF and in Bh (on average 53.9 and 51.2 g plants–1, respectively). Sunflower plants subjected to Bh-+AMF showed the highest seed yield under all irrigation levels (79.4, 57.1 and 32.3 g plant–1 in 50MAW, 30MAW and 10MAW, respectively). The application of biochar combined with AMF resulted in an increase in agronomic responses compared to untreated plants (Bl- –AMF) such as root biomass (+15%), stem diameter (+12%), plant height (+5%) and head diameter (+15%). Seed protein was higher in +AMF than –AMF (on average 20.7 vs 17.2 g m–2, respectively) and in Bh and Bm compared with Bl (on average 19.4 vs 18.2 g m–2, respectively). The oil content of seeds was affected by biochar application and AMF inoculation, especially under 50MAW and 30MAW irrigation levels; conversely, no differences were observed under the 10MAW irrigation level. Sunflower yield characteristics were positively correlated to the net photosynthesis rate and negatively affected by hydrogen peroxide and malondialdehyde content. The results showed that the adoption of biochar and AMF may represent as a successful strategy to balance crop productivity in a semi-arid environment. Although further research is required for a better understanding of the irrigation and fertilization schedule, these preliminary results could be extended to other crops which have similar requirements to sunflower. Highlights - The combined effects of biochar and arbuscular mycorrhizal fungi on sunflower are studied. - Biochar application and mycorrhiza inoculation improved plant performance. - Biochar and AMF positively affected the net photosynthesis rate of sunflower plants. - The adoption of biochar and AMF may mitigate the effect of drought conditions. - Biochar and AMF can support sunflower cultivation.

Response of sunflower and soybean to infection with Sclerotinia sclerotiorum with addition of organic amendments

The addition of compost, green waste biochar, and wood biochar to a pathosystem consisting of Sclerotinia sclerotiorum (Lib.) de Bary and two susceptible host plants, sunflower (Helianthus annuus L.) and soybean (Glycine max L.), was investigated in a greenhouse study. Plant growth characteristics, disease incidence and the mycelial growth of S. sclerotiorum in root exudates of plants inoculated and not inoculated with this pathogen were determined. Both plants showed different responses in terms of shoot and root weight. Disease incidence in sunflower was lowest in the substrate consisting of green waste biochar and compost. The disease incidence in this substrate was approximately half that in the control treatment. In soybean, the highest disease suppression was achieved with this combined substrate too. Mycelial growth in sunflower root exudates from uninoculated plants was higher than that in sunflower plants inoculated with S. sclerotiorum. The substrate did not influence mycelial growth in root exudates. Soybean root exudates did not show this effect of the pathogen. This study proves that the addition of organic matter inputs such as biochar and compost can improve plant growth and can also have favorable effects against S. sclerotiorum infection. In addition, it is demonstrated that both the pathogen and host plant are instrumental in determining the mode of action of the supplemented organic material. The addition of the same organic material can lead to different responses in certain pathogens, such as S. sclerotiorum, depending on the host plant.

Growth and yield responses of sunflower to drainage in waterlogged saline soil are caused by changes in plant-water relations and ion concentrations in leaves

PurposeWhile well-designed drainage systems could improve crop growth and yield by mitigating waterlogging and salinity stresses, field evidence of the yield responses to changes in plant-water relations and ion concentrations in leaves is scarce. We investigated the changes in ion concentrations in leaves and plant-water relations of sunflower caused by drainage in waterlogged saline soil, and their relationships to growth and yield.MethodsOver two growing seasons, we tested four drainage treatments: undrained, surface drains (SD; 0.1 m deep, 1.8 m apart), subsoil drains (SSD; 0.5 m deep, 4.5 m apart) and SSD + SD. All plots were inundated (2–3 cm depth; water salinity, ECw, 1.5–2.5 dS m–1) for 24 h at vegetative emergence and at the 8-leaf stage before opening drains.ResultsRelative to the most drained treatment (SSD + SD), the undrained treatment caused higher waterlogging at 0–30 cm depth, and decreased solute potential (Ψs) of soil at 7.5 cm to 52–374 kPa, leaf K+ by 5–20%, stomatal conductance by 5–37% and leaf greenness by 12–25%, but increased leaf Na+ by 25–70%, Na+/K+ ratio by 38–100% and leaf water potential by 90–250 kPa throughout the cropping season; these changes were closely related to reduced growth and yield.ConclusionsThe improved yield from the combination of shallow surface and sub-surface drains was attributed to an alleviation of salinity-waterlogging stress early in the season and to increased soil water late in the season that increased Ψs and decreased Na+/K+ ratio in leaves.

Synthesis and Characterization of Nano-Sulfur and Its Impact on Growth, Yield, and Quality of Sunflower (Helianthus annuus L.)

ABSTRACT A laboratory study was undertaken to determine the response of sunflower to nano-sulfur application in comparison to conventional sulfatic fertilizer. Nano-sulfur particles were characterized using a particle size analyzer, zeta potential, UV-Spectroscopy, XRD, FT-IR, SEM, and TEM. After the complete characterization, the sulfur release pattern was studied in a percolation reactor system. Thereafter, response studies were carried out using sunflower (var. KBSH 42) crop. The stable and uniform nano-sulfur particles with a medium diameter of 35–45 nm are yielded by the aqueous precipitation method. The results showed that sulfur release from the nano-sulfur has prolonged for 42 days, while the sulfur release from the ordinary sulfur fertilizer (gypsum) ceased to exist within 35 days. Nano-sulfur fertilized plants had registered significantly higher dry matter production (11–12%), seed yield (15%), and oil content (14.7%) than gypsum fertilized plants. The data revealed that nano-sulfur assists in improving the available sulfur in soils.

Literature Study Of The Ability Of Fragrant Roots (Vetiveria zizanioides) And Sunflowers (Helianthus Annuus) On Phytoremediation Of Lead-Tainted Soil (Pb)

Lead pollution is a serious problem because of its wide distribution as a result of residential, agricultural, and industrial activities. Lead is a heavy metal that can cause various health problems due to its high toxicity. The high level of lead pollution needs to be overcome to reduce the impact of the risk of lead toxicity, one of which is phytoremediation. The ability of vetiver and sunflower in the phytoremediation process of lead has been reported by various literature. 40 kinds of literature were used as data sources. A literature review by making identification and classification based on the variables and parameters that will be reviewed from several articles that discuss the same topic using a synthetic matrix. Both plants have hyperaccumulator properties in absorbing heavy metals. The highest accumulation of Pb was in the roots up to 5500 mg kg-1, while sunflowers accumulated Pb up to 1450 mg kg-1. The accumulation of Pb was influenced by soil type, nutrient abundance, rhizobacteria, and chelating agents. The toxicity of highly contaminated metals did not significantly affect the growth of vetiver but only slightly decreased parameters. Sunflower response to stress caused by Pb varies depending on variety, soil type, metal type, dose, and duration of metal exposure

Literature Study Of The Ability Of Fragrant Roots (Vetiveria zizanioides) And Sunflowers (Helianthus Annuus) On Phytoremediation Of Lead-Tainted Soil (Pb)

Lead pollution is a serious problem because of its wide distribution as a result of residential, agricultural, and industrial activities. Lead is a heavy metal that can cause various health problems due to its high toxicity. The high level of lead pollution needs to be overcome to reduce the impact of the risk of lead toxicity, one of which is phytoremediation. The ability of vetiver and sunflower in the phytoremediation process of lead has been reported by various literature. 40 kinds of literature were used as data sources. A literature review by making identification and classification based on the variables and parameters that will be reviewed from several articles that discuss the same topic using a synthetic matrix. Both plants have hyperaccumulator properties in absorbing heavy metals. The highest accumulation of Pb was in the roots up to 5500 mg kg-1, while sunflowers accumulated Pb up to 1450 mg kg-1. The accumulation of Pb was influenced by soil type, nutrient abundance, rhizobacteria, and chelating agents. The toxicity of highly contaminated metals did not significantly affect the growth of vetiver but only slightly decreased parameters. Sunflower response to stress caused by Pb varies depending on variety, soil type, metal type, dose, and duration of metal exposure

Crop response and water productivity of sunflower (Helianthus annuus L.) drip-irrigated with magnetically treated and non-magnetically treated water with variable salinity

To compare the effect of magnetic drip irrigation and conventional irrigation with different salinity levels on water productivity and yield of sunflower (Helianthus annuus L.), a factorial experiment was conducted using a completely randomized design with 6 treatments and 3 replicates at the Research Station of the Faculty of Water Sciences Engineering, Shahid Chamran University of Ahvaz, Iran. The experiment was executed over the crop year 2018–19. The treatment variables consisted of 2 types of water (magnetically treated and non-magnetically treated) and 3 salinity levels (Karun River water (S1), 4 dS/m (S2), and 6 dS/m (S3)). The use of magnetically treated irrigation water increased the biomass water use efficiency, and the weight of 100 seeds by 13.9%, and 5.48%, respectively. With the conventional irrigation method, increased salinity reduced the seed yield. The highest seed yield and irrigation water productivity were observed at 4 459 kg/ha and 0.73 kg/m3 for grain yield at a water salinity level of S1 (the control treatment). The application of water with salinity of 4 dS/m and 6 dS/m (S2 and S3) caused a reduction in seed yield by 9.3 and 21.8%, respectively, in comparison to that of the control treatment. Moreover, irrigation water productivity for the biomass yield decreased by 14.57 and 29.23%, respectively. Based on the results of this study, the use of magnetically treated water can reduce the effects of salinity stress under conditions of salt stress. Therefore, magnetically treated water can increase the yield and productivity of irrigation water.

Response of Sunflower (Helianthus annuus L.) to Nitrogen Levels in Irrigated Areas in Somalia

Aims: SARTEC conducted an experimental study with the objective of determining the effects of various nitrogen rates on sunflower growth and yield in the Afgoi district, Lower Shabelle region.
 Materials and Methods: The study was carried out at the SARTEC experimental farm in Afgoi during the Der season of 2020. The experiment used a Russian kind of sunflower and was laid out in a Randomized Complete Block Design (RCBD) with four replications and four plots for each. The crop was fertilized with different rates of N at 50, 100, and 150 kg ha-1, with a control/unfertilized plot included in each of the replications. Plant height, head diameter, hundred-seed weight, seed, straw, and biological yield, as well as harvest index, were all measured on five plants from each plot for data collection.
 Results: The different fertilizer rates applied to the sunflower crop resulted in highly significant variations in yield and yield components. Seed-related parameters like seed weight and seed yield were influenced substantially more than other variables, including plant height; stem diameter, head diameter, and straw yield. Despite having the highest seed yield, plots with 150 kg of N ha-1 were not more cost-effective than plots with 100 kg ha-1.
 Conclusion: In Somalia, 100 kg of N per hectare is the ideal rate for maximizing sunflower revenue and production while adhering to best management practices.

Response of Imidazolinone-Resistant Sunflower to Various Drift Rates of Glyphosate, Glufosinate and Indaziflam

Imidazolinone (IMI) herbicides are used in sunflower due to the need for sunflower broomrape control, and IMI - resistant sunflower has become common in Turkey. Cereal fields and orchards are often in close vicinity to sunflower fields, and herbicide drift from these areas can adversely affect sunflower. Fields experiments were conducted at Edirne and Ankara, Turkey, in 2018 and 2019 to quantify the sunflower (IMI - resistant) response to various simulated drift rates of glyphosate, glufosinate, and indaziflam. Herbicides were applied to sunflower at 12.5, 6.25, 3.125, and 1% of recommended rates. Crop injury was visually evaluated at 7, 14, and 28 d after treatment (DAT), and plant responses to herbicides were assessed at harvest. Sunflower was injured by all rates of glyphosate applied, with 15 to 100% (in Edirne) and 9 to 84% (Ankara) injury at 28 DAT. Glufosinate - related injury was 5 to 58% in Edirne and 7 to 43% in Ankara at 7 DAT, and decreased with time. In contrast, indaziflam caused no significant crop injury or yield losses. The recommended rates of 6.25% and 12.5 of glyphosate killed all sunflower plants in 2019, while in 2018 the yield loss was 100% only at recommended rate of 12.5% glyphosate. Lower rates of glyphosate reduced yield by 2 to 87% in 2018 and 18 to 62% in 2019. On the other hand, the two highest rates of glufosinate resulted in a yield reduction of 9 and 6% in 2018, respectively, but not in 2019. Injury at early stages after exposure is a good indicator of the impact of glyphosate drift on sunflower yield.

Response of sunflower to salt and alkali stress induced by biogas slurry irrigation

Response of sunflower to salt and alkali stress induced by biogas slurry irrigation

Effect of salinity on oleic sunflower (Helianthus annuus Linn.) under drip irrigation in arid area of Northwest China

To achieve secure and efficient saline water irrigation in arid areas, a field experiment was conducted to evaluate the salt distribution in the soil profile and response of sunflower (Helianthus annuus L.) to salinity from 2018 to 2020. The experiment included five levels of irrigation water salinity (ECi = 0.5 dS/m, 3.3 dS/m, 4.9 dS/m, 6.6 dS/m and 8.2 dS/m). The results indicated that the soil salinity rose slightly and was maintained in balance in the first two years owing to the moderate freshwater irrigation after planting. In 2020, surface salinity accumulation occurred when the ECi was greater than 3.3 dS/m. The average soil salinity at 0–100 cm soil depth was near that of the irrigation water. The effects of irrigation water salinity on plant growth and yield were also investigated. Salinity hindered the growth of the sunflower, which was indicated by a decrease of plant height, biomass, and plant water content. Salinity also reduced sunflower yield by reducing the disk diameter and 100-grain weight. IWP increased in the first two years and then decreased in the third year with an increase in the irrigation water salinity. The salinity threshold for oleic sunflower was 1.3 dS/m, and the sunflower seed yield decreased by 4.9% for every 1 dS/m increase in soil salinity. To ensure a seed yield of over 75%, the soil salinity should be less than 6.4 dS/m. It was concluded that for oleic sunflower drip irrigation in arid areas, the plant, should be irrigated with 80 mm of freshwater to leach salt after planting. This not only ensures that the seed yield is no less than 85% but also maintains a balanced soil salinity after harvest when the ECi increases to 8.2 dS/m.

Sunflower Response to Application of L-Ascorbate Under Thermal Stress Associated with Different Sowing Dates

Sunflower Response to Application of L-Ascorbate Under Thermal Stress Associated with Different Sowing Dates

Comparative hormonal and metabolic profile analysis based on mass spectrometry provides information on the regulation of water-deficit stress response of sunflower (Helianthus annuus L.) inbred lines with different water-deficit stress sensitivity

Water-deficit stress is the most important abiotic stress restricting plant growth, development and yield. The effects of this stress, however, depend on genotypes, among other factors. This study assembles morpho-physiological and metabolic approaches to assess hormonal and metabolic profile changes, upon water-deficit stress, in the shoot and roots of two contrasting sunflower inbred lines, B59 (water-deficit stress sensitive) and B71 (water-deficit stress tolerant). The analyses were carried out using mass spectrometry and performing a multivariate statistical analysis to identify relationships between the analyzed variables. Water-deficit stress reduced all morpho-physiological parameters, except for root length in the tolerant inbred line. The hormonal pathways were active in mediating the seedling performance to imposed water-deficit stress in both lines, although with some differences between lines at the organ level. B59 displayed a diverse metabolite battery, including organic acids, organic compounds as well as sugars, mainly in the shoot, whereas B71 showed primary amino acids, organic acids and organic compounds predominantly in its roots. The discrimination between control and water-deficit stress conditions was possible thanks to potential biomarkers of stress treatment, e.g., proline, maleic acid and malonic acid. This study indicated that the studied organs of sunflower seedlings have different mechanisms of regulation under water-deficit stress. These findings could help to better understand the physio-biochemical pathways underlying stress tolerance in sunflower at early-growth stage.

Modulating response of sunflower (Hellianthus annuus) to induced salinity stress through application of engineered urea functionalized hydroxyapatite nanoparticles.

Agro-nanotechnology aims to improve the quality and quantity of plants and plant products while preserving environmental health. Contemporary anecdotal studies that provide representation of the use of nanostructures as fertilizers, pesticides, and plant growth regulators have highlighted the need to determine the effect of such modified nanofertilizers on transforming plant yield under abiotic stress. Present study was performed to modulate the physiological response of Hellianthus annuus through the application of Urea capped hydroxyapatite nanoparticles (Urea-HANPs) in stressed environment. Hydroxyapatite nanoparticles were synthesized via co-precipitation method, functionalized with urea and characterized through a series of contemporary techniques of transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. We observed that Urea-HANPs significantly (p < .05) ameliorated resistivity in plant to osmotic stress by enhancing agronomic and physiobiochemical attributes. Elevated chlorophyll contents were reported from tested leaves treated with Urea-HANPs in T6 (0.05 M NaCl + 10 μg/ml Urea-HANP) under induced salinity stress. Data revealed significant decrease in osmolytes at T3 (0.1M NaCl), and T4 (0.2M NaCl) which was significantly ameliorated in T9 (0.1M NaCl + 10μg/ml Urea-HANPs) and T12 (0.2M NaCl + 10μg/ml Urea-HANPs). The antioxidant system was boosted up by the application of Urea-HANPs preventing the plant from oxidative stress by scavenging reactive oxygen species (ROS). It has been concluded that alleviation in impact of osmotic stress on plant through the use of Urea-HANPs was coupled with elevation in photosynthetic performance, stimulation of osmolytes and boosting antioxidant system of plants.

Sulfate-Based Fertilizers Regulate Nutrient Uptake, Photosynthetic Gas Exchange, and Enzymatic Antioxidants to Increase Sunflower Growth and Yield Under Drought Stress

The challenging impact of drought to agricultural productivity requires the adoption of mitigation strategies with a better understanding of underlying mechanisms responsible for drought tolerance. The present study aimed at investigating the effects of sulfur-based fertilizers on mitigation of drought stress in sunflower. Sulfate-containing fertilizers, viz., ammonium sulfate, zinc sulfate, magnesium sulfate, potassium sulfate, and gypsum, were initially evaluated at two different rates (10 and 20 mg kg−1 soil equivalent to 20 and 40 kg ha−1, respectively) for nutrient uptake and growth-promoting traits in sunflower seedlings (cv. Hysun-33). The best performing fertilizer (gypsum) was then selected to evaluate the response of sunflower under drought stress imposed at flowering stage for three weeks (25–30% water holding capacity). Results indicated significant amelioration of drought stress with higher activity of photosynthetic apparatus, upregulation of antioxidative enzymes, and increased achene yield by gypsum application. In comparison to control, gypsum-treated plants (20 mg kg−1 soil) exhibited higher water status (32%), leaf photosynthetic rate (29%), transpiration rate (67%), and stomatal conductance (118%) under drought stress. The antioxidant enzyme activities of catalase, guaiacol peroxidase, and superoxide dismutase were also increased by 67%, 62%, and 126%, respectively, resulting in higher achene yield (19%) under water-deficit conditions. This study indicates that the application of sulfur-based fertilizers (gypsum) can be used to induce drought tolerance and obtain high sunflower yields under drought stress, and furthermore, it is a cost-effective strategy resulting in high benefit–cost ratio with respect to no gypsum application.

Genome-Wide Expression and Alternative Splicing in Domesticated Sunflowers (Helianthus annuus L.) under Flooding Stress

Approximately 10% of agricultural land is subject to periodic flooding, which reduces the growth, survivorship, and yield of most crops, reinforcing the need to understand and enhance flooding resistance in our crops. Here, we generated RNA-Seq data from leaf and root tissue of domesticated sunflower to explore differences in gene expression and alternative splicing (AS) between a resistant and susceptible cultivar under both flooding and control conditions and at three time points. Using a combination of mixed model and gene co-expression analyses, we were able to separate general responses of sunflower to flooding stress from those that contribute to the greater tolerance of the resistant line. Both cultivars responded to flooding stress by upregulating expression levels of known submergence responsive genes, such as alcohol dehydrogenases, and slowing metabolism-related activities. Differential AS reinforced expression differences, with reduced AS frequencies typically observed for genes with upregulated expression. Significant differences were found between the genotypes, including earlier and stronger upregulation of the alcohol fermentation pathway and a more rapid return to pre-flooding gene expression levels in the resistant genotype. Our results show how changes in the timing of gene expression following both the induction of flooding and release from flooding stress contribute to increased flooding tolerance.