A simple spray of vitamin C may help rose growers harvest more flowers and produce a richer, chemically more complex essential oil, according to a field experiment conducted in Iran. Researchers found that applying ascorbic acid to rose plants increased flower number, fresh and dry petal yield, and essential-oil content, with the strongest effects recorded at the highest tested concentration, 200 milligrams per liter. Under that treatment, fresh petal production rose by 25.08 percent and dry petal production by 27.72 percent compared with untreated plants. The treatment also altered the oil’s chemical profile, introducing compounds reported to have antimicrobial properties. The findings suggest that an inexpensive antioxidant could influence not only how much plant material roses produce, but also the biochemical composition of a commercially valuable product used in fragrances, cosmetics, food flavoring and traditional remedies. The study, published in BMC Plant Biology, examined roses grown under orchard conditions during the 2022–2023 growing season in Hamoon County, in Iran’s Sistan region.
Ascorbic acid, commonly known as vitamin C, is best known for its role in human nutrition, where it helps maintain connective tissue and functions as a water-soluble antioxidant. Plants also produce and use ascorbate as part of a sophisticated system for controlling reactive oxygen species, chemically reactive molecules generated during normal metabolism and intensified by drought, heat, intense light, disease or other stresses. At moderate levels, reactive oxygen species can act as signals that regulate growth and defense. At excessive levels, however, they can damage proteins, membranes and genetic material. By supplying additional ascorbic acid, growers may help plants maintain redox balance while stimulating physiological pathways associated with flowering and secondary metabolism. Secondary metabolites are compounds not required for basic growth in the same way as sugars or proteins, but they often protect plants, attract pollinators or deter herbivores. In roses, many of these compounds contribute directly to scent, color, antioxidant activity and essential-oil quality.
To test the effect, Hossein Shahraki and colleagues designed a randomized complete block experiment with four replications. This arrangement is widely used in agricultural research because it helps separate treatment effects from variation caused by differences in soil, drainage, sunlight or other local conditions. Rose plants received foliar applications containing 0, 50, 100 or 200 milligrams of ascorbic acid per liter. The zero-concentration group served as the control, allowing the researchers to compare untreated plants with those exposed to progressively larger doses. They measured the number of flowers produced per plant, fresh and dry petal yield per hectare, the percentage of essential oil, total phenolic compounds, total flavonoid compounds and antioxidant activity. They also analyzed the oil using gas chromatography–mass spectrometry, or GC–MS. This technique separates volatile molecules as they pass through a chromatography column and then identifies them according to their mass spectra, producing a chemical fingerprint of the oil.
The clearest production response occurred at 200 milligrams per liter. Although the study reported that all tested ascorbic-acid concentrations improved the measured yield traits, the increases generally became larger as the concentration rose. Fresh and dry petal yields showed the most clearly quantified gains, climbing by roughly one-quarter and more than one-quarter, respectively, relative to the control. More flowers per plant and a higher essential-oil percentage were also observed after treatment. For commercial growers, the distinction between fresh and dry yield matters: fresh petals include the water contained in plant tissues, whereas dry yield reflects the mass remaining after moisture removal and is more closely related to the amount of solid floral material available for processing. Essential-oil percentage, meanwhile, indicates how efficiently that biomass yields volatile compounds during extraction. A treatment that increases both biomass and oil concentration could therefore offer a larger return from the same cultivated area, although production costs and performance across different climates would still need to be evaluated.
The biochemical measurements point to a second effect beyond simple growth promotion. Total phenolic content, total flavonoid content and DPPH antioxidant activity all increased as ascorbic-acid concentration rose. Phenols and flavonoids are broad families of plant compounds that can neutralize free radicals or bind reactive molecules, although their biological activity depends on their precise structures and concentrations. The DPPH assay is a laboratory test in which antioxidants reduce a stable purple radical, causing a measurable change in color. It provides an estimate of radical-scavenging capacity, but it does not by itself demonstrate that a plant extract will produce a particular health effect in humans. In the roses, the stronger DPPH response indicates that ascorbic acid was associated with an increase in extractable antioxidant compounds or activity. The result is consistent with the idea that redox signaling can redirect plant metabolism toward protective chemistry, but it does not establish exactly which molecular pathways were activated.
The GC–MS analysis showed that ascorbic acid changed the balance of volatile constituents rather than merely increasing the total amount of an unchanged oil. In untreated flowers, the principal compounds included d-limonene, phenylethyl alcohol, decane, 9,17-octadecadienal, 1,2-benzenedicarboxylic acid, 9,12-octadecadienoic acid and dodecane. These molecules span several chemical classes, including terpenes, alcohols, aldehydes, hydrocarbons and fatty-acid-related compounds. D-limonene is a terpene associated with citrus-like aromas, while phenylethyl alcohol contributes a characteristic rose-like floral note and is widely used in perfumery. The relative abundance of such molecules helps determine an oil’s fragrance profile, stability and potential commercial value. Because aroma depends on mixtures and concentration ratios, even a modest shift in one constituent can change the sensory character of the final product. The researchers found that ascorbic acid could increase or decrease individual compounds depending on the treatment concentration, revealing a dose-sensitive effect on the plant’s volatile-metabolite network.
At 200 milligrams per liter, the treated roses also produced compounds that were not detected in the control plants, including beta-isobicyclogermacrene and phthalic acid. The study identified novel compounds associated with the highest treatment as having antimicrobial properties. That observation is potentially important for rose-oil applications, since antimicrobial activity can influence preservation, cosmetic formulations and the development of plant-derived products. Yet chemical detection is not equivalent to proven practical performance. GC–MS can indicate that a compound is present and estimate its relative abundance, but dedicated microbiological experiments are required to determine whether the complete oil inhibits specific bacteria or fungi, at what concentrations and under which conditions. The biological activity of an essential oil also depends on interactions among its constituents, extraction method, storage, formulation and target organism. The reported chemical changes therefore provide a promising lead rather than a finished antimicrobial product or a substitute for standardized testing.
The researchers’ results fit a broader agricultural effort to use plant biostimulants—substances that improve crop performance without acting primarily as conventional fertilizers or pesticides—to increase productivity under environmental stress. Ascorbic acid is attractive in this context because it is familiar, relatively accessible and already part of plant antioxidant chemistry. Still, the experiment was conducted at one rose orchard, during one growing period, with four tested concentrations and four experimental replications. Those conditions provide evidence of an association between treatment and plant responses, but they do not guarantee that the same dose will produce the same result in other rose varieties, soils or climates. Field-scale trials would need to examine application timing, spray frequency, weather, irrigation, labor, residue and the economics of essential-oil extraction. Researchers would also need to confirm the findings in the final version of the article and compare the sensory properties, storage stability and antimicrobial performance of oils produced under different treatments.
For now, the study presents vitamin C as a potentially practical tool for intensifying both rose production and floral chemistry. Its most striking message is that a foliar antioxidant treatment may influence the entire chain from plant physiology to commercial quality: more flowers provide more petals, more petals can yield more oil, and the treatment can reshape the volatile compounds that define the oil’s identity. The findings also illustrate why agricultural interventions cannot be judged solely by crop weight. A larger harvest is valuable, but changes in phenols, flavonoids, antioxidant activity and aroma molecules may determine whether the resulting material commands a higher price or serves a different market. The University of Zabol funded the work through grant IR-UOZ-GR 2874, and the authors declared no competing interests. Further testing will determine whether the promising 200-milligram-per-liter treatment can move from a controlled field experiment into reliable commercial rose cultivation.
Subject of Research: The effects of foliar ascorbic acid on rose flower yield and essential-oil composition
Subject of Research: Agriculture
Article Title: The effect of ascorbic acid on flower yield, quantity and quality of rose essential oil
Article References: Shahraki, H., Emamjomeh, A., Allahdou, M., & Beizaei, H. (2026). The effect of ascorbic acid on flower yield, quantity and quality of rose essential oil. BMC Plant Biology. https://doi.org/10.1186/s12870-026-09823-w
Image Credits: AI Generated
DOI: 10.1186/s12870-026-09823-w
Keywords: ascorbic acid, rose cultivation, essential oil, flower yield, antioxidants, secondary metabolites, GC–MS, phenolic compounds, flavonoids, antimicrobial compounds
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SCIENMAG. (August 28, 2026). Ascorbic Acid Effects on Rose Flower Yield, Essential Oil Quantity and Quality. https://scienmag.com/ascorbic-acid-effects-on-rose-flower-yield-essential-oil-quantity-and-quality/
SCIENMAG. “Ascorbic Acid Effects on Rose Flower Yield, Essential Oil Quantity and Quality.” Scienmag, 28 August 2026, https://scienmag.com/ascorbic-acid-effects-on-rose-flower-yield-essential-oil-quantity-and-quality/. Accessed 28 August 2026.
SCIENMAG. “Ascorbic Acid Effects on Rose Flower Yield, Essential Oil Quantity and Quality.” Scienmag. August 28, 2026. https://scienmag.com/ascorbic-acid-effects-on-rose-flower-yield-essential-oil-quantity-and-quality/
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