Nigella Damascena Research Articles

Effective callus induction and plant regeneration in callus and protoplast cultures of Nigella damascena L.

In this study we report the development of effective in vitro systems for a medicinal plant Nigella damascena L. comprising: (1) callus induction, (2) somatic embryogenesis in callus cultures with subsequent plant regeneration, and (3) isolation and regeneration of callus-derived protoplasts. Callus development was achieved on 83–100% of hypocotyl and cotyledon explants, whereby Murashige and Skoog medium (MS) supplemented with 3 mg L−1 6-benzylaminopurine and 0.5 mg L−1α-naphthaleneacetic acid (NAA; BN medium) was more advantageous than MS with kinetin and NAA (KN medium). Histological observations of calli revealed the presence of embryogenic zones from which somatic embryos developed on the hormone-free medium. Plant regeneration was observed on 76–95% of calli. A high capacity to form somatic embryos and regeneration was maintained in long-lasting cultures, i.e. even in 2 year old callus.The obtained callus was also a good source tissue for protoplast isolation. By applying a mixture of cellulase and pectolyase, the acceptable yield of viable protoplasts was achieved, especially from hypocotyl-derived callus maintained on BN medium. Protoplasts embedded in an alginate matrix and cultured in modified Kao and Michayluk media re-constructed their cell wall and re-entered mitotic divisions. About 30% of small cell aggregates formed microcalli, which, after the release from alginate, proliferated continuously on KN and BN media, irrespective of the tissue variant used as the protoplast source. Somatic embryo formation and plant regeneration were successful on hormone-free media. An effective plant regeneration system of N. damascena protoplast cultures has been developed and is being reported for the first time.

Identification of the Key Regulatory Genes Involved in Elaborate Petal Development and Specialized Character Formation in Nigella damascena (Ranunculaceae).

Petals can be simple or elaborate, depending on whether they have lobes, teeth, fringes, or appendages along their margins, or possess spurs, scales, or other types of modifications on their adaxial/abaxial side, or both. Elaborate petals have been recorded in 23 orders of angiosperms and are generally believed to have played key roles in the adaptive evolution of corresponding lineages. The mechanisms underlying the formation of elaborate petals, however, are largely unclear. Here, by performing extensive transcriptomic and functional studies on Nigella damascena (Ranunculaceae), we explore the mechanisms underlying elaborate petal development and specialized character formation. In addition to the identification of genes and programs that are specifically/preferentially expressed in petals, we found genes and programs that are required for elaborate rather than simple petal development. By correlating the changes in gene expression with those in petal development, we identified 30 genes that are responsible for the marginal/ventral elaboration of petals and the initiation of several highly specialized morphological characters (e.g., pseudonectaries, long hairs, and short trichomes). Expression and functional analyses further confirmed that a class I homeodomain-leucine zipper family transcription factor gene, Nigella damascena LATE MERISTEM IDENTITY1 (NidaLMI1), plays important roles in the development of short trichomes and bifurcation of the lower lip. Our results not only provide the first portrait of elaborate petal development but also pave the way to understanding the mechanisms underlying lateral organ diversification in plants.

The morphology, molecular development and ecological function of pseudonectaries on Nigella damascena (Ranunculaceae) petals

Pseudonectaries, or false nectaries, the glistening structures that resemble nectaries or nectar droplets but do not secrete nectar, show considerable diversity and play important roles in plant-animal interactions. The morphological nature, optical features, molecular underpinnings and ecological functions of pseudonectaries, however, remain largely unclear. Here, we show that pseudonectaries of Nigella damascena (Ranunculaceae) are tiny, regional protrusions covered by tightly arranged, non-secretory polygonal epidermal cells with flat, smooth and reflective surface, and are clearly visible even under ultraviolet light and bee vision. We also show that genes associated with cell division, chloroplast development and wax formation are preferably expressed in pseudonectaries. Specifically, NidaYABBY5, an abaxial gene with ectopic expression in pseudonectaries, is indispensable for pseudonectary development: knockdown of it led to complete losses of pseudonectaries. Notably, when flowers without pseudonectaries were arrayed beside those with pseudonectaries, clear differences were observed in the visiting frequency, probing time and visiting behavior of pollinators (i.e., honey bees), suggesting that pseudonectaries serve as both visual attractants and nectar guides.

New floristic records from Central Europe 6 (reports 81-98)

The presented sixth part of the series includes 18 new chorological records of vascular plants, five from Poland and thirteen from Slovakia. In Poland, the first spontaneous occurrence of Clinopodium nepeta subsp. nepeta outside cultivation is reported from Kraków. Also new localities of Euphorbia maculata, Panicum capillare, Plantago coronopus and Symphyotrichum ciliatum from southern Poland were found. In Slovakia, new records of alien Cardamine occulta, Lindernia dubia, Nigella damascena, Pistia stratiotes (with map of known records), Sagittaria latifolia, Senecio inaequidens, Silybum marianum and Vinca major were done as well as autochthonous Cotoneaster melanocarpus, Herniaria hirsuta, Verbascum speciosum and Xeranthemum annuum.

The Action of Chemical Mutagens on the Characteristics of Nigella Damascena L. Plants in M1 Generation

The effect of the chemical mutagens EMS (ethyl methanesulfonate), NMU (nitrosomethylurea), and the new mutagen DG-2 on a number of traits of Nigella damascena L. of the variety “Charivnytsya” in the M1 generation was studied. It was found that treating love-in-a-mist with these chemical mutagens changed such characteristics as plant survival, plant height, number of capsules per plant, number of side shoots and number of seeds from one plant. The dependence of the change in the studied traits on the type of chemical mutagen, its concentration and exposure duration was revealed. Nitrosomethylurea had the greatest influence on plant survival. After treatment with this mutagen at a maximum concentration of 0.05% and with a maximum exposure of 16 hours, the number of surviving plants was 4.3%. The effect of DG-2 mutagen at the concentration of 0.5% and 16 hours’ exposure on the survival of M1 plants was the least different from the control group. In this treatment 60.6% of plants survived, with a control value of 61.7%. The tested mutagens caused the appearance in plants of chlorophyll morphoses with a frequency of up to 0.93%, they were characterized by a change in the color of the leaves and capsule leaflets. Nitrosomethylurea had the greatest influence on the plant height and the number of seeds per plant at the concentrations of 0.01 and 0.05% with 6 and 16 hours’ exposure, respectively. After treatment with NMU at the concentration of 0.05% with exposure of 16 hours all plants were found to be unviable. After treatment with NMU at the concentration of 0.01% with 6 hours’ exposure, the average number of seeds per plant was minimal - 17.5 pieces, and plant height - 25.9 cm. The smallest but statistically significant effect on the studied parameters was noted after treatment with mutagen DG-2. In the case of the mutagen concentration of 0.05% and 16 hours’ exposure the average plant height was 40.7 cm, and the average number of seeds - 112.0 pieces, with control values of 47.0 cm and 237.1 pieces, respectively. The revealed changes in the M1 generation imply mutations of different directions in the next generation of love-in-a-mist.

Изучение адаптогенной активности и токсикологической безопасности экстракта жирного масла семян чернушки дамасской

Изучение адаптогенной активности и токсикологической безопасности экстракта жирного масла семян чернушки дамасской

Attraction of green lacewings (Neuroptera: Chrysopidae) to native plants used as ground cover in woody Mediterranean agroecosystems

Using native seeds to establish semi-natural habitats is a novel strategy to restore biodiversity and ecosystem services such as biological control. As green lacewings (Neuroptera: Chrysopidae) are regarded as major biological control agents in different crops, the objective of this study was to test the attractiveness of selected native plant species to lacewings. During a two-year (2016–2017) field experiment near Villarrubia (Andalusia, Spain), 42 native plant species belonging to 13 families were planted. Plant development was monitored, and arthropods were vacuumed from each plot twice during the peak May flowering period. Green lacewings were observed to use 28 of the 36 well developed species to reproduce, feed and/or rest. Chrysoperla lucasina was the predominant species among the captured adults. No clear pattern of attraction common to all species was observed during the two-year sampling period. In 2017, eight plant species showed above-average chrysopid abundance. In addition, Acari abundance correlated positively with chrysopid abundance. Given the attraction of chrysopids, the effect of pests and disease on olive orchards and satisfactory plant development, we consider Biscutella auriculata, Borago officinalis, Silene colorata, Crepis capillaris, Nigella damascena and Papaver rhoeas to be the native plant species best suited to host chrysopids and to restore ground cover in perennial Mediterranean crops.

EFFECT OF FATTY OIL EXTRACT FROM SEEDS OF NIGELLA DAMASCENA L. ON LIPID SPECTRUM IN RATS WITH SIMULATED DYSLIPIDEMIA

The aimof the study is to determine a lipid spectrum of blood plasma and liver in rats in with simulated dyslipidemia against the background of the administration of the fatty oil extract from the seeds of Nigella damascena L.Materials and methods.Laboratory animals – Wistar male rats – were used in the work. To study the hypolipidemic activity, such models as acute Tween, subchronic vitamin-D2 models and a model of chronic heart failure were used. The identifiable parameters were the concentration of cholesterol and triglycerides in the blood serum and liver, as well as the concentration of atherogenic and non-atherogenic lipoproteins in the blood serum, and the atherogenic coefficient.Results.As a result of the study, it was found out that a course administration of the fatty oil extract from the seeds of Nigella damascena L. against the background of simulated chronic heart failure (CHF) by the right ventricular type, normalizes the lipid spectrum of the experimental animals’ blood serum, causing an increase in the concentration of high-density (non-atherogenic) lipoproteins, and reduces the concentration of low-density (atherogenic) lipoproteins. A single administration of the fatty oil extract from the seeds of Nigella damascena L. promotes the correction of lipid metabolism disorders under the conditions of acute Tween lipidopathy, while the direction of the object being studied reduces the concentration of cholesterol and triglycerides in the liver and blood serum under the conditions of subchronic dyslipidemia. At the same time, the effect of the use of the fatty oil extract from the seeds of Nigella damascena L. was not inferior to “Omaсor”, the reference drug.Conclusion.The possibility of using a fatty oil extract from the seeds of Nigella damascena L. for preventive and therapeutic aims in cardiovascular diseases has been established.

Nigella damascena L. essential oil and its main constituents, damascenine and β-elemene modulate inflammatory response of human neutrophils ex vivo

Nigella damascena L belongs to Ranunculaceae family and is mentioned in Eastern traditional medicine for the treatment of high temperatures, regulation of menstruation or catarrhal affections. The anti-inflammatory activity of compounds present in the essential oil obtained from seeds of this plant can be found in literature, however no studies on immunomodulatory activity are provided. Hence, in this work anti-inflammatory activity of N. damascena seed essential oil as well as damascenine and main compound β-elemene was evaluated on ex-vivo lipopolysaccharide (LPS)–stimulated human neutrophils. For isolation of damascenine fast and efficient protocol was elaborated using high performance countercurrent chromatography technique for the first time. Also detailed spectroscopic characteristic of damascenine was provided for the first time. Damascenine was separated from the essential oil in a mixture of petroleum ether/acetonitrile/acetone (2:1.5:0.5 v/v/v) in reversed phase mode in 12 min with 99.47% purity. Essential oil, damascenine and β-elemene presented immunomodulatory activity evaluated in LPS–stimulated neutrophils ex vivo. All studied samples significantly inhibited release of interleukin 1 beta (IL-1β) and interleukin 8 (IL-8). What is more, damascenine and β-elemene decreased matrix metallopeptidase 9 (MMP-9) production similar to dexamethasone. The release of tumor necrosis factor (TNF-α) was also inhibited in all range of concentrations, however the activity was weaker then activity of dexametasone. The previously reported anti-inflammatory activity of damascenine and β-elemene investigated in murine models was confirmed in our study on human neuthrophils suggesting their possible strong inhibitory effect on inflammatory response progression.

Nigella damascena L. Essential Oil-A Valuable Source of β-Elemene for Antimicrobial Testing.

The most commonly used plant source of β-elemene is Curcuma wenyujin Y. H. Chen & C. Ling (syn. of Curcuma aromatic Salisb.) with its content in supercritical CO2 extract up to 27.83%. However, the other rich source of this compound is Nigella damascena L. essential oil, in which β-elemene accounts for 47%. In this work, the effective protocol for preparative isolation of β-elemene from a new source—N. damascena essential oil—using high performance counter-current chromatography HPCCC was elaborated. Furthermore, since sesquiterpens are known as potent antimicrobials, the need for finding new agents designed to combat multi-drug resistant strains was addressed and the purified target compound and the essential oil were tested for its activity against a panel of Gram-positive and Gram-negative bacteria, fungi, and mycobacterial strains. The application of the mixture of petroleum ether, acetonitrile, and acetone in the ratio 2:1.5:0.5 (v/v) in the reversed phase mode yielded β-elemene with high purity in 70 min. The results obtained for antimicrobial assay clearly indicated that N. damascena essential oil and isolated β-elemene exert action against Mycobacterium tuberculosis strain H37Ra.

Distribution area of the two floral morphs of Nigella damascena L. (Ranunculaceae): a diachronic study using herbarium specimens collected in France

Perianth dimorphism in Nigella damascena (Ranunculaceae) has been documented for four centuries, and its genetic basis started to be studied almost a century ago. Based on herbarium collections, we reconstructed the evolution of the distribution area of the wild-type (perianth composed of a calyx and nectariferous petals) and mutant (apetalous) floral morphs in mainland France over the last two centuries. We showed that the collection localities of the wild-type morph are mostly concentrated in the southern coastal areas of France, whereas the collection localities of the mutant morph were less numerous but more scattered in France. The collection effort of both morphs peaked in the second half of the nineteenth century and continuously decreased afterwards. Results are interpreted taking into account the biases in the constitution of a herbarium collection. Knowledge about the spatial distribution and the frequency of occurrence of wild-type and mutant populations through time will help botanists and evolutionary biologists investigate the origin and ecological grounds for the maintenance and propagation of the apetalous morph in the wild.

Analysis of Chromosome Condensation/Decondensation During Mitosis by EdU Incorporation in Nigella damascena L. Seedling Roots.

To investigate the chromosome dynamics during mitosis, it is convenient to mark the discrete chromosome foci and then analyze their spatial rearrangements during prophase condensation and telophase decondensation. To label the chromosome regions in plant chromosomes, we incorporated the synthetic nucleotide, 5-ethynyl-2'-deoxyuridine (EdU), which can be detected by click-chemistry, into chromatin during replication. Here, we described a protocol of a method based on the application of semi-thin sections of Nigella damascena L. roots embedded in LR White acrylic resin. The thickness of semi-thin (100-250 nm) sections is significantly lower than that of optical sections even if a confocal microscope was used. This approach may also be suitable for work with any tissue fragments or large cells (oocytes, cells with polytene chromosomes, etc.).

Thermal Characterization of Extracts Obtained from Different Parts of Nigella damascena (Ranunculaceae) by TG and DSC

The increased search for herbal products has generated an increasing interest in improving the quality control of extracts by pharmaceutical industry since these are raw materials of great importance by their quality and versatility. Thermal analysis such as thermogravimetry (TG) is a technique of high sensitivity, reproductibility and rapid response to variations in mass, obtaining results related to the composition and thermal stability of the sample, being important to the characterization of raw plants. Thermogravimetric techniques and differential scaning calorimetry (DSC) used for the study of pre-formulation of drug-excipient compatibility have been gaining importance. These techniques are being used for the verification of possible interactions between drugs and excipients. Aiming at studying the behavior of a plant extract, using these thermoanalytical techniques, the plant species Nigella damascena semen and Nigella damascena herba was used. This plant has healing and anti-inflammatory properties. The methodology for obtaining the extract followed the European Pharmacopoeia methodology. The TG and DSC curves were obtained under nitrogen and air atmosphere (20 mL/min) at a heating rate of 10�C/min. The TG and DSC tests were analyzed within a temperature range from 25 to 1000�C.

Bioprospecting for seed oils from wild plants in the Mediterranean Basin for biodiesel production

In the Mediterranean Basin, petroleum energy resources are scarce. For an environmentally sustainable solution, the seeds collected from wild plants indigenous to this area could be used as biodiesel producers to meet the energy demand. For this, the fatty acid profiles of seed oils from 127 species belonging to 30 plant families, all native of the Mediterranean Basin, were surveyed in a search for fossil-fuel substitutes. The saponification number (SN, mg KOH/g), iodine value (IV, g I2/100 g), cetane number (Ф), higher heating value (δ, MJ/kg), cold filter-plugging point (CFPP, °C), density (ρ, g/cm3), induction period (IP, h) and kinematic viscosity (η, mm2/s) were empirically determined and then used to establish the suitability of the different seed oils for biodiesel production. The aptness to serve as biodiesel was determined by applying the specification for biodiesel standard made by several organizations. In addition to three already well-characterized species, the fatty acid methyl esters from the seeds of Conium maculatum (Ф = 53.7; δ = 40.1), Eryngium maritimum (Ф = 53.2; δ = 40.2), Nigella damascena (Ф = 58.1; δ = 40.1), Portulaca oleracea (Ф = 62.9; δ = 40.5), Prangos uechtritzii (Ф = 52.8; δ = 40.1), and Tribulus terrestris (Ф = 59.4; δ = 40.1), meet the major quality standards set by several organizations, and thus are suitable for biodiesel production. Data from empirical models used for estimating biodiesel properties was compared with experimental data from biodiesel prepared with available seeds, and good correlations between the two methodologies were found.The sowing of selected species in natural habitats, in addition to providing a valuable resource, i.e. biodiesel, both the Mediterranean Basin ecoregions and unproductive agricultural lands could be improved as appropriate habitats for wildlife, and in parallel this action would create employment in rural areas using natural resources.

Нові знахідки у флорі міст Північного Приазов’я

<p>Northern Azov is unique region in origin and conditions, which modern flora developed in conditions of active human economic activities. Anthropogenic transformations have resulted to changes in vegetation cover and wild plant communities are transformed into synanthropic floral complexes.</p><p>The results achieved through our expeditionary studies conducted in 2013-2016 in the Northern Azov (in the administrative boundaries of the cities Berdyansk, Primorsk (Zaporizhia region), and Genichesk (Kherson region). In total, we founded new locations for 25 vascular plants: <em>Armoracia rusticana</em> P.G. Gaertn., B. Mey. & Scherb., <em>Apium graveolens</em><strong> </strong>L., <em>Arabis</em><em> </em><em>recta</em><em> </em>Vill., <em>Aster amellus</em><strong> </strong>L., <em>Acalypha australis L.</em>, <em>Mahonia aquifolium</em> (Pursh) Nutt., <em>Oxybaphus</em><em> </em><em>nyctagineus</em> (Michx.) Sweet, <em>Bidens</em><em> </em><em>frondosa</em>. L., <em>Ipomoea purpurea</em><strong> (</strong>L.), <em>Sedum acre</em> L., <em>Clematis vitalba</em> L., <em>Scilla</em><em> </em><em>siberica</em> Haw., <em>Zea majus</em> L., <em>Philadelphus</em><em> </em><em>coronarius</em> L., <em>Robinia</em><em> </em><em>viscosa</em> Vent., <em>Fagopyrum esculentum</em> Moench, <em>Nigella damascena</em> L., <em>Convallaria</em><em> </em><em>majalis</em> L., <em>Rubus anatolicus</em> (Focke) Focke ex Hausskn., <em>Ricinus</em><em> </em><em>communis</em> L., <em>Lablab</em><em> </em><em>purpureus</em> L., <em>Chrysanthemum segetum</em> L., <em>Gaillardia pulchella</em> Foug., <em>Antirrhinum majus</em> L., Tagetes patula L. In addition, we provided a brief description of their habitats and described new locations for new and previously marked aboriginal, alien, and cultivated plants that are capable of savagery for Northern Azov flora. Among all annotated species the significant proportion are the alien species that fall out of cultivation.</p>

Antioxidant and antihypertensive properties of phenolic–protein complexes in extracted protein fractions from Nigella damascena and Nigella arvensis

The study involved the investigation of the antioxidant and antihypertensive properties of the phenolic–protein complexes obtained from isolated protein fractions from Nigella damascena and Nigella arvensis. Protein fractions from flours made from the seeds of Nigella species were isolated and included albumin, globulin, glutelin-1, glutelin-2 and prolamin. Albumin and glutelin-1 fractions were the predominant proteins in the two Nigella species studied in terms of protein content and percent protein yield. Free phenolics were extracted from the isolated protein fractions by methanol treatment at either 25 °C or 60 °C followed by acid and base hydrolysis to obtain bound phenolics. The free and bound phenolic composition was assessed by RP-HPLC. The highest phenolic content was observed in the free phenolic extract at 25 °C (FP-25 °C) in glutelin-2 of both Nigella species. The free and bound phenolics of the protein fractions were tested for angiotensin converting enzyme (ACE) inhibitory and antioxidant activities. The greatest ACE inhibitory activities were seen for the free and bound phenolic extracts obtained from glutelin-2 and globulin fractions of both Nigella species. The highest antioxidant activities were observed in the extracted phenolics from glutelin-1 and globulin from N. damascena and albumin from N. arvensis. Only a weak correlation was seen between the phenolic content of the isolated protein fractions and the ACE inhibitory and antioxidant activities. The present study indicates that phenolic–protein complexes in the Nigella species have significant antioxidant and ACE inhibitory properties although the bioactivities of the protein fractions are not closely related to their total phenolic content.

Flexibility in the structure of spiral flowers and its underlying mechanisms.

Spiral flowers usually bear a variable number of organs, suggestive of the flexibility in structure. The mechanisms underlying the flexibility, however, remain unclear. Here we show that in Nigella damascena, a species with spiral flowers, different types of floral organs show different ranges of variation in number. We also show that the total number of organs per flower is largely dependent on the initial size of the floral meristem, whereas the respective numbers of different types of floral organs are determined by the functional domains of corresponding genetic programmes. By conducting extensive expression and functional studies, we further elucidate the genetic programmes that specify the identities of different types of floral organs. Notably, the AGL6-lineage member NdAGL6, rather than the AP1-lineage members NdFL1/2, is an A-function gene, whereas petaloidy of sepals is not controlled by AP3- or PI-lineage members. Moreover, owing to the formation of a regulatory network, some floral organ identity genes also regulate the boundaries between different types of floral organs. On the basis of these results, we propose that the floral organ identity determination programme is highly dynamic and shows considerable flexibility. Transitions from spiral to whorled flowers, therefore, may be explained by evolution of the mechanisms that reduce the flexibility.

Flower development schedule andAGAMOUS-like gene expression patterns in two morphs ofNigella damascena(Ranunculaceae) differing in floral architecture

Love-in-a-mist (Nigella damascena) is an annual species of Ranunculaceae native to the Mediterranean Basin, characterized by delicate flowers lying on long lacy bracts. Two floral morphs of N. damascena, designated [P] and [T], differ in the identity and number of perianth organs and in the position of the perianth–androecium boundary on the meristem. They both occur in the wild. Here we describe a precise comparative schedule of floral development in the two morphs. We divided the sequence of developmental events affecting the floral meristem into six stages and related them to the height of the elongating stem and to the time elapsed after the beginning of stem elongation. In addition, we characterized the expression pattern of C-class genes in floral organs of both morphs in an attempt to better characterize the differences between the two floral groundplans. In the [T] morph an expansion of the expression domain of AGAMOUS (AG) paralogues outside the fertile organs was observed, correlating with the change in identity of the inner perianth organs. Expression of AG-like genes in the sepal-like organs suggests these are not identical to true sepals at the molecular level. The morpho-temporal framework we have defined will allow us to compare various gene expression profiles at targeted developmental stages in both morphs, providing further insight into the molecular control of the floral dimorphism in N. damascena and into the processes underlying the transition from a differentiated (bipartite) to an undifferentiated (unipartite) perianth.

Floral vascular patterns of the double-flowered and wild-type morphs of Nigella damascena L. (Ranunculaceae)

The perianth of the double-flowered morph of Nigella damascena L. consists of spirally inserted petaloid sepals and sepal-like organs, similar in shape and colour to the petaloid sepals of the wild-type flower. It is devoid of petals. We compare the vascularization of each organ category of the double flower with that of the wild-type. We show that the vascular patterns of the sepal-like organs and of the petals are identical, and found an inverse relationship between the number of bracts and the number of sepals in the double-flowered morph. These two surprising findings will influence the future evo-devo studies on this plant model.

Variable Phytotoxic Effects of Thymus vulgaris (Lamiaceae) Terpenes on Associated Species

Thymus vulgaris has a chemical polymorphism in which individual plants have an essential oil dominated by either nonphenolic (geraniol, -terpineol, cis-sabinene hydrate, linalool, or 1,8-cineole) or phenolic (carvacrol and thymol) monoterpenes. Using the geraniol, cis-sabinene hydrate, and the two phenolic chemotypes, we tested three hypotheses: (1) chemotypes vary in their influences on germination and growth of associated plant species, (2) associated species respond differentially to individual chemotypes, and (3) soils under thyme canopies will influence associated species differently than do sterile soils. The study was done in Montpellier, France, in settings mimicking natural conditions. In one experiment, survival of both monocots and dicots from the seed bank was lower in soils collected from under thyme plants of the phenolic chemotypes. In a second experiment, we sowed seeds of Daucus carota, Nigella damascena, and Bromus madritensis into soil collected from under thyme plants and covered with canopies of fresh thyme of each chemotype or into control soils. The species showed differential responses in germination and/or growth to the four chemotypes. In a third experiment, germination and growth of D. carota, N. damascena, Bromus erectus, and Picris hieracoides on sterile soil covered with fresh thyme foliage and controls showed differential responses to the four chemotypes; however, these responses were less marked than those on soils collected under thyme plants. These results—coupled with previous demonstrations of chemotype-influenced differential herbivory and parasitism—illustrate the complex influences of genetic variability on multispecies interactions and the individuality of species responses to toxic chemicals.