Effect of plant density and application rates of vermicompost on essential oil content and composition of Balm (Melissa officinalis L.)

Field and laboratory experiments were conducted at two sites in Nova Scotia during 2001 and 2002 to assess the potential to grow fennel (Foeniculum vulgare Mill.) as an essential oil crop in the Maritime region of Canada. Three cultivars—`Shumen', `Berfena', and `Sweet Fennel'—and two seeding dates—24 May and 8 June—were evaluated. Essential oil yields and composition were determined and compared to commercially available fennel essential oil from the U.S. The highest herbage yields were produced by `Shumen' from the earlier seeding date. Essential oil content and yields were lowest in `Sweet Fennel' and highest in `Shumen'. The major component of the essential oil was anethole, 47% to 80.2%. Other major components of the essential oil were methyl chavicol, fenchone, α-phellandrene, α-pinene, ortho cymene, β-phellandrene, fenchyl acetate, β-pinene, and apiole. The essential oil composition was unique to each cultivar. The highest methyl chavicol content was in `Shumen', while the highest concentration of phellandrene, fenchyl acetate and apiole were detected in `Sweet Fennel' oil. Fenchone, ortho cymene, β-pinene, α-phellandrene, and α-pinene were the highest in `Berfena'. The composition of the oil was similar to the commercially purchased oil and met industry requirements of oil composition. The results suggest there is potential to grow fennel as an essential oil crop in Nova Scotia.

Blessed thistle (Cnicus benedictus L.) is an abundant resource with huge phytochemical and agronomic potentials. Their variation in response to agronomic techniques needs to be explored. Field studies were laid out to assess plant density and nitrogen fertilizer (N) effects on blessed thistle plant height, branches number (m-2), vegetative variables and RGR (relative growth rate), CGR (crop growth rate), LAR (leaf area ratio), NAR (net assimilation rate), as growth variables along with blessed thistle essential oil content, yield and compositions in two growing seasons. A three replicated factorial combination of plant densities (5, 10, 15, 20 and 25 plants m-2) and N levels (0, 50, 100 and 150 kg ha-1) in a randomized complete-block design were conducted. Addition of 100 kg N ha-1with 15-20 plants m-2caused a significant increase in vegetative and growth variables. Although the essential oil content declined by 28 and 39 % as N rate level rose from 0 to 150 kg ha-1, essential oil yield peaked at 40-80 kg N ha-1 in both years. The GC and GC/MS analysis showed that eicosane was the dominant component of the essential oil (31-65 %), followed by isopropyl hexadecanoate (5.7-9.2 %), octadecane (3.5-10.5 %) and cryptomerione (3.1-7.1 %) which presented variations across the treatments. Application of N resulted in a decrease in the eicosane and an increase in the proportion of isopropyl hexadecanoate, octadecane and cryptomerione. It can be concluded that optimizing agronomic management techniques could be an effective approach to improve growth, essential oil content and composition of the plant.

Plant density and manure application affected yield and essential oil composition of Bakhtiari savory (Satureja bachtiarica Bunge.)

Foliar application of Ca(NO3)2 and KNO3 affects growth, essential oil content, and oil composition of French tarragon

Foliar boron fertilization as factor affecting the essential oil content and yield of oil components from flower heads of Arnica montana L. and Arnica chamissonis Less. cultivated for industry

The reactions of Majorana hortensis, Melissa officinalis, Mentha piperita and Thymus vulgaris were investigated in controlled conditions to compare their responses on drought stress concerning yield, essential oil (EO) content and composition. Biomass and essential oil concentration were significantly decreased in each species similarly, if they were grown at 40% level of soil water capacity (SWC) compared to the ones growing at 70% SWC. The largest changes were detected in lemon balm (4.47-fold difference in biomass, 2.78-fold difference in EO content) while the response of marjoram was the modest one (1.95-fold in biomass, 1.21-fold in EO content). We found species specific quantitative modifications in the EO composition. The ratio of terpinene-type components increased in the EO of both thyme and marjoram to the expense of their characteristic compounds thymol, carvacrol and sabinyl compounds, respectively. The composition of lemon balm and peppermint, however, did not show considerable changes.

Essential oil yield and composition of Ocimum basilicum L. at different phenological stages, plant density and post-harvest drying methods

Phoenix dactylifera L., is a monocotyledonous tree belonging to the family Arecaceae or Palmaceae. In Iranian traditional medicines, the distilled water from the date palm spathe is used as tonic, sedative and calmative herbal medicine. In this study, for the first time, the essential oil content and composition of spathe from seven date palm varieties, Phoenix dactylifera L. (var. Mozafati) (male and female trees), Zahedi, Hallilehie, Piarom, and Keroot, Mordasangh, Medjool) growing in Bam, South of Iran, were determined by means of gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) analyses. The results showed a significant difference between the weight of spathe per tree, essential oil percentage and essential oil yield of different varieties at P<0.01. Comparison of mean values showed the highest essential oil percentage (0.21 %, 0.20 % and 0.15 %) were obtained from Piarom, Zahedi and Mozafati varieties, respectively. Seventeen compounds were identified in the essential oils with 3,4-dimethoxy toluene (55.2-70.7 %), p-methyl anisol (4.5-28.5 %) and 2,6-dimethoxy toluene (9.0-19.9 %) as main components. These compounds have anti-paroxysm effects or may prevent the advance stage of Alzheimer. Cluster analysis showed that the Medjool variety was separated from other varieties. Imported varieties from other regions of Iran (Zahedi, Piarom, Hallilehie and Mordasangh) were set into one group and the inherent varieties (Keroot, Mozafati) were set into another group. The results showed that the varieties from one geographical region had a close or relatively the same essential oil compositions.

A field experiment was conducted on three cultivars (Italian Giant, Italian Plain, and Local) of parsley to compare plant growth, herb fresh weight, and essential oil (EO) content, yield and composition at three harvest times (Day 1, 47, and 91) in response to phosphorus (P) application rates (0, 12, 24, and 36 kg ha−1). Repeated measures analysis revealed that the ideal P rate for the growth of parsley and its EO yield is 24 kg ha−1; whereas the second harvest gives the highest height and weight; and the third harvest gives the highest EO content and yield. At all harvests, the highest EO content was obtained from Italian Giant fertilized with 36 kg ha−1 P. β-myrcene, 1,3,8-p-menthatriene, β-phellandrene, and myristcin were the major compounds in all three cultivars, but their ideal P fertilization and harvest time varied with cultivar. This study showed biomass, EO content and yield, and the accumulation of EO constituents of parsley cultivars are influenced by P application and harvest date in different ways.

St. John's wort is an important medicinal plant that contained a wide range of secondary metabolites such as naphthodianthrones, phloroglucinols and essential oil. The quality of Hypericum perforatum was determined by several cultural practices. In this research essential oil content and composition determined at before flowering, full flowering and fruit set stages. Water distillation was used for essential oil extraction. Essential oil composition was determined by GC and GC/MS. On the basis of the results herb of Saint John's wort in full flowering stage has higher amount of essential oil (0.35 ml/100 g dry weight) than before flowering and fruit set stage (0.12 and 0.16 ml/100 g dry weight, respectively). The essential oil contains longifolene, α- and γ-eudesmol, spathulenol, bicyclogermacrene, β-caryophyllene, α-cadinol, α-cadinene and β-bisabolene as major constituents. These constituents are affected by harvest time. In this respect longifolene is identified in oil sample before flowering and at fruit set stage (18.71 and 21.99%, respectively) but unidentified in the oil of full flowering stage. The amount of bicyclogermacrene was the highest (16.93%) at full flowering stage and decreased sharply at other harvest time. According to the results the most suitable time for harvesting of Hypericum perforatum with respect to essential oil content and composition is full flowering.

Altitude is an important ecological factor that significantly affects essential oil content, yield and composition. In this study, conducted to examine the effects of altitude on essential oil content and composition of O. majorana, plant samples were collected from the southern region of Türkiye at the beginning of flowering period from seven different altitudes (766 m, 890 m, 968 m, 1079 m, 1180 m, 1261 m and 1387 m) at 100 m intervals. The highest percentage of essential oil (6.50%) obtained by hydro-distillation was determined at 766 m altitudes. The GC–MS analyses revealed that low altitude affected some essential oil components positively. The linalool ratio, which is the major component of the essential oil of O. majorana species, was the highest at 766 m (79.84%) altitudes. Borneol, linalool oxide, trans-linalool oxide, caryophyllene, a-humulene, germacrene-D and bicyclogermacrene components yielded high values at 890 m altitudes. Thymol and α-terpineol, which have an important place in the essential oil composition, increased at 1180 m altitudes; a-terpinene, cis-sabinene hydrate, terpinene-4-ol and carvacrol increased at 1387 m altitudes.

In a split-plot arrangement of randomized complete block design with 3 replication the effect of nitrogen fertilizer at 3 levels of 0(No), 75(N1) and 150 (N2) Kg/ha and plant density of 35×10cm (28.6 plant/m2=D1) and 35×20cm (14.3 plant/m2=D2) was studied on the essential oil content and composition of Tanacetum parthenium CV. Zardband. The essential oil was obtained by hydro distillation from the herb of the plant. The oil content significantly affected by nitrogen and plant density. According to the results nitrogen fertilizer and plant density had important role on the essential oil content and composition of Tanacetum parthenium CV. Zardband. N2D2 (150 Kg/ha N and 14.3 Plant/m2) treatment produced the highest amount of oil content. In N1D1 (75 kg/ha N and 28.6 plant/m2) treatment the largest amount of camphore and chrysanthenyl acetate was produced.

Salicylic acid and ascorbic acid are two naturally occurring plant hormones influencing various physiological and biochemical functions in plants. The present study was aimed to evaluate the effect of salicylic acid (SA) and ascorbic acid (ASC) on essential oil content and compositions of dragonhead (Dracocephalum moldavica L.) under application and non-application of manure. The results showed that application of SA+ ASC significantly increased the essential oil content and essential oil yield compared to control plants. The application of 20 ton/ha farmyard manure increased essential oil content and essential oil yield by 19.2 and 56.8%, respectively. According to the results, essential oil compositions were affected by foliar application of SA and ASC under manure application. The main compositions of dragonhead were geranyl acetate (28.32-47.45%) and geraniol (13.02-25.09%) followed by (Z)-citral (6.6-15.63%), (E)-citral (5.56-15.24%) and neryl acetate (5.1-8.82%). Geranyl acetate was significantly increased with SA and ASC spray under farmyard manure application, so that the highest geranyl acetate percentage was obtained in the plants treated with SA + ASC under 20 ton/ha farmyard manure (47.45%), followed by ASC under 0 ton/ha farmyard manure (41.39%). Geranial as the second main compound in the essential oil was decreased with two latter treatments (46.1 and 38.1%, respectively), compared to control. The results of this study clearly showed that SA and ASC can affect the dragonhead essential oils and its compositions, and they can be used for enhancing or improving the essential oil content and some compositions of dragonhead in an organic agricultural system.

The objective of this research was to evaluate the effect of successive harvesting times and shading on the production of biomass, yield and phytochemical composition of essential oil in leaves and inflorescences of soilless grown Lavandula dentata. Plants were grown in pots filled with sand, inside a polyethylene greenhouse, in a closed system at UFSM. Plants were harvested at 150, 213 and 320 days after planting date (DAP) in winter, spring and summer, respectively. At 150 DAP, a 50% shading screen was installed. The experimental design was a randomized 3x2 factorial in subdivided plots with 36 plants per subplot. Fresh (FM) and dry mass (DM), yield and chemical composition of essential oil in leaves and inflorescences were determined after each harvest date. The essential oil was extracted, using 70 g fresh mass of leaves and of inflorescences, respectively. Identification and quantification of compounds in the essential oil were determined by gas chromatography/mass spectrometry (GC/MS). The FM of inflorescences was higher on plants harvested 213 DAP grown without shading while of leaves it was higher on plants harvested 320 DAP grown without shading. The yield of the essential oil was higher in the leaves of plants harvested 320 DAP grown without shading. Thirty-one compounds were identified and quantified, being the major ones 1.8 cineol, camphor and linalool, without significant difference among treatments. Three consecutive harvests can be made in August (150 DAP), October (213 DAP) and February (320 DAP) without replacing plants.

Satureja pilosa Velen. senso lato is a Balkan endemic plant that is not well characterized and is found on rocky outcrops of limestone base in Stara Planina (the Balkan Mountains) and the Rhodope Mountains. The objective of this study was to assess the variability of essential oil (EO) content and composition of S. pilosa collected at 33 locations across the Balkan and Rhodope Mountains in Bulgaria using advanced statistical methods including cluster analysis. The EO content in dried aboveground biomass varied from 0.52% to 2.03%. More than 21 EO constituents were identified, belonging to the groups of monoterpenes and sesquiterpenes. The monoterpenes were the predominant class, comprising 84.8% to 96.1% of the total EO. Thymol and carvacrol were the major constituents of the phenolic monoterpenoids. Thymol varied from 36.6% to 67.1% and carvacrol varied from 52.4% to 93.0% of the total oil. p-Cymene also varied widely, from 9.6%–34.0%. There were significant variations between locations and within a location in the EO content and composition. This study identified several chemotypes: (1) thymol and p-cymene; (2) thymol, p-cymene and γ-terpinene; (3) carvacrol and p-cymene; (4) carvacrol, p-cymene and γ-terpinene; and (5) carvacrol. This is the first comprehensive study on the endemic plant S. pilosa that identified several chemotypes based on the EO composition. The S. pilosa EO from the five different chemotypes exhibited larvicidal and mosquito repellent activity against Aedes aegypti. The identified chemotypes can be utilized for the development of new varieties with desirable compositions to meet specific industry needs and new mosquito management control products.