In vitro cultivation of Arabidopsis wildtype and mutant plants: Seeds were sterilized according to standard lab routines (EtOH, NaOCl/NaOH) prior to aseptical (in vitro) cultivation in 500 ml screw cap jars on MS medium (4.3 g/l; 50 ml/jar) containing Bacto- and Phytoagar (1:2; 6 g/l) and 30 g/l sucrose. Ten seeds were pipetted into each jar and plants grown for 6 weeks until flowering at a temperature of 20 ℃ under a 16/8 h day/ night regime using fluorescent tubes (Osram Lumilux Plus Eco 36 W). Both Arabidopsis thaliana wildtype plants of ecotype Columbia-0 (Col) and 4 Col-derived T-DNA knock-out mutants (homozygous lines) showing deficiencies in the GLS biosynthesis pathway were used in this study (five parallels for wildtype and mutants): TGG1 (Atg526000; Salk_130469), TGG2 (At5g25980; Salk_038730), Cyp83A1 (At4g13770) and Cyp83B1 (At4g31500; Salk_028573). Greenhouse-cultivation of Arabidopsis ecotypes: The following Arabidopsis ecotypes were used in the study: Columbia (Col), Cape Verde Islands (Cvi), Landsberg erecta (Ler) and Wassilewskija (Ws). Single plants were greenhouse-cultivated on fertilized soil (P-Jord; Emmaljunga Torvmull AB) in plug trays (9 × 6 cells) at a temperature of 20 ℃ (three parallels for each ecotype). Due to the 6-weeks growth period (November/December 2003), the plants were cultivated under a 16/8 h day/night regime using metal halide lamps (Osram HQI-T 400 W) placed 130 cm above the trays. Depending on the ecotypical plant development, whole plants were sampled after 3-4 weeks right before bolting for in vivo studies, while investigations of single plant organs (leaf, stem, inflorescence) were carried out after 5-6 weeks of cultivation.

Metabolites from methionine, leucine and phenylalanine-derived glucosinolates were most abundant (4-methylthiobutyl, 4-methylpentyl, 2-phenylethyl). In addition, 24 monoterpenes, 26 sesquiterpenes and 12 aromatic structures, predominantly observed in inflorescenses, are described. Excluding the vast group of straight chain aliphatic structures, a total of 102 volatile compounds were detected, of which 59 are reported in Arabidopsis thaliana for the first time, thus emphasizing the sensitivity and applicability of solid-phase microextraction for volatile profiling of plant secondary metabolites.

Ten different plants of wormwood were collected in March 1997 from each one of the following four wild populations in the Spanish Pyrenees: Tallo de Aulet (prov. Huesca) and Pont de Suert, Sort and Farga de Moles (prov. Lleida). In three of the four populations studied, there was another chemotype, with 25-65% of cis-epoxyocimene and 15-50% of chrysanthenyl acetate. This chemotype, called chemotype B, was less frequent in the Pyrenees than the chemotype A, appearing only in 17% of the samples (two samples in TallO de Aulet and in Pont de Suert and three samples in Farga de Moles).

Two chemotypes were detected; a cis-epoxyocimene type (with more than 50% of this compound) which was predominant in all the populations, and a cis-epoxyocimene + chrysanthenyl acetate type (with 25-65% of cis-epoxyocimene and 15-50% of chrysanthenyl acetate). The distribution of these chemotypes had no relation with the altitude of the samples.

Populations of A. annua cultivar 'Jeevanraksha' and accession Suraksha were grown in the experimental field plot of the Institute at New Delhi. The seeds were sown in January 2004, seedlings transplanted in late February 2004 and aerial parts (flowers, leaves and stems from the upper 0.5 m of crop canopy) sampled in late October 2004.

Ninety-seven compounds comprising 91.3% of the total oil of 'Jeevanraksha' were identified. Forty-three monoterpenes (56.6%), 32 sesquiterpenes (31.1%), and 2 diterpenes (0.2%) comprised bulk of the oil (87.9%). The oil was devoid of artemisia ketone and contained camphor (13.5%), 1,8-cineole (9.4%), trans-sabinol (7.1%), p-mentha-1(7), 5-dien-2-ol (6.3%), myrcene (4.7%), germacrene D (4.4%), (E)-beta-farnesene (3.9%), beta-caryophyllene (3.7%), dihydroartemisinic lactone (3.0%) and p-cymene (2.0%) as the major constituents. Eighty-six compounds representing 93.3% of the composition were identified in the Suraksha oil. This oil contained artemisia ketone (47%), 1,8-cineole (8.4%), camphor (5.9%) and alpha-pinene (5.2%) as the major components.

Plant material of A. verlotiorum was harvested near Marseille (France) in May (before blooming) and November (full flowering) 2000.

For the oil from the vegetative plants, 50 compounds, representing 99.8% of the oil were characterized. Fifty-nine compounds, representing 99.6% of the oil were identified in the oil from flowering plants. In both cases, the constituents were mainly oxygenated monoterpenes (74% and 88%). The composition of each oil showed only a few differences, as the main components were alpha-thujone (55% and 44%), 1,8-cineole (5% and 15%), beta-caryophyllene (13% and 7%) and beta-thujone (5% and 11%), in the oils of the vegetative plant and flowering plant, respectively. The proportions of the oxygenated compounds seemed to increase during flowering.

Plant material: Coriander (Coriandrum sativum L.) fruits were collected from cultivated plants in the region of Korba (northeastern Tunisia) in April 2006. Seeds were set to germinate at 25 ℃. Ten-day-old coriander seedlings were grown in quarter-strength Hoagland's solution laced with 0 mM, 25 mM, 50 mM and 75 mM of NaCl. The culture was placed in a greenhouse with 25 ℃ day maximum and 18 ℃ night minimum, under artificial light of 141 µmol/m² /s (6000 lux) with 16 h photoperiod and 60-80% air humidity. Nutrient solution was continuously aerated. Growth parameters: Plants were harvested at the seedling stage 3 weeks after treatment.

Essential oil content was 1762.64 µg/g dry weight (DW) (0.18%) and 1255.77 µg/g DW (0.12%) in stems and leaves, respectively. At low and moderate stress, a significant difference in the essential oil content was developed between stems, with a significant decrease, and leaves, with an increase up to 43%. Under high salinity, the oil content of both organs decreased significantly. The major volatile compound of stems and leaves was (E)-2-decenal with 24% and 52%, respectively. Other important components were decanal, (E)-2-dodecenal, dodecanal, (E)-2-undecenal, (E)-2-tridecenal and (E)-2-undecanal. Further, the content of these compounds were affected differently by the treatment level and by the organ type.

The aerial parts of D. assadii Alava. were collected in the wild from Lalehzar (Kerman Province, in southern Iran) at the flowering stage, in July 2007. The material was dried at room temperature and used for distillation. Distillation: A direct-fired field distillation unit containing a distillation tank (capacity: 1,000 L), a condensation column and receiver, all made of stainless steel, and which can process 30-50 kg of dried aerial parts from the plants/batch, was installed at an altitude of 2600 m (boiling point: 87 ℃). Dried aerial parts from the plants (40 kg) were charged into the distillation unit along with 500 L fresh water and the unit was heated by steam. The system was kept open to atmospheric pressure until the temperature reached to 70 ℃, when the air present in the unit was replaced by the vapor. After complete removal of air from the unit, the air vent was closed and the whole unit was operated as a closed system under pressure to distill the oil. The pressure, temperature and rate of distillation were controlled manually. The process was completed after the collection of 500 L of water distillate. The oil collected in the receiver and dried over anhydrous Na₂SO₄. Extraction of Ducrosia Second Oil From Ducrosia Water by Redistillation: The seprated distillate water collected in the receiver was redistilled in a 1,000 L still to yield more Doucrosia oil (this oil is known as secondary essential oil, second oil, cooked oil or indirect oil).

Fifty components were identified in a second oil of D. assadii from Lalehzar with decanal (35.2%), nonadecane (12%) and citronellyl acetate (11.6%) as the main constituents. The oil from Dehbakrii also contained decanal (36.4%) as the main component of an oil recovered from the distillate water. The results showed that the amount of decanal is remarkably high in the oils of D. assadii.

Plant material: Samples of L. latifolia were collected in August 1998 during the full flowering period (L/La) and in October 1998 during the fruiting period (L/Lb) from three different spike lavender populations located into the Cazorla, Segura y Las Villas Natural Park (Jaen province, Spain). The plant material from each population consisted of the twigs of several single plants. L/La (Location: 'Garganta de Hornos', Altitude (m): 950, Harvesting date: August 14, 1998, Phenological stage: Flowering); L/Lb (Location: 'Garganta de Hornos', Altitude (m): 950, Harvesting date: October 15, 1998, Phenological stage: Fruiting).

The small amounts of linalool needed to match the standard can be reached in a natural way (from full flowering to fruiting) which means it is important to choose the most convenient time of harvest in the studied area.

The peppermint material was obtained from ten cultivation sites (four growers) around Le Mayetde-Montagne, Allier, France (altitude 400 to 800 m). The individual surface areas ranged from 0.6 to 2.5 ha for an overall surface of 8 to 10 ha. Planting density was 30,000 plants/ha.

A marked inversion of the menthol/menthone ratio was observed according to harvesting time. The late blooming period gave oils rich in menthol. A second harvest gave a high-quality oil and increased overall yield. Pre-drying did not affect the chemical composition of the oil obtained but allowed larger amounts of plant material to be distilled. In particular, Bouverat-Bernier showed an increase in oil yield up to flowering and a fall thereafter and an increase of levels of menthol and menthyl acetate while those of menthone decreased from June to September. For Hungarian peppermint, the levels of menthone were always greater than those of menthol regardless of harvest time.

The aerial parts of M. biflora collected during November 1993 and June 1994 were used for the investigation.

The major constituents of the oil were neral (25.3-32.2%) and geranial (26.7-41.3%). The oil produced in the winter was found to contain higher amounts of oxygenated monoterpenes than the oil produced in the summer.

Myrtle (M. communis var. italica) aerial parts were collected monthly during 2006-2007 from Jbal Stara of Haouaria region in North Tunisia, belonging to a subhumid bioclimate.

In conclusion, high fluctuations were observed in the oil yields and composition of different parts of Myrtus communis var. italica during all the collecting periods. They could be explained by genetic and environmental factors. Moreover, significant differences were revealed in the main oil compounds. alpha-Pinene percentages showed the most remarkable changes among the different part oils. So, leaf oils contained more alpha-pinene than those of the fruits and stems during the myrtle vegetative cycle.

Biological material for these investigations comes from two distant collection sites: Suva planina (mountain in the east of Serbia) and Durmitor (mountain in Montenegro). All specimens (aerial parts of the plants) were collected in 1994 in the blooming stage and/or in the pre-blooming stage.

The results obtained show that though the yields of oils were barely influenced by plant growth stage, they varied appreciably according to the origin of the plant material: pre-blooming, Suva Planina (Serbia): 0.67%; blooming, Suva Planina (Serbia): 0.70%; blooming, Durmitor (Montenegro): 0.40%. Thirty-six components were identified. 1,8-Cineole was always predominant (60%); its concentration was lower (40%) just before blooming. Also present were germacrene D (2-15%), beta-caryophyllene (4-7%), alpha-terpineol (5-7%) and caryophyllene oxides (2-6%). In general, the chemical composition of N. nuda depended more strongly on growth stage than habitat. The only exception was caryophyllene oxide which was three times more abundant in the oil from Montenegro than in that from Serbia.

Field experiment was initiated in June 2000 in the same block of the research farm. The experiment was laid out in a randomized block design with five treatments on stage of crop harvest (pre-flowering and 25%, 50%, 75% and 100% flowering) and four replications, individual plots being 3 × 6 m. Each plot received uniform dose of neem cake 900 g (0.5 t/ha), di-ammonium phosphate 155 g (40 Kg P₂O₅ /ha) and muriate of potash 120 g (40 kg K₂O/ha) as basal dose which was incorporated with 5 cm top soil using hand hoe. Ocimum gratissimum seedlings, six weeks old, were planted at 60 cm row-to-row and 45 cm plant-to-plant spacing in June 2000. The field was irrigated immediately after planting for early establishment of the seedlings. Thereafter, the field was irrigated 11 and 13 times in the first and second year of experimentation, respectively. Nitrogen at 120 kg/ha was applied in the form of urea spreading over all the harvests per annum. The crop received fi ve and four hand weedings during first and second year of experimentation. Apical part (25-35 cm) of all the branches was harvested in all the treatments as given below: (Pre-flowering Year1 September 20 and November 12, 2000 and January 16, March 17 and May 16, 2001; Year2 July 20, September 13 and November 17, 2001 and January 27, April 7 and June 16, 2002); (25% flowering Year1 September 26 and November 25, 2000 and February 3, April 9 and June 13, 2001; Year2 August 17, October 16 and December 26, 2001 and March 11 and May 25, 2002); (50% flowering Year1 September 30 and December 4, 2000 and February 17, April 28 and July 7, 2001; Year2 September 10 and November 14, 2001 and January 24, April 9 and June 23, 2002); (75% flowering Year1 October 7 and December 16, 2000 and March 6 and May 20, 2001; Year2 August 3, October 12 and December 21, 2001 and March 6 and May 25, 2002); (100% flowering Year1 October 15 and December 29, 2000 and March 24 and June 12, 2001; Year2 August 31 and November 14, 2001 and January 28, April 18 and July 7, 2002).

Harvesting at pre-flowering produced 12.5%, 24.1%, 35.5% and 50.0% higher biomass yield compared to harvesting at 25%, 50%, 75% and 100% flowering, respectively, in the first year of cropping. The respective increase was 16.8%, 22.0%, 38.2% and 63.2% in the second year. Late harvested crop (100% flowering) contained the highest amount of essential oil and it decreased in the order of harvesting at 100% flowering > 75% flowering > 50% flowering > 25% flowering > pre-flowering treatment. The total oil yield was, however, significantly higher (15.8-19.9% and 12.7-33.6% in first and second years, respectively) with pre-flowering compared to all other harvest treatments. Pre-flowering harvested crop produced oil containing the highest amount of eugenol and it decreased in the order of harvesting at pre-flowering > 25% flowering > 50% flowering > 75% flowering > 100% flowering treatment.

The branches of pine were collected in July, 1996 in 15 different locations in Lithuania in the following regions: Western part (Silute, Jurbarkas, Kursiu Nerija), Eastern part (Salcininkai, Zarasai, Moletai), Southern part (Varena, Trakai, Radviliskis) and central part (Ukmerge, Jonava, Kaisiadorys). The branches in each location were collected from the trees in approximately 1 km radius.

More than 70 constituents were identified (64 positively and 10 tentatively) in the oils. alpha-Pinene (18.5-33.0%) and delta-3-carene (9.1-24.6%) were dominating constituents with the only one exception when the germacrene-4-ol content in one of the samples was 13.2%. The important bornyl acetate content varied from 0.5% to 3.0%. The main sesquiterpenes were beta-caryophyllene, germacrene D, bicyclogermacrene, delta-cadinene, gamma-cadinene, germacrene D-4-ol, cubenol (2.0-5.1%) and alpha-cadinol (1.9-7.7%).

S. aucheri var. aucheri was collected in Karaman: Ermenek to Mutt Road on July 19,1995; Salvia aucheri var. canescens was collected in Karaman: Ermenek, Tekecati Valley on July 19,1995.

Eighty components were characterized in the Salvia aucheri var. aucheri oil, with camphor (21.1%), 1, 8-cineole (20.3%), borneol (7.8%), spathulenol (6.3%) and camphene (5.3%) as major constituents. 1, 8-Cineole (25.2%), camphor (17.9%), borneol (10.6%), alpha-pinene (5.4%) and camphene (5.3%) were identified as major constituents among the 88 components characterized in the oil of Salvia aucheri var. canescens.

Plant material and isolation procedure: Aerial parts of the plant were collected from two regions, from Kazeroon in southern Iran and Shahr-e-kord in western Iran at the time of flowering in June 2002.

The main components of the oil of S. pilifera collected from Kazeroon, in southern Iran, were spathulenol (15.8%), cis-chrysanthenol (15.3%), beta-caryophyllene (8.4%) and cis-chrysanthenyl acetate (6.9%), while for the plant collected from Shahr-e-kord, in western Iran, they were cis-chrysanthenyl acetate (21.8%), linalool (18.9%), terpinen-4-ol (11.9%) and cis-chrysanthenol (9.2%).

The aerial parts of T. chamaedrys were collected at the flowering stage in June 2004 near Corti, Corsica, France and near Oristano, Sardinia, Italy

The Corsican and Sardinian oils of T. chamaedrys investigated in this study were qualitatively similar but they differed by the amount of their major components. The major components were beta-caryophyllene (29.0% and 27.4%, respectively) and germacrene D (19.4% and 13.5%, respectively), followed by alpha-humulene (6.8%) and delta-cadinene (5.4%) in the Corsican oil and by caryophyllene oxide (12.3%) and alpha-humulene (6.5%) in the Sardinian oil. These quantitative differences are also noticeable on the amounts of the different class compounds. Especially, the monoterpene hydrocarbons amounted for 10.3% and 4.1% in Sardinian and Corsican oils respectively and the oxygenated sesquiterpenes amounted for 18.9% and only 7.4% in both oils, respectively. Both oils were qualitatively rather similar in comparison with those reported in the literature from various geographic regions. However, among the 87 components identified in this study, 47 minor components (< 0.6%) reported were identified for the first time in T. chamaedrys oil. This study confirms the quantitative variability of the major components according to the plant origin.

Herbal parts were collected from A = Eskisehir: Suluagac village in Turkey, altitude 1100 m, in July 1990 and B = Corum: Osmancik, Berk village in Turkey, altitude 580-600 m, on 22 June 1993.

One chemotype (Suluagac village, Eskisehir, Turkey) contained carvacrol (21.59%), p-cymene (17.80%) and thymol (14.10%); and the other chemotype (Berk village, Corum, Turkey) contained alpha-terpinyl acetate (23.80%), borneol (12.85%), linalool (13.67%) and thymol (11.31%) as major constituents.

Plant materials were collected from the following localities in north western Turkey. A = Trabzon: Caykara, Soganli dag on July 28, 1994; B = Bayburt: Caykara, Mohakambo yaylasi on July 25, 1994; C = Trabzon: Koprubasi, Vizara yaylasi on July 20, 1994.

One hundred and four compounds were identified representing 97.5-99.5% of the total components detected in thymol/carvacrol (50.14/10.67%), thymol/linalool (23.14/20.24%) and linalool/alpha-terpinyl acetate/geraniol (21.55/16.70/11.17%) rich oils.