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.

Four kinds of fresh sweet oranges were obtained in the same season, November 2000, in Guangzhou. Citrus sinensis var. Hongjiang (called 'hong jiang chen' in Chinese) and C. sinensis Osbeck var. Anliu (called 'luo gang chen') were obtained at an orchard in Luo gang in Guangzhou (25 km from the center of Guangzhou). Citrus sinensis var. Sihui (called 'sihui ju') was harvested at the Shigou Experimental Farm in Sihui City in Guangdong Province (75 km far away from Guangzhou). Citrus sinensis var. Washington navel (called 'qi chen') which was produced in Jiangxi Province (200 km from Guangzhou; bordering Guangdong Province), was purchased at the wholesale market in Guangzhou. All oranges were kept in a cold room until prepared a few days later.

The peel oil compositions of four kinds of sweet oranges in China, Citrus sinensis Osbeck var. Hongjian, C. sinensis Osbeck var. Anliu, C. sinensis Osbeck var. Sihui and C. sinensis Osbeck var. Washington navel, were investigated by GC and GC/MS. The essential oils were extracted by cold-pressing method. Forty-two to 53 compounds were quantitatively determined for each variety. Their percentages, respectively, were: > 97.3%, > 98.4%, > 97.5% and > 98.0% in hydrocarbons; > 1.5%, > 0.7%, > 0.8% and > 0.9% in total aldehydes; 0.8%, 0.5%, 0.5% and 0.5% in alcohols. Either cis-or trans-limonene oxide was detected in small amounts in each of the four samples, with Hongjiang containing both limonene oxides. delta-3-Carene was commonly quantified at a level of 0.1% in all the samples. The content of aliphatic aldehydes, including octanal, nonanal, decanal and dodecanal, exceeded that of terpene aldehydes, such as neral and geranial in Hongjiang (0.9%) and Washington navel (0.6%), whereas the aliphatic aldehydes in Anliu and Sihui were present to a lesser degree than the terpene aldehydes. Either alpha- or beta-sinensal was detected in trace amounts in each of the four samples. Linalool was the major alcohol in all the samples. Nootkatone was not detected.

The aerial parts (~35 cm) of each taxa growing wild in eight localities of Almeria province were collected in May 1996. All samples were collected at full flowering. Sideritis pusilla (Lange) Pau ssp. pusilla var. typica, Population/location (UTM): Los Matarines (30SWF7992); Sideritis pusilla ssp. pusilla var. carthaginensis Font Quer, Population/location (UTM): Rambla del Hacho (30SWF7178); Sideritis pusilla ssp. pusilla var. granatensis (Pau) Font Quer, Population/location (UTM): Gafarillos (30SWG8702); Sideritis pusilla ssp. almeriensis (Pau) Malagarriga var. typica, Population/location (UTM): Sierra de Gador, Cerro de los Lobos (30SWF3575); Sideritis pusilla ssp. almeriensis var. littoralis Font Quer, Population/location (UTM): Los Morales (30SWF6775); Sideritis pusilla ssp. almeriensis var. salina Font Quer, Population/location (UTM): Los Pedregales (30SWG7835); Sideritis pusilla ssp. flavovirens (Rouy) Malagarriga, Population/location (UTM): Velez Rubio, Cerro del Huezno (30SWG8965); Sideritis pusilla ssp. osteoxylla (Pau) Pallares, Population/location (UTM): Cabo de Gata, Cerro de S. Miguel (30SWF7165)

Monoterpene hydrocarbons, alcohols, sesquiterpenes and diterpenes were the main constituents in all samples. Among these, alpha-pinene (7.1-25.4%), sabinene (5.9-20.4%), fenchone (0.9-19.3%), limonene (1.2-7.4%) and 1,8-cineole (1.8-15.6%) were the major compounds. The results confirm that there are differences between varieties and subspecies, while cluster analysis revealed that the oil composition potentially has chemotaxonomical significance for this taxon.