Lavandula luisieri

ABSTRACT This study forms part of a larger multidisciplinary environmental study of the Lower Guadiana River basin carried out by a joint Portuguese-Spanish research team. It describes the mobility of lead in soil profiles taken over varied lithologies of the Iberian Pyrite Belt and the distribution of this metal with the root, stems and leaves of three plant species native to the area (Cistus ladanifer L., Lavandula luisieri and Thymus vulgaris). Results indicate that at all sample sites the mobility of lead is very low. 

The Guadiana Basin occupies a total area of 66,850 km2 in Spain and Portugal, 8,350 km2 of which comprises the Iberian Pyrite Belt (IPB) one of the world s largest concentrations of base metal sulphide deposits (Leistel et al., 1997 Ribeiro et al., 1990). Three plant species (Cistus ladanifer, Lavandula luisieri and Thymus vulgaris) were utilized in this study. The soils in which these plants were sampled are developed over varied geological formations. The oldest formation (PQ Group, Upper Devonian) consists of a thick sequence of arenites and shales... 

The concentrations of lead in plants are in general higher in the roots than in the aerial parts (stems and leaves), with 25 to + 5000 mg kg 1 and 11 to 15 mg kg"1, respectively in Lavandula luisieri (Rozeira) Rivas-Martinez roots and aerial parts 3 to982 mg kg"1 and 3 to 308 mg kg 1, respectively in Cistus ladaniferL. roots and aerial parts and 35 to 70 mg kg 1 and 8 to 29 mg kg"1, respectively in Thymus vulgaris L. roots and aerial parts. 

DHS applications have been developed, for example, for the determination of aroma-active compounds in bamboo shoots (83), styrene in yoghurt (8- ) and volatile acids in tobacco, tea, and coffee (88), volatile compounds of strawberries (89) and odor-active compounds of hams (90). The applications of DTD-GC include, for example, in the determination of volatile components of Lavandula luisieri (85), in the analysis of volatile components of oak wood (87) and volatiles in various solid-food products such as spices and herbs (black pepper, oregano, basil, garlic), coffee, roasted peanuts, candy and mushrooms (82). 

An example of a DHS application is the determination of aroma-active compounds in bambuu shoots. In this study, compoimds such as p-cresol, methional, 2-heptanoI, acetic acid, ( ,Z)-2,6-nonadienal, linalool, phenyl acetaldehyde, were extracted from the bambuu shoot samples and analysed by GC. The required sample amount was 10 g, and the extraction temperature was 60°C, using a 30 min extraction time. The stripped analytes were first trapped into a cooled adsorbent tube (VOCARB 3000, at 0 °C), and then thermally desorbed to GC. In DTD, the sample amount required for the analysis is typically smaller than in solid head-space (SHS). In the determination volatile components such as camphor, 1,8-cineoIe and 2,3,S,S-tetramethyl-4-methylene-2-cyclopenten-l-one, from Lavandula luisieri, only 10-20 mg of (dry) plant sample was required for the analysis. The volatiles were desorbed fi om the sample under a helium flow and then cryofocused on a Tenax TA trap at -30 °C. The trap was then quickly heated and the desorbed volatiles were transferred directly to the GC column through a heated fused-silica line (85). 

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