Arnaldo Codignola

Photosynthesis, Photorespiration and Herbicide Effect on Terpene Production in Peppermint (Mentha piperita L.).

ABSTRACT To look for the possible influence of photosynthesis and photorespiration on terpene metabolism in peppermint (Mentha piperita L.), the volatile oil composition in the peltate glandular trichomes was estimated in relation to: 1, 5-Ribulose bis-phosphate carboxylase (RuBP-case) and glycolate oxidase (GO) activities. Total protein and chlorophyll content and chorophyll a/b ratio values were also estimated and correlated with the oil composition. The chloroplast ultrastructure, some chloroplast morphometrical parameters and the photorespiratory organelle complex (mitochondrion-microbody-chloro-plast) ultrastructure were also studied. The effect of 3–3, 4(Dichlorophenyl)-1,1-dimetlrylurea (DCMU) and 1, 1′-Dimethy 1–4, 41-bipyridinium dichloride (Paraquat) on oil composition was tested on peppermint leaf discs. The percentage of monoterpene alcohols and esters increased, along with RuBP-case and GO activities, with leaf age, while the percentage of monoterpene ketones and the Chl a/b ratio decreased. ...

Essential oils and chromosome numbers from Italian Achillea species

ABSTRACT Essential oils of five Achillea species, A. ptarmica, A. erba-rotta, A. moschata, A. nana and A. nobilis, growing spontaneously in the Northwest Italian Alps were analyzed by gas chromatography-mass spectrometry. Several monoterpenes, sesquiterpenes and phenols were identified. Camphor and 1,8 cineole were the major constituents of A. erba-rotta, whereas germacrene D was particularly abundant in A. ptarmica and A. nobilis. A. moschata oil contained mainly terpinen-4-ol whereas trans- and cis-isoeugenol were present in good percentages in A. nana. The caryological analyses revealed a diploid (2n = 18) chromosome number for all plants. The absence in the essential oil of proazulene compounds was related to the diploid (2n = 18) chromosome number of the above mentioned species.

Fatty acid variability in some Mentha hybrids

Abstract Fatty acids from aerial parts of some Mentha x verticillata hybrids were analysed. Data showed an evident intraspecific variability with high 18:3, high 16:0 and intermediate 16:0–18:3 chemotypes.

Photosynthetic enzyme activities in lemongrass cultivated in temperate climates

Abstract Phosphoenolpyruvate carboxylase and RuBP carboxylase activities and Δ 13 C values were measured in lemongrass. The values obtained range among those typical of C 4 plants. The glycolate oxidase activity can be correlated to the usual low C 4 photorespiratory levels. The high chlorophyll a/b ratio is also consistent with a high efficiency photosynthesis. It is evident that Cymbopogon citratus , even though cultivated in climates colder than those of its origin, may possess a C 4 photosynthetic mechanism.

Variazioni stagionali del contenuto di fenoli in gemme di Betula alba L

Abstract Phenols seasonal variations in Betula alba L. buds. - Estimation of the seasonal variations in the totals endogenous phenols levels in Betula alba L. buds is given. From november to march phenolics concentration is high and uniform; after a little decrease at the end of march, dormancy period break is associated with a rapid abatement of their level. Parallely the AA. develope a phenolics chromatografic separation on dextran gel; all the fractions reveal the same variations trend of the total phenols. U.V. spectrophotometric analysis of the most important fraction suggests she could be quercitrin. These chemical researchs show a certain parallelism between phenols level variations and dormancy course.