Utjecaj uvjeta uzgoja i dodatka soli na sastav eteričnog ulja slatkog mažurana (Origanum majorana) iz Tunisa

O. majorana shoots were investigated for their essential oil (EO) composition. Two experiments were carried out; the first on hydroponic medium in a culture chamber and the second on inert sand in a greenhouse for 20 days. Plants were cultivated for 17 days in hydroponic medium supplemented with NaCl 100 mmol L1. The results showed that the O. majorana hydroponic medium offered higher essential oil yield than that from the greenhouse. The latter increased significantly in yield (by 50 %) under saline constraint while it did not change in the culture chamber. Under greenhouse conditions and in the absence of salt treatment, the major constituents were terpinene-4-ol and trans-sabinene hydrate. However, in the culture chamber, the major volatile components were cis-sabinene hydrate and terpinene-4-ol. In the presence of NaCl, new compounds appeared, such as eicosane, spathulenol, eugenol, and phenol. In addition, in the greenhouse, with or without salt, a very important change of trans-sabinene hydrate concentration in EO occurred, whereas in the culture chamber change appeared in cis-sabinene hydrate content.U radu je opisano ispitivanje sastava eteričnog ulja izdanaka biljke O. majorana. Provedena su dva eksperimenta: prvi na hidroponom mediju u komorama za uzgoj, a drugi na inertnom pijesku u stakleniku tijekom 20 dana. Biljke su uzgajane 17 dana u hidroponom mediju u koji je dodan NaCl 100 mmol L1. Rezultati ukazuju na to da hidroponi medij O. majorana osigurava veće prinose eteričnog ulja nego staklenik. U stakleniku se prinos ulja značajno povećao dodavanjem 50 % soli dok u uzgoju u uzgojnoj komori nije bilo promjene. U uvjetima u stakleniku i u odsutnosti soli, najvažniji sastojci ulja bili su terpinen-4-ol i trans-sabinen hidrat, dok su u uvjetima uzgojne komore najvažnije hlapljive komponente bile cis-sabinen hidrat i terpinen-4-ol. U prisutnosti NaCl-a, pojavili su se novi sastojci, kao što su eikozan, spatulenol, eugenol i fenol. Dodatno je uz stakleničke uvjete, sa i bez soli, došlo do važne promjene u količini trans-sabinen hidrata u eteričnom ulju, dok se u komorama promijenio sadržaj cis-sabinen hidrata

Changes in the antioxidative systems of Ocimum basilicum L. (cv. Fine) under different sodium salts

The effects of different sodium salts on some physiological parameters and antioxidant responses were investigated in a medicinal and aromatic plant, Ocimum basilicum L. (cultivar Fine). Plants were subjected to an equimolar concentration of Na2SO4 (25 mM) and NaCl (50 mM) for 15 and 30 days. Growth, oxidative stress parameters [electrolyte leakage, peroxidation, and hydrogen peroxide (H2O2) concentration], antioxidant enzyme activities [ascorbate peroxidase (APX, EC 1.11.1.11), glutathione reductase (GR, EC 1.6.4.2), and peroxidases (POD, EC 1.11.1.7)], as well as antioxidant molecules [ascorbate and glutathione] were determined. The two salts affected leaf growth rates to the same extent, after 15 or 30 days of treatment, indicating a similar effect of Na2SO4 and NaCl salinity on growth, even if different (enzymatic and non-enzymatic) antioxidant mechanisms were involved in H2O2 detoxification. However, under both salts, the efficiency of the antioxidant metabolism seemed to be sufficient to avoid the deleterious effects of reactive oxygen species (ROS). Indeed, both ion leakage and peroxidation did not change under either Na2SO4 or NaCl salinity. As a whole, these data suggest that a cooperative process between the antioxidant systems is important for the tolerance of Ocimum basilicum L., cv. Fine to Na2SO4 and NaCl salinity

Salt effects on trichome density in Ocimum basilicum L. leaves

Effects of equimolar concentrations of NaCl and Na2SO4 on trichome morphology and distribution were studied in Ocimum basilicum. Plants were treated with high salinity for 15 days. Under control conditions, four types of trichomes were observed, two non glandular trichomes (NGT, bicellular or multicellular) and two glandular trichomes (GT; peltate, P and capitate, C). In contrast with P, NGT were more represented on the adaxial than on the abaxial leaf side whereas the density of C ones was not significantly affected by the surface. Under salinity conditions, the density of P trichomes increased if plants were treated with 50 mM NaCl whereas an opposite pattern was observed following 25 mM Na2SO4 treatment. Changes in GT density under salinity was correlated with their role in essential oil production. However, the density of C, which is not considered being involved in this role, decreased regardless to the type of salt administered

Antioxidative responses of Ocimum basilicum to sodium chloride or sodium sulphate salinization

Soils and ground water in nature are dominated by chloride and sulphate salts. There have been several studies concerning NaCl salinity, however, little is known about the Na2SO4 one. The effects on antioxidative activities of chloride or sodium sulphate in terms of the same Naþ equivalents (25 mM Na2SO4 and 50 mM NaCl) were studied on 30 day-old plants of Ocimum basilicum L., variety Genovese subjected to 15 and 30 days of treatment. Growth, thiobarbituric acid reactive substances (TBARS), relative ion leakage ratio (RLR), hydrogen peroxide (H2O2), ascorbate and glutathione contents as well as the activities of ascorbate peroxidase (APX, EC 1.11.1.11); glutathione reductase (GR, EC 1.6.4.2) and peroxidases (POD, EC 1.11.1.7) were determined. In leaves, growth was more depressed by 25 mM Na2SO4 than 50 mM NaCl. The higher sensitivity of basil to Na2SO4 was associated with an enhanced accumulation of H2O2, an inhibition of APX, GR and POD activities (with the exception of POD under the 30-day-treatment) and a lower regeneration of reduced ascorbate (AsA) and reduced glutathione (GSH). However, the changes in the antioxidant metabolism were enough to limit oxidative damage, explaining the fact that RLR and TBARS levels were unchanged under both Na2SO4 and NaCl treatment. Moreover, for both salts the 30-day-treatment reduced H2O2 accumulation, unchanged RLR and TBARS levels, and enhanced the levels of antioxidants and antioxidative enzymes, thus achieving an adaptation mechanism against reactive oxygen species

Effects of NaCl and Na2SO4 salinity on plant growth, ion content and photosynthetic activity in Ocimum basilicum L.

Basil (Ocimum basilicum L., cultivar Genovese) plants were grown in Hoagland solution with or without 50 mM NaCl or 25 mM Na 2SO 4. After 15 days of treatment, Na 2SO 4 slowed growth of plants as indicated by root, stem and leaf dry weight, root length, shoot height and leaf area, and the effects were major of those induced by NaCl. Photosynthetic response was decreased more by chloride salinity than by sulphate. No effects in both treatments on leaf chlorophyll content, maximal efficiency of PSII photochemistry (F v/F m) and electron transport rate (ETR) were recorded. Therefore, an excess of energy following the limitation to CO 2 photoassimilation and a down regulation of PSII photochemistry was monitored under NaCl, which displays mechanisms that play a role in avoiding PSII photodamage able to dissipate this excess energy. Ionic composition (Na +, K +, Ca 2+, and Mg 2+) was affected to the same extent under both types of salinity, thus together with an increase in leaves Cl -, and roots SO 4 2- in NaCl and Na 2SO 4-treated plants, respectively, may have resulted in the observed growth retardation (for Na 2SO 4 treatment) and photosynthesis activity inhibition (for NaCl treatment), suggesting that those effects seem to have been due to the anionic component of the salts

Effects of oxidative stress caused by NaCl or Na2SO4 excess on lipoic acid and tocopherols in Genovese and Fine basil (Ocimum basilicum)

With this investigation, we aimed to study more deeply the antioxidative response to moderate doses of NaCl or Na2SO4 in two cultivars of basil differentially sensitive to salinity. Tolerance to salinity was previously evaluated by the extent of growth inhibition whereas the antioxidant response was assessed studying the changes in the activities of superoxide dismutase (SOD) and catalase as well as in the amounts of tocopherols and lipoic acid. To make possible the comparison of the responses of basil cv. Genovese and cv. Fine to different salts, the experiment was carried out with equimolar concentrations of Na+. The results showed that changes caused by salinity were dependent on cultivar and exposure time. In particular, cv. Genovese was more sensitive to Na2SO4 excess than cv. Fine whereas both of them had higher SOD activity under NaCl salinity. Generally, Fine basil withstood salinity better than Genovese, being endowed with higher constitutive levels of reduced lipoic acid [dihydrolipoic acid (DHLA)] as well as of α- and γ -tocopherols. Moreover, cv. Fine showed the ability to utilise DHLA and to synthesise tocopherols during stressful conditions. Thus, more than one mechanism was involved in basil in the detoxification of reactive oxygen species during salt stress. In fact, when lipoic acid did not participate in the regeneration of reduced ascorbate and glutathione form, high amounts of tocopherols were present, likely protecting cell membranes from oxidative damage and making basil tolerant to moderate salinity

Essential oil and volatile emissions of basil (Ocimum basilicum) leaves exposed to NaCl or Na2SO4 salinity

The volatile compounds emitted by living leaves of basil (Ocimum basilicum L. cv. Genovese) plants under saline conditions were investigated by means of headspace–solid phase microextraction (HS-SPME) and gas chromatography coupled with mass spectrometry (GC–MS). Furthermore, the composition of the essential oil obtained by hydrodistillation of the leaves was studied. Plants were grown for 15 d without salt or with an equimolar concentration of Na+ in the form of Na2SO4 (25 mM) and NaCl (50 mM), after which the growth, the essential oil, and the volatile constituents of the leaves were determined. Fifty-four components were identified belonging to different chemical classes. Under control conditions, the essential oil was rich in linalool (45.9%), 1,8-cineole (16.7%), eugenol (10.3%), trans-α-bergamotene, and epi-α-cadinol (4.9%). The main volatiles detected in the headspace of leaves of untreated basil plants were linalool (29.8%), followed by 1,8-cineole (19.2%), trans-α-bergamotene (10.0%), and eugenol (7.0%). Under saline conditions, leaf growth was more depressed by 25 mM Na2SO4 than 50 mM NaCl, and essential oil concentration increased by 22% in the NaCl, but decreased by 18% in the Na2SO4 treatment, respectively. Both salts caused some changes in the essential oil and composition of volatile compounds. Most prominent was a strong negative correlation between eugenol and methyleugenol proportions, which may indicate an enhancement of the O-methyltransferase activity. In comparison to the essential oil, the composition of volatiles showed some variations in their emission profile under both salts, the most important was an increase of eugenol. It is therefore concluded that the decrease of eugenol occurring in basil essential oil caused by both salts could be due to the enhancement of the eugenol O-methyltransferase activity, an enzyme that accepts eugenol as substrate, generating methyl eugenol, and also to the increase of the eugenol emission as shown by the SPME profil