Micropropagation of Nolina recurvata Hemsl.: β-Cyclodextrin effects on rooting

Nolina recurvata Hemsl. is a very decorative indoor plant but difficult to micropropagate vegetatively. In vitro cuttings failed to induce adventitious rooting. Investigations for a rapid micropropagation using β-cyclodextrin added to the rooting medium has solved the problem. Rooted N. recurvata plantlets were obtained after successive stages of various culture media.Initiation and in vitro multiplication of this plant was possible with lateral buds cultured in Murashige and Skoog medium supplemented with 4.45 μmol of BA and 0.5 μmol of IBA. The number of axillary shoots by explant obtained was 6.In vitro rooting was obtained in MS medium (1/2 strength of minerals salts) supplemented with β-cyclodextrin. This substance, at 1.76 mmol associated with 5 μmol of IBA, improved quality and the rooting rate by 100%.     

Salicylic acid alleviates the toxicity of cadmium on seedling growth,amylases and phosphatases activity in germinating barley seeds

The present study investigated the possible mediator role of salicylic acid (SA) in alleviating cadmium (Cd) toxicity during the germination stage of barley. The exposure of barley seedling to increasing Cd concentrations (25, 50 and 100 µM) during early stages of their establishment, caused a gradual decrease in vigour index, root length, α-amylase, acid phosphatase, alkaline phosphatase activities in endosperms and mitotic index of the root tip. Seed pretreatment with 600 µM SA partially alleviated the negative effects of Cd on germination parameters and increased the hydrolytic enzyme activities and mitotic index. Cadmium treatment increased Cd accumulation in roots. Furthermore, results showed that compared to the cadmium treatment applied alone, SA pretreatment of the seeds did not influenced the Cd concentration in the roots. These results suggest that SA plays a positive role in barley-seed germination and early seedling growth by protecting it against Cd toxicity by moderating its toxic effect on the mobilization of organic reserves.     

Effect of drought on the biochemical composition and antioxidant activities of cumin (Cuminum cyminum L.) seeds

This study is designed to examine the yield components, fatty acid, and essential oil compositions and phenolic contents fruit essential oil composition, the total phenolic amounts as well as the antioxidant activities of cumin (Cuminum cyminum L.) seeds under drought. This plant is one of the most common aromatics in the Mediterranean kitchen. Plants were treated with different levels of water deficit: control (C), moderate water deficit (MWD) and severe water deficit (SWD). Our results indicated that MWD improved the number of umbels per plant as well as the number of umbellets per umbel and the seed yield, in comparison to the control, but it decreased under SWD. Fatty acid composition analysis indicated that petroselinic acid was the major fatty acid (55.9%) followed by palmitic (23.82%) and linoleic (12.40%) acids. Water deficit enhanced the palmitic acid percentage and affected the double bound index of the fatty acid pool and thus the oil quality. The essential oil yield was 1.64% based on the dry weight and increased by 1.40 folds under MWD. Nevertheless it decreased by 37.19% under SWD in comparison to the non treated seeds. Drought results on the modification of the essential oil chemotype from γ-terpinene/phenyl-1,2 ethanediol in the control seeds to γ-terpinene/cuminaldehyde in stressed ones. Besides, total phenolic contents were higher in the treated seeds (MWD and SWD). Results suggest that water deficit treatment may regulate the production of bioactive compounds in cumin seeds, influencing their nutritional and industrial values. Besides, antioxidant activities of the extracts were determined by four different test systems, namely DPPH, β-carotene/linoleic acid chelating and reducing power assays and showed that treated seeds (MWD and SWD) exhibited the highest activity.     

Water deficit effects on caraway (Carum carvi L.) growth, essential oil and fatty acid composition

The Mediterranean region suffers of drought which affects plant behaviour regarding biochemical responses. Accordingly, the effects of water deficit on growth, essential oil and fatty acid composition of caraway (Carum carvi L.) seeds were investigated. Plants were treated with different levels of water deficit: control, moderate water deficit and severe water deficit. Plant growth (height, fresh and dry matter weight) was significantly reduced by severe water deficit. This last caused also important reductions of the seed yield and yield components. Drought decreased significantly seed total fatty acid contents and particularly the petroselinic ones whose proportions decreased significantly by 12.17 and 18.47%, in comparison with the control, under moderate water deficit and severe water deficit, respectively. Besides, moderate water deficit increased the essential oil yield (expressed as g/100 g on the basis of dry matter weight). The main essential oil constituents were carvone and limonene which showed an increasing of their contents under water deficit levels. Thus, water deficit induced a significant reduction in growth parameters and fatty acid content, and an increase in the essential oil compounds. These bioactive compounds have been required in many industrial products.     

Variation of the amino acid scores and of the nitrogen-to-protein conversion factors in barley grain as a function of nitrogen content as compared with wheat and rye

Barley grains (9 samples from 7 cultivars) with nitrogen contents (N) ranging from 1.45 to 4.01% of dry matter were analysed for their amino acid (AA) composition with high accuracy from six different hydrolysates per sample. AA levels in grain increased as linear functions ofN with correlation coefficients close to unity. A comparison with literature data confirmed that the AA composition of any grain sample of normal barley can be predicted from itsN for all phenotypes and genotypes. AAs in grain protein changed as hyperbolic functions ofN which increased for Phe, Pro and Glx but more or less strongly decreased for the other AAs. By plotting AA scores againstN, barley proteins were shown to be always richer than wheat and rye in Val and Phe + Tyr; sometimes richer than both other species forN<2 (Lys); 2.2 (Leu and Ile); 3.4 (Thr); sometimes intermediate to wheat and rye above the latterN values. They were also intermediate in sulphur AAs forN<1.9 and drastically poorer forN>1.9. However, they were richer than both other species in Trp forN>1.6. The hyperbolic variations of non-protein nitrogen and nitrogen-to-protein conversion factors were determined as a function ofN and also compared with those of wheat and rye.     

Water-deficit impact on fatty acid and essential oil composition and antioxidant activities of cumin (Cuminum cyminum L.) aerial parts

This study is designed to examine the effect of water deficit on growth, fatty acid and essential oil composition, and antioxidant activities of Cuminum cyminum aerial part extracts. Plants were treated with different levels of water deficit: control (C), moderate water deficit (MWD), and severe water deficit (SWD). Plant growth (height, fresh and dry matter weights) as well as yield components were significantly increased under moderate water deficit and conversely reduced at severe level. Total fatty acid content decreased significantly with severity of constraint. Drought reduced considerably the proportions of major fatty acids and the unsaturated to saturated fatty acid ratio. The essential oil yield was 0.14% (based on the dry weight); it increased by 2.21-fold at MWD but decreased by 42.8% under SWD in comparison to the control. Drought results in the modification of the essential oil chemotype from 1-phenyl-1-butanol to 1-phenyl-1,2-ethanediol. Antioxidant activities of the acetone extracts were determined by two complementary test systems, namely, DPPH and β-carotene/linoleic acid. The highest activity was exhibited by moderately stressed plants and was reduced significantly under SWD. In control plants, the total phenolic amount was 10.23 mg GAE/g DW, which increased by 1.5-fold under MWD and decreased by 42% under SWD.     

Water deficit effects on Salvia officinalis fatty acids and essential oils composition

The effects of water deficit on vegetative growth, fatty acids and essential oil yield and composition of Salvia officinalis aerial parts were investigated. Plants were treated with different levels of water deficit (C, MWD and SWD). Results showed important reductions of the different growth parameters. Drought decreased significantly the foliar fatty acid content and the double bond index (DBI) degree. This later was provoked mainly by a strong reduction of linolenic acid proportion and the disappearance of palmitoleic acid. Besides, moderate deficit increased the essential oil yield (expressed as g/100 g on the basis of dry weight) and the main essential oil constituents were camphor, α-thujone and 1.8-cineole which showed an increasing under moderate water deficit.     

Relation between the low temperature stress and catalase activity in gladiolus somaclones (Gladiolus grandiflorus Hort.)

In order to evaluate low temperature tolerance of five variable somaclones as well as the cv. Peter Pears of gladiolus (Gladiolus grandiflorus Hort.) from which they were originated, catalase (CAT) activity and hydrogen peroxide (H₂O₂) level were measured. Before carrying out the analyses, vitroplants of these clones were exposed, during 21 days, to 8 °C temperature. In response to the stress generated by this low temperature, catalase (CAT) activity revealed on native gel and quantified by spectrophotometry, showed variable levels, being all of them higher compared to cultivar control. For these clones, strong CAT activities were always accompanied by low H₂O₂ levels. Thus, at low temperatures the antioxidants system of adapted clones is more active compared to control.