Aims -Iran is one of the main centres of diversity for the genus Onobrychis Miller. This study includes 55 specimens from eleven representative wild populations of Onobrychis carduchorum C.C.Towns. originating from their natural habitats in Iran. The aims of this study are to provide a detailed taxonomical, morphological, genetic and ecogeographical characterization of O. carduchorum in Iran. Methods -The specimens which represent all Iranian populations were biometrically assessed using 45 quantitative and fifteen qualitative morphological characters. The phenotypic variation among the populations depends on various environmental factors; thus at each sample site we recorded data regarding longitude, latitude, altitude, slope inclination, slope orientation, substrate, minimum and maximum annual temperatures, number of rainy days, annual precipitation as well as soil traits including texture, electrical conductivity, organic carbon, total nitrogen, available phosphorus, available potassium, total neutralizing value, pH, and saturation percentage. The floristic composition of each population habitat was examined as an indicator of environmental conditions. To assess genetic variation, we obtained nucleotide sequence data from the internal transcribed spacer of the nuclear ribosomal DNA (ITS) and carried out genomic fingerprints using inter-simple sequence repeat (ISSR) analysis. Results -Cluster analysis of morphological characters showed that the eleven populations could be divided into two major groups including five subgroups. Principal component analysis (PCA) of floristic data confirmed the two major morphological groups suggesting habitudinal segregation among the groups and the indicative value of floristic composition of study sites in assessing intraspecific variation in the target species. Furthermore, canonical correspondence analysis (CCA) of ecogeographic data showed correlations between morphological variations and ecogeographic factors. Longitude, latitude, substrate, available potassium, clay%, total nitrogen, organic carbon, slope orientation, sand%, texture, altitude and rainy days are apparently the main environmental variables associated with morphological groups of O. carduchorum. Both ITS and ISSR data indicate that O. carduchorum is a young species with a recent divergence of its populations.
Drought stress was evaluated with polyethylene glycol 6000 (PEG 6000) treatment in Dunaliella salina, a microalga known for its great ability to withstand salinities of more than 30%. The aim was to explore the acclimation mechanisms used by the microalga to regulate its growth and physiology during coping with drought stress. The microalga was subjected to culture mediums containing 2 and 5% PEG for 25 days and was compared with a control culture medium. Significant decrease in growth parameters such as specific growth rate, biomass and number of divisions per day was demonstrated in PEG-treated algae. During PEG treatment, chlorophylls slightly increased, while β-carotene and total protein were not affected. Osmolytes, as well as carbohydrates, were found to be significantly higher in PEG-treated algae than in control. Increased catalase and ascorbate peroxidase activities were proportionally related to PEG concentrations in the cultures. The PEG-treated cells accumulated a considerable amount of hydrogen peroxide and malondialdehyde, especially at higher PEG concentrations. Electrolyte leakage increased, regardless of the PEG concentrations applied, while DNA fragmentation was not observed after 25 days of treating with PEG. It was concluded that Dunaliella cells could respond to the drought stress, probably by using a higher accumulation of a range of osmolytes and also more stimulation of the antioxidant enzymatic system.
In this study 40 specimens from 8 representative Iranian populations of Onobrychis viciifolia SCOP. were collected from their natural habitats. The specimens were biometrically assessed using 43 quantitative and 15 qualitative morphological characters. At each sample site we recorded ecogeographical variables. In order to evaluate the difference between the variation due to phenotypic responses and genetic adaptation, we generated nucleotide sequence data from the internal transcribed spacer of the nuclear rDNA genes (ITS) and carried out genomic fingerprints using inter‐simple sequence repeat PCR (ISSR). Cluster analysis of morphological characters divided the eight populations into three major groups. Leaf length, leaflet length and width, calyx length, plant height, and stem length were introduced as diagnostic characters for three different morphological groups. Furthermore, canonical correspondence analysis (CCA) of ecogeographical data showed correlations between morphological variations and ecogeographical factors. Clay%, saturation percentage (SP), total neutralizing value (TNV%), texture, minimum temperature, and geographic separation were the main environmental variables associated with morphological groups of O. viciifolia. ISSR analysis revealed three main groups which are in correspondence with morphological groups, indicating that the three morphological groups have been shaped by genetic and phenotypic responses to environmental conditions. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
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