Background: Damask roses (Rosa damascena Mill.) are mainly used for essential oil production. Previous studies have indicated that all production material in Bulgaria and Turkey consists of only one genotype. Nine polymorphic microsatellite markers were used to analyze the genetic diversity of 40 accessions of R. damascena collected across major and minor rose oil production areas in Iran.

No abstract

The hypothesis that the extracellular concentration of sugars helps regulate the acclimation of plant cells to cold was tested in this work. Suspension cultures were used to control the concentration of sugars in the medium supplied to barley cell cultures (Hordeum vulgare L. cv. Igri), replacing the medium daily to help maintain the concentration. Freezing tolerance and the levels of mRNA expression of the stress-response genes blt4.9 (coding for a non- specific lipid transfer protein) and dhn1 (coding for a dehydrin) were measured. Similar levels of freezing-tolerance and gene expression were obtained in the experiments as occur during cold-acclimation in the crown of the whole plant. In the cell cultures, cold (6/2 degrees C) did not induce an increase in freezing tolerance or in the expression of detectable levels of blt4.9 or dhn1 mRNAs when only 1 g l-1 sucrose was supplied. However, the cells in this low sucrose medium in the cold were not sugar-starved, indicating that this did not explain the failure of the cells to acclimate when grown in the cold environment. Ten g l-1 sucrose supplied to cells grown in the warm (25 degrees C) induced acclimation to freezing and up-regulation of expression of blt4.9 and dhn1 mRNAs. Osmolality of the medium did not explain this. Thirty g l-1 sucrose induced yet higher levels of freezing tolerance and of blt4.9 and dhn1 mRNAs in cultures grown in either the cold or the warm environment. The results implicate sugars in the regulation of cold acclimation

Agropyron desertorum and Lophopyrum elongatum were grown in a control environment or acclimated in high-salt (daily exposure to 75 or 150 mm NaCl for 6 d), cold (6/2°C for 14 d) or drought environments (watering withheld for 6 d). Lophopyrum elongatum was constitutively tolerant to salt and also acclimated more to salt than did A. desertorum whereas A. desertorum acclimated more to cold and drought. Dehydrin and non-specific lipid transfer protein (nsLTP) mRNA sequences and polypeptides increased more, during acclimation to cold and drought, in A. desertorum than in L. elongatum crowns. Expression of immunologically identified dehydrin polypeptides was much higher in drought-acclimated A. desertorum than in any other species/treatment combination. The most strongly expressed were 42 and 20 kDa. No change in dehydrin or nsLTP polypeptides were detected in the crowns during acclimation to salt. Overall, there was stronger acclimation to dehydrative stresses, at the molecular level, in A. desertorum than in L. elongatum crowns. Differences in dehydrin and nsLTP mRNA and polypeptide expression during acclimation to different stresses indicated that plants sense the differences between different primary potential causes of cellular dehydration.

No abstract