Effects of Lactone- and Ketone-Brassinosteroids of the 28-Homobrassinolide Series on Barley Plants under Water Deficit.

The aim of this work was to study the ability of 28-homobrassinolide (HBL) and 28-homocastasterone (HCS) to increase the resistance of barley (Hordeum vulgare L.) plants to drought and to alter their endogenous brassinosteroid status. Germinated barley seeds were treated with 0.1 nM HBL or HCS solutions for two hours. A water deficit was created by stopping the watering of 7-day-old plants for the next two weeks. Plants responded to drought through growth inhibition, impaired water status, increased lipid peroxidation, differential effects on antioxidant enzymes, intense proline accumulation, altered expression of genes involved in metabolism, and decreased endogenous contents of hormones (28-homobrassinolide, B-ketones, and B-lactones). Pretreatment of plants with HBL reduced the inhibitory effect of drought on fresh and dry biomass accumulation and relative water content, whereas HCS partially reversed the negative effect of drought on fresh biomass accumulation, reduced the intensity of lipid peroxidation, and increased the osmotic potential. Compared with drought stress alone, pretreatment of plants with HCS or HBL followed by drought increased superoxide dismutase activity sevenfold or threefold and catalase activity (by 36%). The short-term action of HBL and HCS in subsequent drought conditions partially restored the endogenous B-ketone and B-lactone contents. Thus, the steroidal phytohormones HBL and HCS increased barley plant resistance to subsequent drought, showing some specificity of action.

HPLC and GC/MS analysis of Prunus ulmifolia Franch. (syn. Aflatunia ulmifolia (Franch.) Vassilcz.) leaves growing in South-Eastern Kazakhstan.

Prunus ulmifolia Franch. (Rosaceae) was investigated for its phytochemical composition from South-Eastern Kazakhstan for the first time. HPLC analysis confirmed rutin (0.88%) in ethanol extract, and the extract also exhibited antioxidant activity. The GC/MS analysis identified total 44 components from main groups e.g. oxygenated monoterpenes (51.06%), oxygenated sesquiterpenes (20.33%), non-terpene derivatives (18.71%), and sesquiterpene hydrocarbons (7.89%), and the maximum content was of acyclic alcoholic monoterpenoid citronellol (36.58%). The hierarchical cluster analysis (HCA) from previous reports and present study was used to demonstrate the variations between essential oil compositions in different Prunus species. It formed three main clusters, cluster I consisted of species with benzaldehyde as dominant component. Cluster II included plants with benzaldehyde as secondary component, and cluster III was of P. ulmifolia in which benzaldehyde was not detected. Further, the essential oil was assessed for cytotoxic and antimicrobial activities too, and it showed better cytotoxic but poor antimicrobial activities.

Chemical composition of the essential oil from carnation coniferous (Dianthus acicularis Fisch. ex Ledeb) growing wild in Northern Kazakhstan.

The aim of the study was to investigate volatile compounds from the aerial parts of Dianthus acicularis of the genus Dianthus of the family Caryophyllaceae grown wild in Northern Kazakhstan for the first time. D. acicularis is a typical Trans-Volga-Kazakhstani endemic. D. acicularis has high resistance to the bacterial wilt, a serious disease caused by Burkholderia caryophylli. The qualitative and quantitative compositions of the specimens of the essential oils were analysed by the method of GC-MS. The main constituents of D. acicularis essential oil were methyl ketones - 2-pentadecanone (26.9-32.2%) and 2-tridecanone (4.7-17.7%), identified for the first time in the Dianthus genus. The methyl ketone activity provides protection of the plants from herbivores and fungal pathogens. One can suppose that the presence of 2-pentadecanone and 2-tridecanone in the essential oil of carnation coniferous provides its resistance to different insects and pathogens, including the resistance to the bacterial wilt.

Chemical Composition of the Essential Oil of the Boreal Relict of Pyrola rotundifolia L. from Northern Kazakhstan.

In Kazakhstan Pyrola rotundifolia L. is the plant-relict in the flora of insular pine forests of the region of low hillocks and declivities in Kazakhstan - a group of insular pine forests of Kokshetau, Bayanaul and Karkaralinsk. In this study, the essential oils from dried aerial parts of P. rotundifolia, collected in natural habitats of the State National Natural Park "Burabay" (Akmola oblast, Northern Kazakhstan), were extracted by hydrodistillation and analyzed by gas chromatography - mass spectrometry. The yield of the essential oil amounted to 0.057 % in relation to the mass of the air-dry raw material. The major components in dried plant oil were 2,6-dimethyl-1,4-naphthoquinone (12.99-93.49%) and dibutyl phthalate (4.42-40.48%), depending on the growth conditions.