Marcin Domaciuk

Differences in the fruit structure and the location and content of bioactive substances in Viburnum opulus and Viburnum lantana fruits

Many Viburnum species are popular ornamental shrubs and, simultaneously, highly valued medicinal plants as a source of many bioactive compounds, including antioxidants. Viburnum bark, flowers, and fruits are widely used in traditional and folk medicine, and the fruits of some species are used as cooking ingredients. The knowledge of the microstructure of Viburnum fruits and the accumulation sites of bioactive substances in these organs is rather poor. Comparative analyses of the microstructure of ripe Viburnum opulus and Viburnum lantana drupes were carried out using light, scanning, and transmission electron microscopes. The location of various groups of metabolites in the fruits of both species was determined with the use of histochemical tests and fluorescence microscopy. Additionally, the major antioxidants, i.e. carotenoids, polyphenols, and flavonoids, were quantified and a number of morphometric traits of the drupes were presented. The V. opulus and V. lantana fruits were found to differ in some morphological traits and in many characteristics of the pericarp anatomy and ultrastructure. It was shown that the Viburnum fruits contained lipids and lipid compounds (carotenoids, essential oils, steroids, and saponins), polyphenols (tannins, flavonoids, and anthocyanins), pectins, and proteins. The fruits of V. opulus contained greater quantities of carotenoids, polyphenols, flavonoids, steroids, and pectins than the V. lantana drupes, whereas the latter were characterised by higher contents of essential oils, saponins, and proteins. The metabolites were located in different pericarp layers, but the greatest amounts were identified in the drupe skin.

Specific ultrastructure of the leaf mesophyll cells of Deschampsia antarctica Desv. (Poaceae)

The ultrastucture of mesophyll cells of Deschampsia antarctica Desv. (Poaceae) leaves was investigated using the standard method of preparing material for examination in transmission electron microscopy (TEM). The investigated leaves were collected from the Antarctic hairgrass growing in a tundra microhabitat and representing xermorphic morphological and anatomical features. The general anatomical features of mesophyll cells are similar to those in cells of another grass leaves. The observations of the ultrastructure of mesophyll cells have shown that the organelles are located close to each other in a relatively small amount of the cytoplasm or closely adhere to each other. Organelles such as mitochondria, peroxisomes, and Golgi apparatus, as well as osmiophilic materials are gathered close to the chloroplasts. The chloroplast of the mesophyll cells of the D. antarctica leaf can form concavities filled with the cytoplasm. Such behaviour and ultrastructure of organelles facilitate exchange/flow of different substances engaged in the metabolic activity of the cell between cooperating organelles.

Optimization of in vitro culture conditions influencing the initiation of raspberry (Rubus idaeus L. cv. Nawojka) cell suspension culture

The purpose of our investigation was to determine appropriate conditions for induction of raspberry (Rubus idaeus cv. Nawojka) cell suspension culture. The established callus culture obtained from leaf explants was used as an inoculum for cell culture initiation. Five combinations of plant growth regulators: 1) 4.0 mg l-1 IAA and 1.0 mg l-1 BAP; 2) 0.25 mg l-1 2,4-D; 3) 0.5 mg l-1 2,4-D; 4) 2.0 mg l-1 NAA and 2.0 mg l-1 BAP; 5) 4.0 mg l-1 NAA and 2.0 mg l-1 BAP, added into modified Murashige and Skoog (1962) medium, were tested in order to get the callus culture suitable for initiation of a cell suspension. The best callus (vigorously growing, healthy and friable) was obtained on the medium supplemented with 4.0 mg l-1 IAA and 1.0 mg l-1 BAP. To find the appropriate culture conditions for dispersing callus tissue in liquid medium into single cells and small aggregates, four combinations of plant hormones (auxins and cytokinins) were tested. The best culture medium for induction of raspberry cv. Nawojka cell suspension appeared to be the one supplemented with 1.0 mg l-1 2,4-D. Also the medium with 8.0 mg l-1 IAA and 1.0 mg l-1 BAP was similarly efficient.