Botanica Lithuanica, Volume 10, Number 2

2004 m.

The main aim of this study was to quantify morphological variations of M. struthiopteris and to investigate how different plant organs were correlated. More than 9000 plants (rootstocks) from different parts of Norway were studied. Fertile fronds (sporophylls) had developed in 14.6 % of the investigated rootstocks. A maximum of 9 sporophylls and 20 sterile fronds (trophophylls) were found on one rootstock. Intermediate fronds (partly fertile and sterile) were found on 13.6 % of the fertile plants. The plants had to reach a certain size (age) before they started to produce sporophyll, and this threshold was generally associated with more than 6 trophophylls, a trophophyll taller than 120 cm, and a rhizome thickness exceeding 6 cm. A major part of the plant‘s biomass was constituted by remaining leaf scars (trophopods) and based on their numbers; the biggest rootstock investigated was estimated to be at least 70 years.

Keywords: sporophyll, trophophyll, trophopod, rootstock, biomass.

A taxonomic study of Emilia Cass. in Nigeria was conducted in search of useful and stable anatomical characters for the identification of the species. Stomatal type and index indicates that Emilia praetermissa is a hybrid between E. coccinea and E. sonchifolia. Larger cell size in all studied size attributes supports E. praetermissa as an allotetraploid. Trichome type, stomata type, stomata shape and size attributes are all characters of E. sonchifolia and E. praetermissa that were consistently close in resemblance and values to suggest E. sonchifolia as the closer parent of E. praetermissa exerting gene dominance. This would also suggest introgression between E. sonchifolia and E. praetermissa.

Keywords: anatomical characters, stomatal type, allotetraploid, trichome, gene dominance.

Effects of fertilisers Expert GardenerTM for acidophilous plants (33-11-11+ microelements) and Peat PG-Mix (14-16-18+ microelements) on the growth of Vaccinium angustifolium seedlings were tested. It appeared that both fertilisers are suitable for Vaccinium angustifolium and their average effect on the shoot height and branching of seedlings is approximately the same, but in case of Expert GardenerTM the proportion of seedlings with a higher number of shoots is larger. It is enough to fertilise seedlings twice during the first growing period, using 1 g of fertiliser per 1 litre of water. More frequent application of fertilisers in Estonian climatic conditions does not stop the seedlings growth before frosts and, therefore, plants may be damaged.

Keywords: Vaccinium, lowbush blueberry, seeds, germination, propagation.

The paper presents notes on the occurrence of straminipilous fungi belonging to the Achlya and Newbya genera in various freshwater basins of Lithuania. Short descriptions, distribution patterns, and illustrations of 16 species are provided; their morphological characters and taxonomy are discussed. Achlya americana, A. bisexualis, A. colorata, A. conspicua, A. diffusa, A. dubia, A. flagellata, A. orion, A. prolifera, A. radiosa, Newbya apiculata, and N. polyandra are reported for the first time in Lithuania.

Keywords: straminipilous fungi, Achlya, Newbya, species diversity, Lithuania.

In 1999–2002 investigations on mycological state of fruit, berries, vegetables, and other plant-origin food products grown in Lithuania and imported from 24 countries were performed; most frequent micromycete species were determined. The ability of 403 micromycete strains to excrete secondary metabolites was tested. Effect of 66 strains (identified as active producers of secondary metabolites) upon the BALB/c mice was investigated. It was revealed that about 10 ? of investigated micromycete strains produce toxic metabolites that pose a potential health hazard for people consuming or handling the foodstuff.

Keywords: berries, fruit, vegetables, micromycetes, toxic metabolites, mice.