A b s t r a c tPhytosociological data were collected in 1994-1996 in plots (relevés) at the Research Station for Organic Farming and Conservation Breeding of the Polish Academy of Sciences in Popielno included in a large-area experiment conducted according to the concept and method proposed by Prof. S. Nawrocki. In a four-field crop rotation (root crops -spring barley undersown with red clover and grasses -red clover/grass mixturewinter triticale), each field was divided into two management units, organic and integrated. Data were collected in relevés by the Braun-Blanquet method, each year at the peak of the growing season. Weed abundance (% cover) in cultivated fields and the number of weed species (species richness) in crops were determined, which provided a basis for calculating the Shannon--Wiener indices of species diversity and evenness, and the Rényi profiles. The qualitative (species) and quantitative structure of weed communities was compared using the Sørensen index.A total of 115 weed taxa (species, subspecies and varieties) were identified in the examined agro-phytocenoses. Echinochloa crus-galli, Chenopodium album, Matricaria maritima subsp. inodora, Capsella bursa-pastoris, Thlaspi arvense and Stellaria media were the most abundant. Weed infestation was slightly higher in the organic farming system than in the integrated system. Organic farming contributed to higher weed species diversity in root crops, red clover/grass mixtures and winter triticale. Weed species richness was reduced in red clover/grass stands, while root crops and -to a lesser degree -spring barley undersown with red clover and grasses decreased weed species diversity. The species composition and in particular the quantitative structure of weeds were affected by crop species and cultivation regime rather than by the farming system. Weed communities of crops grown under organic and integrated farming systems were more similar with regard to species composition than the quantitative structure.

The mechanism preferentially regulating accumulation of raffinose family oligosaccharides (RFOs) or galactosyl cyclitols in legume seeds still remains unknown. The broad range of raffinose family oligosaccharides and galactosyl pinitols in the composition of seeds of Vicia genus gives researchers an exceptional opportunity for investigations on relationships in biosynthesis of both types of a-D-galactosides. Feeding explants of Vicia species radically different in the composition of RFOs and galactosyl pinitols with basic galactose acceptors, sucrose (for RFOs) or cyclitols (for galactosyl cyclitols) can be a helpful method for assessment of their regulatory role in accumulation of a-D-galactosides in seeds. Garden vetch (Vicia sativa L.) seeds, naturally accumulating RFOs, demonstrated an ability to take up and use exogenously applied D-pinitol and D-chiro-inositol for synthesis of their mono-, di-and tri-galactosides. Together with the accumulation of new galactosides, the concentration of RFOs decreased. In fine-leaved (Vicia tenuifolia Roth.) vetch seeds such a remarkably high concentration of galactosyl pinitols (GPs) was discovered that they nearly replaced RFOs, which is unique among legumes. If the accumulation of both types of galactosides is correlated with concentration of galactose acceptors, elevated levels of sucrose or myo-inositol should promote accumulation of RFOs, instead of GPs. Unexpectedly, feeding fine-leaved vetch raceme explants with myo-inositol or sucrose promoted accumulation of GPs, but not of RFOs. Our comparison of accumulation and biosynthesis of both types of galactosides (RFOs and GPs) throughout development and maturation of seeds from fine-leaved vetch has indicated that preferential accumulation of GPs is associated with the drying of seeds during maturation. Different patterns in activities of enzymes engaged in RFOs' biosynthetic pathway and galactosyltransferases involved in biosynthesis of GPs indicated that distinct forms of enzymes can operate in both pathways. The feeding of explants with D-chiro-inositol causes accumulation of fagopyritols B1 in seeds of both Vicia species, which suggests presence of the same or a similar form of galactinol synthase. Accumulation of fagopyritols in fine-leaved vetch seeds did not affect accumulation of RFOs or galactosyl pinitols.Keywords D-Pinitol Á D-chiro-Inositol Á Raffinose oligosaccharides Á Galactosyl cyclitols Á Seed Á Vetch Abbreviations RFOsRaffinose family oligosaccharides GPs a-D-Galactosides of D-pinitol Communicated by F. Corbineau.

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