The objective of this study was to determine the concentrations of isoflavones in the cultivars and ecotypes of red clover (Trifolium pratense L.) in a whole above ground part of a plant and separately in stems, leaves and flowers at flowering stage. Isoflavones were extracted using acidified aqueous methanol and subsequent analyses of the extracts were carried out by ultra-performance liquid chromatography coupled with a photodiode array detector. Red clover accumulated the highest concentrations of formononetin (51%) and biochanin A (40%) at flowering stage.

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Only a few species of the large Astragalus genus, widely used for medicinal purposes, have been thoroughly studied for phytochemical composition. The aim of our research was to investigate the rarely studied species A. glycyphyllos L. and A. cicer L. for the distribution of mineral elements and phytochemicals in whole plants at two growth stages and in morphological fractions. We also investigated the capacity of the plant extracts to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and to chelate ferrous ions. Chemical composition and antioxidant properties depended on species, maturity, and plant part. Herbal material of A. glycyphyllos was richer in Fe, total phenolics, and flavonoids, whereas extracts of A. cicer showed a higher antioxidant activity. Young plants had more isoflavones, showed greater quenching of DPPH radicals, and exhibited better mineral profiles than flowering plants. Among plant parts, leaves were the most valuable plant material according to most characteristics investigated. Isoflavone concentration in flowers was lower than in leaves and stems. None of the Astragalus samples contained detectable amounts of the alkaloid swainsonine. The study demonstrates the potential of plant material from two Astragalus species as a valuable source of iron, phenolic substances including isoflavones, free-radical scavengers, and Fe2+ chelators for pharmaceutical use.

Approaching switchgrass (Panicum virgatum L.) as a multifunctional energy plant, it is important to comprehensively study the composition and partitioning of organic substances in the biomass. The character of carbohydrates and lignin concentration variation was assessed in switchgrass biomass cut at two maturity stages (heading and seed filling) in the first and second harvest years. Quality components partitioning in the biomass of aboveground plant parts was examined in leaves, stems and panicles of the most productive switchgrass accessions cut at seed filling. The concentrations of lignocellulose (NDF), cellulose (Cel), sum of structural carbohydrates (holocellulose -HoCel), sum of nonstructural and structural carbohydrates (ΣCH 2 O) and lignin in switchgrass biomass of both plant development stages in the second harvest year were significantly higher, whereas an average hemicellulose (HCel) concentration was significantly lower compared with the respective parameters in the first harvest year. The concentrations of nonstructural carbohydrates (NSC) and their individual fractions (water soluble carbohydrates (WSC) and starch) in biomass were similar both in the first and second harvest years. The concentrations of NDF, Cel, HoCel and ΣCH 2 O and particularly lignin at seed filling were significantly higher compared with the respective data at heading in both harvest years. High lignin concentration (105 g kg -1 dry matter (DM)) in switchgrass biomass at seed filling in the second harvest year showed its great suitability for solid biofuel production. Considerable amount of ΣCH 2 O (693-742 g kg -1 DM) indicated that switchgrass biomass at this stage fits for the second-generation bioethanol production. At heading, switchgrass in the second harvest year produced quite a high NSC yield (an average 28.4 g plant -1 ) and low lignin output (an average 19.3 g plant -1 ), which is a favourable feature of feedstock for biogas production, biomass at seed filling is less suitable for that than at heading. Switchgrass plant part significantly (P < 0.01) affected the concentration of all biomass quality attributes tested, but did not affect HCel concentration. Accessions' DM yield correlated positively with NDF (r = 0.781, P < 0.05), Cel (r = 0.882, P < 0.01) and lignin (r = 0.517) and negatively with WSC and NSC (r = −0.982, −0.959; P < 0.01).

An average dry ma�er yield structure (three cuts per growing season) in relation to agronomically valuable characteristics of six forage grass species and a year of herbage utilization was studied over the period of 1989-2002 in Lithuania. The most productive species of the first cut of two years of herbage utilization were Phleum pratense (P < 0.01) and Festulolium hybrids (P < 0.05) (average dry ma�er yield were 7.42 and 6.66 t/ha, respectively), moderately productive -Festuca pratensis, Dactylis glomerata and Lolium perenne (5.58, 5.42 and 5.20 t/ha), significantly lower (P < 0.01) yielding was Poa pratensis (4.19 t/ha). During two years of herbage utilization Dactylis glomerata produced significantly (P < 0.01) higher dry ma�er yield of a�ermath -7.30 t/ha. Other grass species were ranked in the following order: Festulolium hybrids 5.85 t/ha, Festuca pratensis 4.94 t/ha, Poa pratensis 4.57 t/ha, Lolium perenne 4.48 t/ha, and Phleum pratense 3.92 t/ha. Dactylis glomerata and Poa pratensis distinguished by the highest a�ermath percent in the structure of the annual dry ma�er yield (57.7 and 52.2%). Phleum pratense formed an especially poor a�ermath -only 34.6%. An average annual dry ma�er yield data analysis of two years of herbage utilization over the period of [1989][1990][1991][1992][1993][1994][1995][1996][1997][1998][1999][2000][2001][2002] showed that Dactylis glomerata and Festulolium hybrids were most productive (P < 0.01) species.