Miscanthus ×giganteus Greef et Deu. (Poaceae), a hybrid of Miscanthus sinensis and M. sacchariflorus native to Japan, is an ornamental and a highly lignocellulosic bioenergy crop, cultivated in the European Union as an alternative source of energy. This grass reproduces exclusively vegetatively, by rhizomes or via expensive in vitro micropropagation. The present study was aimed at finding the barriers that prevent sexual seed production, based on detailed embryological analyses of the whole generative cycle, including microsporogenesis, pollen viability, megasporogenesis, female gametophyte development, and embryo and endosperm formation. Sterility of M. ×giganteus results from abnormal development of both male and female gametophytes. Disturbed microsporogenesis (laggard chromosomes, univalents, micronuclei) was further highlighted by low pollen staining. The frequency of stainable pollen ranged from 13.9% to 55.3% depending on the pollen staining test, and no pollen germination was observed either in vitro or in planta. The wide range of pollen sizes (25.5-47.6 μm) clearly indicated unbalanced pollen grain cytology, which evidently affected pollen germination. Only 9.7% of the ovules developed normally. No zygotes nor embryos were found in any analyzed ovules. Sexual reproduction of M. ×giganteus is severely hampered by its allotriploid (2n=3x=57) nature. Hybrid sterility, a strong postzygotic barrier, prevents sexual reproduction and, therefore, seed formation in this taxon.

The research and analysis of the bactericidal properties of the spacer knitted fabric with the UV-C system are presented in this paper. The disintegration factor affecting the bacteria in the knitted fabric is the UV-C radiation in the range of 265–270 nm distributed via woven optical fibres. The way of integrating elements of the system generating the UV-C radiation in the structure of the spacer knitted fabric was designed, as well as various configurations of optical fibres arrangement, fibre density, number of radiation sources, and diode types were tested. The material was contaminated with selected microorganisms indicative of sanitary contamination and important in terms of nosocomial infections. The scope of the research included microbiological (quantitative and qualitative) analyses of selected taxonomic groups of microorganisms (mesophilic bacteria, fungi, actinomycetes) before and after the irradiation process. The analysis of the research results and the applied modification of the knitted fabric turned out to be effective in reducing the amount of potentially pathogenic microorganisms.

Ongoing energy measurement is one of the parameters such as: electron beam current, transporter speed, or scanning width, that must be recorded according to the conditions imposed in the accelerator validation procedure. Described measurement method based on the use of a secondary electron collecting electrode has been tested at the electron beam linear accelerator installation typically used for radiation sterilization. Data processing and presentation of the electron beam characteristics is based on the information obtained via dedicated pulse acquisition interface. The energy spectra parameters provide data for modeling and calculation of dose distribution for irradiation process optimization and also knowledge of accelerator RF alignment in case of service.

Using doubled haploid technologies inbreeding can significantly reduce the time to obtain homozygous parental lines required for the production of F1-hybrid of vegetable crops. This study aims to investigate the influence of factors on the efficiency of carrot embryogenesis in isolated microspore culture to optimise the elements of protocol for producing doubled haploids. Microspores were isolated from inflorescences of 21 genotypes and incubated in NLN13 medium supplemented with 0.1 mg·dm ^–3 2,4-dichlorophenoxyacetic acids, 0.1 mg·dm ^–3 1-naphthyl acetic acids, 130 g·dm ^–3 sucrose, and 400 mg·dm ^–3 casein hydrolysate and its modifications. Embryoids and their groups were formed after 2–6 months, in some cases after 12 months of cultivation. Depending on the variant, the embryogenesis efficiency averaged from 0 to 4.9 embryoids or groups of embryoids per Petri dish (10 cm ³). Embryoids within the group were formed from different microspores. No significant effects of inflorescence position on the plant (branching order), sucrose, and casein hydrolysate concentration in the medium were observed. Significant advantages (p ≥ 0.05) for some genotypes were shown: 1) microspore suspension density 4·104 cells·cm ^–3 (5.0 embryoids per Petri dish were formed at a microspore suspension density of 4·104 cells·cm ^–3, 0.0 embryoids per Petri dish at a density of 8·104 cells·cm ^–3); 2) cultivating microspores of tetrad and early mononuclear stage (4.9 ±3.1 embryoids per Petri dish were obtained by culturing tetrads and early mononuclear microspores, while 0.6 ±0.7 embryoids per Petri dish were obtained by culturing of later developmental stages); 3) high-temperature treatment duration of five days (4.9 ±2.1 embryoids per Petri dish were obtained after five days of high-temperature treatment, 2.7 ±2.6 embryoids per Petri dish formed after two days of high-temperature treatment; 9.8 ±4.7, 10.1 ±6.1, 0.0 ±0.0 embryoids per Petri dish formed after two, five and eight days of high-temperature treatment respectively); 4) adding colchicine 0.5 mg·dm ^–3 to the nutrient medium for two days of high-temperature treatment, followed by medium replacement (3.3 ±2.6 embryoids per Petri dish were obtained by using a nutrient medium with colchicine, while 1.7 ±1.5 embryoids per Petri dish were obtained by culturing in the reference variant).