The high infestation rate of zinnia (Zinnia elegans Jacq.) seeds with fungi, especially pathogenic Alternaria zinniae, has frequently resulted in a poor germination capacity associated with a high number of abnormal diseased seedlings. The effect of hydrogen peroxide (H 2 O 2 ) treatment on the germination, vigour and health of zinnia seeds was investigated. Two samples of zinnia seeds -sample I, characterised with a low germination capacity (39.5%) and a high level of seed infection with A. zinniae (76%), and sample II, with a high germination capacity (87%) and free from this pathogen -were tested. For treatment, seeds were soaked in 3%, 6%, 9% and 12% H 2 O 2 solutions for 10, 20, 30 and 60 min. Initially, the controls were seeds soaked in distilled water for 10, 20, 30 and 60 min, and then the results of selected treatments were compared with results obtained for untreated seeds and seeds treated with a fungicide (20% carbendazim and 45% thiram). The fungi Alternaria spp. and Fusarium spp. were frequently identified on tested seeds. The concentration of hydrogen peroxide affected the quality of zinnia seeds to a higher extent than the treatment time. However, all of the treatments applied, regardless of time and concentration of H 2 O 2 , positively affected seed health, significantly reducing seed infestation by fungi in both samples. Moreover, the lowest level of A. zinniae infection was observed if seeds were soaked in 6% and 9% H 2 O 2 solutions for 60 and 20 min, respectively. Higher concentrations of H 2 O 2 (9% and 12%) negatively influenced seed germination and vigour, especially in sample II. These findings suggested that the treatment of zinnia seeds with hydrogen peroxide can effectively improve germination mostly in samples heavily infected with pathogens, which means that it should be preceded by seed health evaluation.

Alternaria alternata and Alternaria radicina are fungal species that occur in several food crops and may produce mycotoxins and phytotoxins. The toxigenic profile of A. alternata and A. radicina isolated from carrot and other umbelliferous plants was determined by growing the fungus on rice and carrot discs. Most of the tested isolates of A. alternata produced the mycotoxins tenuazonic acid, alternariol, alternariol methyl ether and altertoxin-I on rice. Only alternariol and alternariol methyl ether were produced on carrot discs. When cultured on rice, none of the isolates of A. alternata from umbelliferous plants produced AAL toxins and fumonisins. AAL toxins, but not fumonisins, were instead produced by A. alternata f. sp. lycopersici isolate NRRL 18822 isolated from tomato. A. radicina produced the phytotoxic compounds radicinin, epi-radicinol and radicinol on carrot discs, whereas it produced radicinin and radicinol on rice. Although A. alternata has been frequently found in organic carrots, none of the above mycotoxins was detected in carrot roots or in carrot commercial products. The reduction of alternariol and alternariol methyl ether during carrot juice processing at laboratory scale was estimated to be >98%. Based on these findings and previous reports, it can be concluded that Alternaria mycotoxins in carrots do not represent a hazard for consumers.

Milk thistle (Silybum marianum (L.) Gaertn.) is one of the most important medicinal plants. The fungi infesting its seeds may negatively influence their germination and health-promoting properties. However, there is no standard method for S. marianum seed health testing. The aim of this study was to find a suitable method for the detection and identification of fungi in/on milk thistle seeds. The following tests were used: deep-freeze blotter test, blotter test with an addition of mannitol, blotter test with an addition of polyethylene glycol, agar test on potato-dextrose agar (PDA), agar test on PDA after seed disinfection, agar test on reduced PDA and an agar test on reduced PDA after seed disinfection. Seeds were incubated for 10 and 14 days. The most prevalent fungi were: Alternaria alternata, Botrytis cinerea, Cladosporium spp., Fusarium spp., Penicillium spp., Rhizopus nigricans and Verticillium spp. A deep-freeze blotter test followed by a blotter test with an addition of mannitol and a blotter test with an addition of polyethylene glycol performed for 14 days could be recommended for the further study of milk thistle seed health testing, as they favoured the growth of the most important fungi.

Seed infection with Alternaria spp. is an important source of severe carrot diseases. The aim of the study was to evaluate the effects of carrot seed treatments with acetic acid, grapefruit extract and volatile compounds of fir (Abies alba Mill.) and thyme (Thymus vulgaris L.) essential oils on their germination, vigour and health. Seeds of two samples were soaked for 30 min in 0.5, 1 and 2% acetic acid, 0.5 and 1% Biosept Active (33% of grapefruit extract), or treated for 72 h or 96 h with volatile compounds of fir and thyme oils individually (10 µl), and jointly (5+5 µl). Controls were untreated seeds and seeds soaked in distilled water. Acetic acid effectively controlled A. alternata and A. radicina in both samples, and did not affect adversely seed germination, however, at the highest concentration deteriorated seed vigour. Biosept Active was less effective, however at 1% concentration decreased seeds infestation with A. alternata in sample I, and at concentrations of 0.5 and 1% reduced percentages of seeds infested with A. alternata and A. radicina in sample II. Essential oils treatments in some cases favoured growth of A. dauci and A. radicina.

Summary Introduction: : Milk thistle (Silybum marianum (L.) Gaertn.) is an important medicinal plant. Achenes of milk thistle contain sylimarin, protecting liver cells against toxic compounds. Objective: The aim of the research was to find an optimum method of evaluation of milk thistle seed germination. Methods: Ten seed samples were tested. The seeds were germinated: on top of blotter paper, on top of blotter paper after seed disinfection, between pleated blotter paper, in rolled blotter paper and in sand. Germination at the first and final counts, the percentages of abnormal seedlings and dead seeds were determined. The correlation coefficients between seed germination, evaluated with various methods, and seedling emergence were calculated. Moreover, fungi associated with seeds and diseased seedlings were identified. Results: The lowest percentage of normal seedlings was observed after germination on the top of blotter. Highly significant positive correlations were noted between seedling emergence and seed germination at the final count evaluated in rolled paper, between pleated paper and in sand. The fungi from genera: Alternaria, Fusarium, Penicillium, Trichoderma, Ulocladium and Verticillium were frequently identified on seeds and seedlings. Conclusions: Infestation with fungi significantly affected milk thistle seed germination and plant emergence. Germination in rolled blotter paper may be recommended for evaluation of milk thistle seed germination, as the most practical and significantly correlated with seedling emergence.