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  • Author: Dorota Szopińska x
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Abstract

The decrease of seed quality during storage is strongly associated with damage caused by free radicals. Some compounds of natural origin, known due to their antioxidative and antifungal properties, may be potentially used in organic production for seed treatment as an alternative to pesticides. The aim of the experiment was to study an ability of hydrogen peroxide and organic acid to improve germination, vigour and health of non-deteriorated and deteriorated zinnia seeds. Two seed samples, cv. Illumination and Orys, varying in initial infestation with fungi were tested. For deterioration seeds were kept at 30°C and 80% RH for 30 days. Seed quality tests were performed before and after deterioration for controls and seeds soaked in 3.0% hydrogen peroxide solution and in 1.0 and 5.0% solutions of ascorbic and lactic acids for 10, 30 and 60 min. The controls were untreated seeds, seeds soaked in 0.2% solution of Kaptan zawiesinowy 50 WP for 30 min and seeds soaked in distilled water for 10, 30 and 60 min. Treating zinnia seeds with organic acids more significantly affected seed germination and health after deterioration than before, and improvement of germination capacity was usually correlated with decrease of the percentage of abnormal diseased seedlings. Deterioration had no influence on mean germination time, whereas in particular cases treating seeds with hydrogen peroxide and organic acids negatively affected this parameter. After deterioration regardless of treatment increased number of seeds free from fungi. Lactic acid followed by hydrogen peroxide and ascorbic acid effectively limited growth of A. alternata, A. zinnia and Fusarium spp. on zinnia seeds, however at higher concentration negatively affected seed germination and vigour. Moreover, treating seeds with hydrogen peroxide and organic acids many a time increased seeds infestation with B. cinerea.

ABSTRACT

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 (H2O2) 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% H2O2 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 H2O2, 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% H2O2 solutions for 60 and 20 min, respectively. Higher concentrations of H2O2 (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.

Abstract

Priming is one of the most common methods of improving seed quality. The aim of this experiment was to study the effects of hydro- and osmopriming on the germination, vigour and hydrolytic enzymes (α-amylase, β-glucosidase, exopeptidase and lipases) activity of zinnia (Zinnia elegans Jacq.) seeds. Seeds of three cultivars: Jowita, Kirke and Orys, and Z. elegans fl.pl., a mixture of cultivars (Mix), were tested. The seeds were hydroprimed in a restricted volume of water (200 μl H2O g−1 seed, 24 h at 15°C) and osmoprimed in a polyethylene glycol solution (−1.0 MPa PEG 8000, 5 days at 20°C). Untreated seeds served as the control. The cultivars differed significantly in terms of seed quality as well as response to priming. On average, ‘Jowita’ seeds were characterised by the highest quality, expressed by the total number of germinating seeds (Gmax) and germination at the 1st and 2nd counts. Mix seeds showed the lowest quality, expressed by germination at the 1st and 2nd counts and vigour. Generally, an increase in α-amylase activity and a decrease in lipase activity was found in hydroprimed and osmoprimed seeds, and α-amylase activity was significantly higher in ‘Jowita’ seeds than Mix seeds. The applied treatments did not affect β-glucosidase and exopeptidase activity in the tested seeds. Osmopriming accelerated seed germination and influenced α-amylase and lipase activity to a greater extent than hydropriming. Among the assayed enzymes, only the activity of α-amylase may be potentially useful for the seed industry as a physiological marker of zinnia seed vigour and the effectiveness of osmopriming.

Summary

Introduction: Infestation with fungi may significantly affect the quality of seeds. However, there is no standard method for caraway (Carum carvi L.) seed health testing.

Objective: The aim of the present study was to determine the most efficient method of the detection of fungi associatyed with caraway seeds.

Methods: Seven incubation methods for evaluation of health of these seeds were compared: deep freeze blotter test, blotter test with mannitol, blotter test with polyethylene glycol, agar tests on potato-dextrose-agar (PDA) and on reduced PDA (RPDA) without seed disinfection, and agar tests on PDA and RPDA after seed disinfection. The evaluation was performed after 10 and 14 days of incubation.

Results: Thirty two fungal genera were associated with the seeds. Alternaria alternata, Cladosporium spp. and Rhizopus nigricans were identified most frequently. Prolongation of incubation time favoured growth of Fusarium spp. and R. nigricans to the highest extent.

Conclusions: The greatest seed infestation with fungi, especially Alternaria spp., was observed in the deep freeze blotter test followed by the blotter test with mannitol. Both of them could be recommended for further study on caraway seed health testing.

Abstract

The aim of the study was to determine the effect of Aloe vera (L.) Burm.f. (Aloe) and Morinda citrifolia L. (Indian mulberry) plant extracts and disinfectant Huva-San TR 50 (hydrogen peroxide stabilized with silver ions) on carrot seed quality. The seeds of two carrot cultivars Amsterdam (sample I) and Berlikumer 2 (sample II), were soaked in solutions of Aloe and Indian mulberry extracts and Huva-San TR 50 at concentrations of 0.025 %, 0.05 % and 0.1 % for 30 min. Untreated seeds and seeds soaked in distilled water for 30 min were used as controls. Seed germination was assessed after 7 and 14 days of incubation. The speed and uniformity of seed germination (vigour) were evaluated. Mycological analysis was performed using a deep-freeze blotter test. Sample I was characterized by lower germination at the first and the final counts than sample II and higher seed infestation with Alternaria radicina. Treating seeds of sample I with Morinda citrifolia plant extract at concentrations of 0.025 and 0.05 % reduced their infestation with Alternaria alternata and A. radicina, increased germination at the first and the final counts, and did not affect seed vigour. The effects of Aloe extract and disinfectant Huva-San TR 50 on seed quality parameters varied depending on their concentration. Hence, further studies are necessary to establish the optimal conditions for carrot seed treatment.

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.

Summary

Introduction: Milk thistle (Silybum marianum (L.) Gaertn.) is a medicinal plant belonging to Asteraceae family. Extract from milk thistle achenes (termed in practice as seeds) contains sylimarin, which protects liver cells against inorganic and organic toxic compounds. Objective: The aim of the research was to evaluate the effect of colour grading on the quality of milk thistle seeds. Methods: Seeds were graded manually by colour according to the Royal Horticultural Society Colour Chart, issued in Great Britain. In three samples two fractions of seeds were separated: beige and brown, whereas seeds of the fourth sample were graded into three fractions: yellow, beige and brown. The 1000-seed weight and germination of graded and non-graded seeds were evaluated. Infestation of graded seeds with fungi was assessed. Results: Brown seeds had a higher 1000-seed weight than beige or yellow ones. Germination at the final count of beige seeds did not differ as compared to that of brown seeds or was even better. Milk thistle seeds were infested with numerous fungi, however Alternaria alternata and Ulocladium consortiale predominated. Conclusions: Less mature beige seeds can be used as sowing material because their germination at the final count did not differ as compared to that of fully mature brown seeds or was even better. Infestation of these seeds with some of the fungi was lower than brown seeds.

ABSTRACT

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.

Abstract

The aim of the study was to determine the effect of electromagnetic fields and their shielding on carrot seed quality. Three sectors were separated on the device emitting electromagnetic fields: “E” - sector emitting electromagnetic radiation with the predominance of the electrical component, “EM” - sector emitting electromagnetic radiation without domination of its components and “M” - sector with a predominance of magnetic component. Fields generated by the device were also shielded with ADR TEX screen, based on a nanocomposite in which the electric component of the electromagnetic radiation is absorbed by water dispersed in a dielectric matrix in various ways. The composites exhibit high dielectric absorption and shield electric fields within the frequency range from ~100 mHz to ~100 kHz. Seed germination and vigour were evaluated at 20 °C in darkness. Mycological analysis was performed using a deep-freeze blotter test. Exposure of seeds to radiation with the predominance of the electrical component and electromagnetic radiation without domination of its components combined with shielding of electromagnetic fields with ADR TEX (E+ADR TEX and EM+ADR TEX) increased seed germination energy and germination capacity compared to these treatments without shielding and control. The percentage of abnormal diseased seedlings in treatments with shielding of electromagnetic fields with ADR TEX (E+ADR TEX, EM+ADR TEX and M+ADR TEX) was significantly lower than in the treatments without shielding and in control. None of the treatments affected seed vigour. Generally, exposure of seeds to electromagnetic radiation did not influence the incidence of fungi.

Abstract

The aim of the study was to determine the effect of electromagnetic fields and their shielding on the growth of dwarf runner bean Phaseolus coccineus L. Three sectors were separated on the device emitting electromagnetic fields: “E” - sector emitting electromagnetic radiation with the predominance of the electrical component, “EM” - sector emitting electromagnetic radiation without domination of its components and “M” - sector with a predominance of magnetic component. Fields generated by the device were also shielded with ADR TEX, a screen based on a nanocomposite in which the electric component of the electromagnetic radiation is absorbed by water dispersed within a dielectric matrix in various ways. The composites exhibit high dielectric absorption and shield electric fields within the frequency range from ~100 mHz to ~100 kHz. Electromagnetic fields with the predominance of the electrical component and without domination of its components delayed the initial emergence of runner bean seedlings. Shielding of electromagnetic field without domination of its components with ADR TEX screen protected against this negative impact on the emergence rate of young runner bean seedlings. Exposure of plants to differentiated electromagnetic fields adversely affected their growth. Plants exposed to electromagnetic radiation without domination of its components had the lowest height and the shortest internodes. Shielding of electromagnetic fields with ADR TEX screen efficiently protected against their negative impact on the plant growth. Electromagnetic fields and their shielding did not influence the size of leaves and the index leaf greenness (SPAD).