Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 35

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  Bipolaris sorokiniana
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Bipolaris sorokiniana is a dangerous pathogen of plants from Poaceae family. A secondary metabolite with carcinogenic properties produced by this fungus is sterigmatocystin. A field experiment with inoculation of the grain of 9 spring barley genotypes with B. sorokiniana No. 36 was carried out in the years 2012–2014 in the Zamość region. Field observations revealed leaf spot caused by B. sorokiniana in all studied genotypes. In 2012, values of the leaf infection index varied from 21.88 (Oberek) to 48.12 (Hajduczek), in 2013 from 25.31 (Skald, Oberek) to 50.00 (STH 7910) and in 2014 from 21.88 (Oberek) to 50.00 (Hajduczek). In the experimental combination with B. sorokiniana, colonies of this fungus in the years 2012–2014 accounted for: 81.22%, 93.11% and 71.78%, respectively, and in control combination: 40.06%, 32.26% and 33.72%, respectively. The chemical analysis of grain of 9 barley genotypes obtained from plants in an experimental combination with B. sorokiniana in 2014, revealed the presence of sterigmatocystin in the genotypes: Hajduczek, Kormoran, Stratus and STH 7910. The sterigmatocystin concentration ranged from 5.39 ng·g–1 (STH 7910) to 67.05 ng·g–1 (Hajduczek). A statistically significant correlation was found between the value of the leaf infection index and the concentration of sterigmatocystin in the grain.
The aim of the presented work was the search for the relationship between the level of soluble carbohydrates in callus tissues of eight meadow fescue (Festuca pratensis Huds.) cultivars and their growth ability on media containing Bipolaris sorokiniana and Drechslera dictyoides metabolites. Calli were induced from mature grains using the method previously described (Płażek 1994). Callus obtained from single caryopsis was cut into three pieces which were weighted and put on the media with or without pathogen metabolites. Tissue selection was performed by means of “double-layer culture” technique (Lepoivre et al. 1986). After two-week culture in the darkness at temp. of 25°C the calli were weighted again. The sugar level in tissue was measured by means of colorimetric method of Klein & Weissman according to Snell (1961). Fresh mass decrease of calli developing on the media with fungus metabolites was observed by all studied object. The tolerance of calli of the tested cultivars to metabolites of both pathogens was significantly different. However, significant similarity between the tolerance of calli of particular varietes to both fungi was noted. The soluble carbohydrate contents in control tissue of all studied cultivars were similar and their values ranged between 2.4 and 3 % of fresh mass. B. sorokiniana metabolites caused a significant decrease of the sugar content in calli, while D. dictyoides metabolites did not decrease the sugar level.
The aim of this study was the evaluation of membrane permeability of callus cells of several Polish meadow fescue cultivars, which were treated with toxins of two leaf spot pathogens Bipolaris sorokiniana and Drechslera dictyoides. Fungus metabolites were obtained by the method described by Lepoivre et al. (1986). Calli of cultivars ‘Skrzeszowicka’, ‘Skawa’, ‘Westa’, POB 282, POB 383, KOA 186 have been selected on medium with metabolites for two weeks. Next the conductivity test of electrolyte leakage and of total ion contents in the examined tissue was done. On the base of this data the membrane permeability coefficients for each cultivar were calculated. Toxins of B. sorokiniana damaged the cell membranes more strongly than metabolites of D. dictyoides. The significant differences of several objects sensitivity to the influence of B. sorokiniana metabolites were stated. These differences were not observed in the case of the influence of D. dictyoides metabolites on the examined tissue.
Stem base health of spring barley cultivated under organic, integrated and conventional systems and fungal communities were studied. A worst plant health status was observed in the organic system. The macroscopic and subsequent mycological analyses revealed the occurrence of Bipolaris sorokiniana and Fusarium spp. The incidence of B. sorokiniana on stem bases was clearly dependent on a farming system, and the highest incidence of this pathogen was observed in the organic system. Also, in that system, Fusarium spp. were isolated more numerously in the beginning of tillering, but in dough stage B. sorokiniana was the most prevalent pathogen, and Fusarium spp. were more numerous in integrated and conventional systems. It is worth to note that organic conditions could be favourable to Gliocladium spp. Because of growing interest in ecology, excluding the use of pesticides and increasing popularity of biological disease control, these antagonistic fungi could be useful in organic systems.
Investigations were carried out in 1996 - 2000 in the Experimental Station of Cultivars Evaluation in Uhnin. Disease symptoms were recorded twice - in the seedling stage (18 in the Tottman's scale) and in milk ripe stage (77 in the Tottman's scale) of oat. The seedlings with root and sheath necrosis or plants with diseased stem base were obtained every year. The percentage of diseased seedlings ranged from 6.0 to 39.5, and percentage of older plants with necrotic stripes on lower intemodes ranged from 11.5 to 50.0. Results of mycological analysis of diseased plants showed that Fusarium spp., especially F. avenaceum and F. culmorum were isolated the most frequently, F. avenaceum was obtained in the seasons with different weather conditions. This indicates great tolerance of this fungus to temperature and humidity. In the seasons with high temperature F. culmorum was predominant. This species also can be tolerant to changing weather conditions. Warm and wet weather was favourable for oat infection by Bipolaris sorokiniana. Rhizoctonia solani was isolated from plants in milk ripe stage in each vegetation seasons, and from seedlings in years 1998 and 1999.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.