Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 11

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  canker
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Citrus bacterial canker, caused by Xanthomonas citri subsp. citri (Xcc), is a destructive disease. So far, the chemicals used to control this pathogen are either ineffective or harmful to the environment. To improve control of this disease, lime (Citrus aurantifolia) were treated with L-arginine, L-methionine, L-ornithine, and distilled water. Plants were inoculated with Xcc, 48 hours post treatment. Lesion diameters of inoculated leaves were evaluated four weeks after inoculation with a bacterial suspension. Changes in β-1,3-glucanase transcript levels and activity of antioxidant enzymes, catalase, peroxidase, and phenylalanine ammonia-lyase were investigated at 48 hours post treatment and 24, 48, and 72 hours post inoculation. Based on the results of phenotypic, antioxidant enzyme activity and a molecular study of the stressed plants, it was found that those plants treated with the amino acid methionine significantly increased the plant induced resistance as well as decreased the severity of disease by reducing necrotic lesion size.
During a survey on fungi associated with decline symptoms on grapevine cultivars growing in Kurdistan region of Iraq, several isolates of Botryosphaeria species were encountered. All isolates were identified as Botryosphaeria parva Pennycook and Samuels. Pathogenicity test for isolate DKI 1 was performed on two cultivars, Taefi and Rashmew. Under greenhouse conditions, one-year grape rooted cuttings were inoculated with the pathogen isolate by two methods, injecting the spore suspension into the green shoots and by artificial inoculation of wounded shoots with mycelial mat. The highest canker length (15.0 mm) was produced after four months on the shoots of the Taife cultivar artificially inoculated with mycelial mat of the pathogen. Under field conditions, two methods of inoculation were adopted, wounding the green shoots and drilling a hole in the arms of mature vine, followed by inoculation with mycelial mat. The highest canker length (11.17 mm) was obtained after 5 months on wounded shoots of the Rashmew cultivar and with a significant difference from the Taefi cultivar. The pathogen caused a reduction in fresh and dry weight of green shoots and roots compared with the non-inoculated control. This is the first report on B. parva in Iraq.
The genetic basis of the resistance of the common cypress to Seridium cardinale was investigated in the environmental condition of Central Italy. The cortical canker caused by the fungus affects the common cypress since the 1970’s in Europe and the genetic improvement for the resistance is considered an effective tool to cope with the bark canker epidemics. General and specific combining abilities of thirty mother plants were estimated by means of a North Carolina II mating design including four cypress clones as testers showing divergent degree of canker resistance. The strong differences among testers and general combining effects showed that the character under investigation has an additive genetic control. The best combinations were identified within the families from the crosses with the resistant tester. The results however showed that an early classification of the mother trees, based on a simple unreplicated resistance screening test, is not effective to predict the behaviour in crosses. Replicated screening tests based on morpho-physiological and chemical characteristics are suggested, because the bark canker resistant traits is not sufficiently stable in cypress trees.
Thirty-three type A strains of G. abietina from diseased shoots or needles of P. sylvestris, P. nigra and P. armandii and three strains of Brunchorstia pinea var. cembrae from P. mugo were isolated from four regions of Poland differing with respect to climatic conditions. Genetic polymorphism of the mitochondrial small subunit rRNA (mtSSU rRNA), ribosomal RNA fragment including ITS1, 5.8S and ITS2 and glyceraldehyde phosphate dehydrogenase (GPD) gene was examined by the PCR-RFLP method. Genetic distance was ascertained with respect to B. pinea var. cembrae strains from G. abietina isolated from the examinedpine species (average Nei coefficient 0.137). The smallest genetic distance occurred between the strain groups of G. abietina isolated from P. nigra and P. armandii (0.059) and P. nigra and P. sylvestris (0.061), whereas the highest occurred between the groups of strains deriving from P. armandii and P. sylvestris (0.096). The impact of geographic distance on genetic distance between groups of strains from individual regions has been shown. G. abietina strains originating from mountainous areas were more distanced genetically (on average 0.031) from populations from other regions (Nei genetic distance 0.023). The main factors influencing genetic differences of the pathogen were specificity with respect to the species of the host plant and climate conditions, whereas geographic distance had lesser significance.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 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.