摘要:

Pollution Pathology has emerged as a distinct discipline which deals with the impact of pollutants on plants and its disease causing agencies. Pollutants have been found to adversely affect not only the plants but also the phytopathogens and above all their pathogenesis. The hitherto scattered information on this aspect has been reviewed in the present write‐up.

ISSN:0323-5408    

DOI:10.1080/03235409809383273

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Mit Hilfe lichtmikroskopischer Untersuchungen (Phasenkontrast‐ bzw. Floureszenzmikroskopie) wurde die Entwicklung des PilzesPyrenophora teres(Sacc.) Shoem. auf dem Blatt sowie im Blattgewebe von anfälligen und resistenten Gerstengenotypen analysiert. Die Beobachtungen konzentrierten sich auf die qualitative und quantitative Erfassung spezifischer Infektionsstrukturen wie gekeimte Konidien, Keimhyphen, Appressorien, intrazelluläre Vesikel und Hyphen sowie auf die von der Wirtspflanze nach Kontakt mit dem Pathogen ausgelösten Abwehrreaktionen (z. B. Papillenbildung, Zellwandauflagerungen, Zytoplasmaaggregation). Im frühen Stadium der Infektion konnten zwischen den anfälligen und resistenten Genotypen keine Unterschiede hinsichtlich der pilzlichen Entwicklung beobachtet werden. Der Pilz war in der Lage, auch die Epidermiszellen von Haferblättern(Avena strigosd)zu penetrieren, ohne sich jedoch weiterzuentwickeln. Die Tatsache, daß bei den resistenten Genotypen die Entwicklung der Pilzhyphen im Blattmesophyll stagnierte, nach Pilzbefall induzierte Abwehrreaktionen der Pflanzenzellen aber nicht beobachtet wurden, läßt vermuten, daß für die unterschiedlichen Resistenzreaktionen der Pflanzen physiologische und biochemische Prozesse verantwortlich sein müssen.

ISSN:0323-5408    

DOI:10.1080/03235409809383274

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Rhizopus oryzaeachieved a peak amylase production within 6 days of culture for starch yeast extract (SYE) medium and 8 days for yeast extract (YE) medium through the 20 days period of incubation, Maximum amylase activity by the fungus occurred prior to maximum production of mycelial biomass both in the SYE and YE media. Production of amylase was not related to total mycelium produced but was directly related to the type of carbon source in the medium. Starch and glucose were the best carbon sources for amylase production whereas maximum mycelial biomass was recorded in the medium containing sucrose as the sole carbon source. The maximum mycelial biomass and amylase activity were recorded at 30°C and pH 6. The fungus as a prolific amylase producer could be of industrial use in some fermentation processes.

ISSN:0323-5408    

DOI:10.1080/03235409809383275

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Different developmental ages ofMicroplitis rufiventrisKok. teratocytes were exposed to a topical dose (70 μg/5 μl) of an anti‐juvenile hormone (Precocene II) viaSpodoptera littoralislarvae and inspected just prior parasitoid egression. Application of PII exerted significant reduction in both cell number and size. Whatever the teratocyte age at treatment, treated host larvae contained smaller sized cells than untreated ones,i.e.,the effect seems to be permanent. The results suggested that: (1) the teratocyte may be involved in sequestering host's juvenile hormone, (2) healthy teratocytes may act in inhibiting the ability of host to produce melanin, and (3) PII‐treatment might have an effect on the absorptive function of the teratocytes.

ISSN:0323-5408    

DOI:10.1080/03235409809383276

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The effects of superparasitism on the size and number of teratocytes (giant cells released by the serosa of braconid eggs after hatching) found in the hostSpodoptera littoralisat the completion of development of the solitary endoparasitoidMicroplitis rufiventriswere assessed. Although the number of teratocytes increased, on average, with parasitoid load (1, 2 or 3 parasitoid eggs), this increase was lower than predicted, based on the number of parasitoids (i.e., is not proportional to parasitoid load). Similarly, the size of the teratocytes decreased as a function of parasitoid load. The total volume of the teratocytes (mm3) is reduced by 39.1 and 66.4% in hosts parasitized twice and three times, respectively. It is concluded that, in superparasitized hosts, some form of competition likely takes place among the teratocytes, or between these cells and the first‐hatched larva, possibly through the action of a chemical (released by the latter) that inhibits the growth of teratocytes from supernumerary parasitoids. In singly parasitized hosts 73.2, 17.8 and 9.0% of total teratocytes were found in hosts abdomen, head capsule and thoracic regions, respectively. In superparasitized hosts, the cells tended also to collect in the posterior region of the host but with fewer number of cells in the head capsule. It seems that the teratocytes possibly act as a biological regulating factor to adjust host's endocrine system for successful development of the parasitoid.

ISSN:0323-5408    

DOI:10.1080/03235409809383277

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Hartleb, H., Heitefuss, R., Hoppe, H.‐H. (Eds.): Resistance of Crop Plants against Fungi. Gustav Fischer Verlag Jena, Stuttgart, Lübeck, Ulm, 1997; 544 S., 67 Abb., 64 Tab., Preis: 198,‐ DM; ISBN: 3–437–35338–1

ISSN:0323-5408    

DOI:10.1080/03235409809383278

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0323-5408    

DOI:10.1080/03235409809383272

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor