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Two outbreaks of the egg drop syndrome were observed in quail flocks maintained on a farm together with chickens. The decrease in egg production ranged from 10.6 per cent to 50.6 per cent, and the number of soft-shelled eggs increased with the decline in egg production. In both the outbreaks haemagglutination inhibiting antibodies to EDS-76 virus were detected. Fluorescent viral antigen specific to EDS-76 virus was also detected in the lining epithelial and glandular cells of the uterus. 相似文献
3.
The relative amounts of primary and secondary sulfates in atmospheric aerosols and precipitation can be estimated from measurements of the stable oxygen isotope ratios. The oxygen-18 content of sulfates formed in power plant stack gases before emission into the atmosphere is significantly higher than that of sulfates formed from sulfur dioxide after emission. Results show that 20 to 30 percent of the sulfates in rain and snow at Argonne, Illinois, are of primary origin. 相似文献
4.
The independent modes of action of diuron and atrazine on the photochemical activities of chloroplasts (In vivo and in vitro) from the leaves of crop plants Pisum sativum and Pennisetum typhoides and the weeds Amaranthus viridis and Cyperus rotundus were investigated. Hill reaction activity (DCPIP photoreduction) of in vivo chloroplasts (chloroplasts isolated from herbicide-sprayed plants) was unaffected by treatment at sublethal or intermediate levels of diuron or atrazine while that of in vitro chloroplasts (chloroplasts incubated in the required herbicidal concentration) was severely inhibited. The ferricyanide catalyzed noncyclic photophosphorylation was markedly reduced in both the in vivo and in vitro chloroplast systems. N-Methyl phenozonium sulfate (PMS)-mediated cyclic photophosphorylation was inhibited in the in vivo system while a pronounced enhancement of activity was noticed in the in vitro chloroplasts. The rate of NADP+ photoreduction was severely inhibited in the in vitro chloroplasts. The unaffected in the in vivo system. The herbicidal effects on the photoreactions of isolated chloroplasts were compared with chloroplasts isolated from herbicide-sprayed plants. 相似文献
5.
Y. Antignus M. Lapidot N. Ganaim J. Cohen O. Lachman M. Pearlsman B. Raccah A. Gera 《Phytoparasitica》1997,25(4):319-330
Received April 24, 1997; received in final form June 29, 1997. Symptoms resembling tomato spotted wilt virus (TSWV) infections
were documented among ornamental and vegetable crops in commercial greenhouses and open fields in Israel. Plants exhibiting
these symptoms were collected from January 1992 to December 1996. Among cultivated plants analyzed for TSWV by enzyme-linked
immunosorbent assay (ELISA), 19 species representing five families were found to be infected; natural infection was also recorded
in six plant species of weeds. Virus identity was characterized by host range, serology and electron microscopy. Serological
reaction with the isolates, found in Israel, using antisera from different sources as well as the sequence analysis of the
nucleocapsid gene, demonstrated that the Israeli isolates of TSWV are a member of tospovirus serogroup I, type I (BR-01 strain).
No virus transmission was found in seeds collected from virus-infected vegetable and ornamental crops. A non-radioactive molecular
probe derived from the cloned nucleocapsid isolate enables specific detection of the virus in crude sap from infected plants.
The detection of TSWV in Israel constitutes a severe potential threat to the ornamental and vegetable industry. 相似文献
6.
It has been widely hypothesized that a warmer climate in Greenland would increase the volume of lubricating surface meltwater reaching the ice-bedrock interface, accelerating ice flow and increasing mass loss. We have assembled a data set that provides a synoptic-scale view, spanning ice-sheet to outlet-glacier flow, with which to evaluate this hypothesis. On the ice sheet, these data reveal summer speedups (50 to 100%) consistent with, but somewhat larger than, earlier observations. The relative speedup of outlet glaciers, however, is far smaller (<15%). Furthermore, the dominant seasonal influence on Jakobshavn Isbrae's flow is the calving front's annual advance and retreat. With other effects producing outlet-glacier speedups an order of magnitude larger, seasonal melt's influence on ice flow is likely confined to those regions dominated by ice-sheet flow. 相似文献
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