Résumé
Disturbances in mitotic division in tomato plants in response to viral infection by potato virus Y [PVY] and/or tobacco mosaic virus-E [TMV- E] were determined after 1, 5, 10, 15, 25, 35 and 45 days post inoculation. The results revealed that either PVY or TMV significantly lowered the mitotic division in tomato plants as indicated by the comparatively lower mitotic index than the respective control. PVY was much more effective than TMV-E. Complete arrest of mitotic division was recorded at 45 days post inoculation with either viruses. Mixed infection insignificantly affected mitotic division of tomato plants. Under all experimental conditions the percentage prophase increased with continued growth, whereas, the percentage of the other phases decreased
Sujets)
Index mitotiqueRésumé
Four antibiotics viz. ampicillin, chloramphenicol, penicillin G. sodium and streptomycin sulfate were tested for their antiviral activities against potato virus Y [PVY] in a susceptible host, Datura metel, which reacts by mosaic symptoms when inoculated with PVY in vitro and in vivo. The results revealed that ampicillin and chloramphenicol did not exhibit potential antiviral activities in vitro and in vivo. So, they may not be useful in controlling PVY infection. Penicillin G. sodium did not significantly affect PVY infectivity in vitro except at 2000 ppm for 180 minutes, while streptomycin sulfate caused significant and highly significant reduction at 1000 or 2000 ppm for 60 and 180 minutes. In vivo neither penicillin G. sodium nor streptomycin sulfate caused a significant reduction in PVY infectivity. Twenty-four hours preinoculation spraying of Datura metel with penicillin G. sodium and streptomycin sulfate delayed the appearance of symptoms, while postinoculation treatment hastened the appearance of mosaic symptoms. So, penicillin G. sodium and streptomycin sulfate did not act as inhibitors of PVY infections