班入りタバコ

Towards a better understanding of the relationship between virus multiplication and chloroplast, studied were conducted on the cucumber mosaic virus (CMV) multiplication in white (W) and green (G) areas of variagated leaves of tabacco plants (Nicotiana tabacum cv. Samsun Nc). 1. The infectivity of extracts from W and G was first detected at 24 hours after inoculation and increased with time almost in parallel on both areas, reached peaks at 5 days and then decreased. Virus concentration in W was always 1.7-3.9 times higher than that in G. 2. RNase activity in healthy leaves and inhibitory effect of CMV-excluded-supernatant-solution prepared from the inoculated leaves on CMV infectivity were higher in W than in G. 3. The virus movement from the inoculated G to opposite uninoculated W was detected 6 and 4 days after inoculation in attached and detached leaves, respectively. The virus movement from G to G was retarded 1 to 3 days than that from G to W. 4. Electron microscopic observation of W and G from leaf tissues 4 days after inoculation revealed that CMV particles were not in the form of crystalline array or large masses but scattered with ribosomes in the cytoplasm of mesophyll tissue. 5. From the above results, the difference in CMV concentration between W and G is considered to be caused mainly by the differential photosynthetic ability which affects the sensitivity of host tissues to virus infection and multiplication.