Multiplication of tobacco mosaic virus in the duck-weed (Spirodela polyrhiza)

Abstract

(1) Multiplication of tobacco mosaic virus (TMV) on the duck-weed (Spirodela polyrhiza) was ascertained by the following experimental results.i) Duck-weeds were inoculated with TMV by a rubbing method. A small quantity of TMV was recovered 3 and 5 days after inoculation, but a larger quantity of the virus was estimated 10 days after from the inoculated fronds of duck-weed (Table 1 and 2).ii) Duck-weeds were infected with 1:1, 000 dilution of leaf juice from infected tobacco with TMV, but only rarely with 1:100, 000 dilution (Table 3).iii) The dilution end point of duck-weed juice, 20 days after being inoculated with TMV, was found to be 1:10, 000 (Table 4).iv) Juice from duck-weeds, 20 days after inoculation, was almost completely neutralized with TMV-antiserum (Table 5).v) One frond of duck-weed having 3 or more fronds was inoculated with TMV, and the inoculated frond was separated from the non-inoculated fronds. TMV was not recovered from these non-inoculated fronds, when separation from the inoculated frond was made 1, 3 or 5 days after the inoculation, but was recovered when was made 10 days after the inoculation. Besides, TMV was detected 30 days after the inoculation from young fronds which were newly formed from the inoculated fronds.(2) Besides the rubbing method, duck-weeds could readily be infected by shaking powerfully by a hand or by a shaker for 0.5 to 5 minutes in small bottles containing diluted TMV juice, carborundum powder and the plants (Table 6).