Transmission of tobacco mosaic virus in recirculating hydroponic system

The possible pathway of transmission of tobacco mosaic virus (TMV) from dis eased plants to healthy plants in two hydroponic systems, deep flow culture (DFC) and container culture (CC), was investigated in this study. The test ed plants were tobacco (Nicotiana tabacum cv. Samsun-nn and cv. Xanthi), to mato (Lycopersicon esculentum cv. Alchan), and hot pepper (Capsicum annuum cv. Dahong). The longevity in vitro and the dilution end point of the virus in the hydroponic solution were 5 days and 10(-4) (w/v), respectively. Whe n inoculum source plants and tested healthy plants were grown side by side in the same gully or containers, typical TMV symptoms appeared on the teste d plants in 2 weeks. The presence and concentration of the virus in the tis sues of the tested plants could be detected by DAS-ELISA. It was noticed th at roots of the inoculum source plants grafted to those of the tested plant s during growing period. However, when both inoculated plants and healthy p lants were grown separately, and their root tips were either removed or rem ained intact, no transmission of the virus from the inoculum source plants to the tested healthy plants occurred even though they shared the same recy cled nutrient solution. These results indicate that the virus in a recircul ating hydroponic system could be transmitted from virus-diseased plants to healthy plants mainly via root-tip grafting but was hardly transmitted thro ugh regularly renewed hydroponic nutrient solution. (C) 1999 Elsevier Scien ce B.V. All rights reserved.