-18- 



when labelled ORSV or normal serum was used. Reactions of 

 identity were obtained between antigens in expressed sap and 

 antigens of a known CyMV isolate when tested against CyMV 

 antiserum in SDS immunodiffusion tests. In the bioassay, CyMV 

 infection caused dark brown spots on the cotyledons and 

 leaflets of Cassia occidentalis as described by Lawson and 

 Brannigan (in press). 

 Cucumber Mosaic Virus 



Color breaks on the flowers (Fig. 14) and chlorosis on the 

 leaves were found in the Phalaenopsis orchid infected with CMV 

 (Fig. 15). Angular shaped, densely stained inclusions of 

 variable sizes (Fig. 16) were seen in the tissues of this 

 plant. In some instances, the inclusions had clear internal 

 areas, similar to those noted by others for CMV and other 

 cucumoviruses (Christie and Edwardson, 1977). The same type of 

 inclusion was also found in the other systematically infected hosts, 

 such as N^ x edwardsonii (Fig. 17). Inclusions were much more 

 abundant in mesophyll than epidermal cells of the orchid flower 

 or leaf tissue. They also occurred much more abundantly in the 

 newly emerged immature leaves. Thin sections revealed these 

 inclusions to consist of massive crystalline arrays of densely 

 packed virus particles (Fig. 18) (Christie and Edwardson, 

 1977; Russo and Martelli, 1973). Such inclusions fluoresced 

 when exposed to TRITC-label led CMV antiserum (refer to chapter 

 3). Expressed sap of CMV-infected tissues reacted homologously 

 in immunodiffusion tests with CMV antiserum produced by Kuwite 



