-9- 



postfixed in 1-2% OsO., dehydrated with acidified 2,2- 

 dimethoxypropane (Muller and Jacks, 1975), and embedded in 

 Spurr's low-viscosity medium (Spurr, 1969). Sections were made 

 with either a glass or a diamond knife and were stained with 

 potassium permanganate, uranyl acetate, and lead citrate ( Ko 

 and Chen, 1982) . 



The identities of ORSV, CyMV, bean yellow mosaic virus 

 (BYMV), and cucumber mosaic virus ( CMV ) were confirmed in tests 

 using antisera to the respective viruses. Expressed sap was 

 tested against antisera to the respective viruses in sodium 

 dodecyl sulfate (SDS) double radial immunodiffusion tests as 

 described previously (Purcifull and Batchelor, 1977; Zettler et 

 al . , 1978; Kuwite and Purcifull, 1982; Wisler et al. , 1982). 

 The immunodiffusion medium used contained 0.5% SDS, 1% NaN,, 

 0.8% Noble agar. Slicing bioassays were used to identify the 

 CyMV and ORSV on the indicator hosts, Cassia occidentalis and 

 Gomphrena globosa , respectively (Appendix I). Conventional 

 bioassay techniques (Lawson and Brannigan, in press) were used 

 for CMV and BYMV. Cucumber mosaic virus infections were confirmed 

 by inoculation of several hosts, including cucumber ( Cucumis 

 sativus 'Marketer'), tomato ( Lycopersicon esculentum ) , 

 Nicotiana benthamiana , N . x edwardsonii , N. glutinosa , N . 

 tabacum Xanthi nc. , cowpea ( Vigna unguiculata ) , and V^ radiata . 

 Bean yellow mosaic virus infections were confirmed by 



