CAULIFLOWER MOSAIC-VIRUS PARTICLES ALTER THE SENSITIVITY OF ARABIDOPSIS-THALIANA SEEDLINGS TO 2,4-D

Seed obtained from Arabidopsis thaliana plants can be germinated on ag ar plates and seedlings remain viable in the presence of low concentra tions of the growth substance 2,4-D. However, when seed obtained from plants infected with cauliflower mosaic virus (CaMV) was similarly ger minated in 2,4-D, seedlings developed cotyledons but then rapidly blea ched and senesced. Bleached plants were also observed when purified pa rticles of CaMV were mixed with seed obtained from healthy plants and germinated in 0.23 - 2.3 muM 2,4-D. The growth substance alone was fou nd to cause bleaching only when increased above 2.3 muM. The effect of CaMV and 2,4-D on Arabidopsis was still observed after UV-inactivatio n of virus particles suggesting that the effect was caused by a change in the sensitivity of Arabidopsis to 2,4-D rather than virus replicat ion.