THE BEHAVIOUR OF GRAPEVINE UNDER VIRUS INFECTION AND DROUGHT STRESS COMBINATION

Abstract

Potted Grapevine fleck virus-infected and virus-free grapevine belonging to V. vinifera L., Tămâioasă românească selection, have been subjected to progressive water deficit. At a daily thermal amplitude of 23.7-30.3°C, the soil temperature did not exceed 29.8°C. After 37 days the shoots of the plants were completely dry, the soil moisture reaching 4.8%. The difference in leaf angle values between drought and control plants was higher in infected grapevines as compared to healthy ones, at the beginning of plant wilting. The total water content decreased during the intensification of the wilting degree of the leaves, significant differences comparatively to the control in the virus-free plants being registered. Stomata opening decreased significantly in water stressed virus-infected plants at the onset of wilting, as compared to healthy water stressed plants. The water deficit did not influence significantly the content of assimilating pigments either in healthy or virus-infected plants.