Effect of Time of the Day on the Susceptibility of Plants
A diurnal effect on the susceptibility of plants has been established with a number of plant-virus combinations. In general, the susceptibility of plants is low in the early morning (at 6 h) and steadily rises until it reaches a maximum in the afternoon (between 14 and 16 h). This variation is not influenced by environmental conditions. In this exercise, the effect of the time of day on the susceptibility of leaves of the cultivar Pinto of French bean (Phaseolus vulgaris) to tobacco mosaic Tobamovirus (TMV) is studied.