Acta Botanica Croatica, Vol. 40 No. 1, 1981.
Original scientific paper
Effect of Senescence on Lesion Formation and the Level of Induced Resistance in Samsun NN Plants Infected with TMV. I. Experiment with Changing Photoperiod
Kazimierz A. Miczyński
; Poljska
Abstract
Inoculation of Samsun NN tobacco leaves with TMV results in a hypersensitive reaction so that local necrotic lesions appear. Afterwards the whole plant reaches a status of resistance to superinfection with the same virus. This specific resistance manifests itself in the reduction of the size of necrotic lesions arising on the leaf after superinfection.
The level of specific resistance depends on many different factors, among which on the age of the infected plant or even of particular leaves. Older leaves are usually more resistant. In the present study the author stimulated the natural process of senescence by raising the plants under unfavourable conditions of a short photoperiod. It was shown that the plants influenced by a short photoperiod developed, after TMV inoculation, a much higher level of induced resistance.
The number of lesions is not a good index of the level of induced resistance. The results show that a good index of the level of induced resistance can be provided by modal values of the frequency distribution curves of lesion diameters. They are a better index than the arithmetic means because they also give an idea on the dynamics of lesion growth.
Keywords
Hrčak ID:
158406
URI
Publication date:
31.12.1981.
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