The relationship between acquired resistance to Peronospora tabacina in Nicotiana tabacum and soil nitrogen levels

Abstract

When plants (Nicotiana tabacum L. cv. Virginia Gold) were supplied with suboptimal levels of nitrogen, the acquired resistance to blue mould (Peronospora tabacina Adam) evoked by injection of spore suspensions of the same pathogen into stems was associated with dwarfing, reduction in leaf areas, nitrogen deficiency-like symptoms, and premature senescence. However, when plants were supplied with adequate nitrogen, no morphological changes were associated with acquired resistance. The protective effect of stem injection against subsequent leaf infection was shown to be persistent and not affected by plant vigour, age, or soil nitrogen level. The protective effect of stem injection against subsequent leaf infection was shown to be persistent and not affected by plant vigour, age, or soil nitrogen level.