Salicylic Acid Prevents the Damaging Action of Stress Factors on Wheat Plants

We investigated the effect of salicylic acid (SA) on plant resistance to environmental stress factors. Treatment of wheat plants with 0.05 mM SA increased the level of cell division within the apical meristem of seedling roots which caused an increase in plant growth. Phytohormones are known to play a key role in plant growth regulation. It was found that the SA treatment caused accumulation of both ABA and IAA in wheat seedlings. However, the SA treatment did not influence cytokinin content. We suppose, that the protective and growth promoting effects of SA are due to the phenomenon described above. The SA treatment reduced the damaging action of salinity and water deficit on seedling growth and accelerated a restoration of growth processes.Treatment with SA essentially diminished the alteration of phytohormones levels in wheat seedlings under salinity and water deficit. The SA treatment prevented the decrease in IAA and cytokinin content completely which reduced stress-induced inhibition of plant growth. Also, high ABA levels were maintained in SA treated wheat seedlings which provided the development of antistress reactions, for example, maintenance of proline accumulation. Thus protective SA action includes the development of antistress programs and acceleration of normalization of growth processes after removal stress factors.