The effect of seed pretreatment with salicylic acid on manganese toxicity in Lepidum sativum L

Lepidium sativum L. is known as a medicinal plant. This plant is regarded as a cure for breast cancer due to antioxidant properties. The availability of manganese (Mn) in plants is governed by redox processes which depend upon pH and the presence of electrons. Excess Mn disturbs the metabolism of plants and inhibits the plant growth and oxidative stress is also induced which leads to the formation of reactive oxygen species (ROS) including superoxide, hydroxyl and hydrogen peroxide that could damage plant cells. Salicylic acid (SA) is a natural signal molecule which plays an important role in regulating a number of physiological processes and plant resistance to biotic and abiotic stresses. The protective function of SA includes the regulation of ROS, antioxidants, induction of gene expression, absorption and distribution of elements. In this investigation, the effects of different levels of salicylic acid (0, 0.01, 0.05, 0.1mM) on different concentrations of Mn (0, 250, 500, 800µM) were studied on Lepidium sativum. Results showed that addition of SA (0.01, 0.05, 0.1mM) improved the inhibition of induced calcium and magnesium uptake. Ascorbare content in leaf was increased by SA (0.01, 0.05, 0.1mM) but decreased by concentrations of 500 and 800 µM Mn. The proline content significantly increased in treatments of Mn and SA. The protein content decreased by 500 and 800 µM but the treatment of SA (0.01, 0.05, 0.1mM) increased the protein content under conditions of manganese toxicity.