Use of plant stress response for increasing plant biomass, harvest and production of biologically active compounds

Abstract

Seed germination and seedling growth can be improved by the pre-sowing seed treatment with cold plasma (CP) and electromagnetic field (EF), however the molecular mechanisms of these effects remain elusive. Our experiments were performed on perennial woody species (Morus nigra L., Rhododendron smirnowii Trautv., Picea abies), perennial medicinal plants (Echinacea purpurea (L.) Moench, Trifolium pratense L.) and annual plant species (Helianthus annuus, Raphanus sativus; Fagopyrum esculentum). We report novel findings important for understanding of CP and EF effects: (i) the extent of the observed effects on germination is dependent on seed dormancy status characterized by seed hormonal balance (the most important is ratio between absisic acid and gibberrelins); (ii) seed treatments with CP and EF induce changes in the amount of secondary metabolites and antioxidative activity in tissues of growing plants. That is an important part of plant stress response leading to increased seedling establishment, defense and communication potential; (iii) results of differential proteomic analysis performed on H. annuus seeds and leaves of seedlings showed that CP and EMF treatments induce changes in expression of more than 30 proteoforms in seeds and more that 100 proteoforms (mostly involved in photosynthesis) in leaves, indicating that plant stress response induced by seed treatment with CP and EF involves multiple changes in plant gene expression, (iv) The results of the long-time field observations showed that CP and EMF effects on P. abies growth persist for more than 4 years and have impact on plant UVB stress response; seed treatments almost twice increased biomass production and seed harvest of F. Esculentum.