Uptake and translocation of foliar-applied glycinebetaine in crop plants

Abstract

Glycinebetaine is known as an osmoprotectant which is accumulated in certain plant species under salt and drought stresses. Exogenous applications of glycinebetaine on crop plants unable to synthesise glycinebetaine is a possible approach to overcome the environmental limitations of crop production. Information about the capability of plants to take up and translocate foliar-applied glycinebetaine is, however, limited. In this study, glycinebetaine solution, with and without surfactants, was exogenously applied to foliage of summer turnip rape ( Brassica rapa L. ssp. oleifera), soybean [ Glycine max (L.) Merr.], pea ( Pisum sativum L.), tomato ( Lycopersicon esculentum Mill.), and spring wheat ( Triticum aestivum L.) in greenhouse experiments. Uptake of glycinebetaine was monitored using high-performance liquid chromatography. [ 14C]glycinebetaine was applied to leaves of turnip rape plants and translocation to other plant organs was monitored autoradiographically. [ 14C]glycinebetaine was translocated to roots within two hours of application. One day after application labelled glycinebetaine was translocated to all plant parts of turnip rape plants. The results indicate that plants are able to translocate foliar-applied glycinebetaine from their leaves to other organs, and that the use of surfactants accelerates the penetration of foliar-applied glycinebetaine. According to our results glycinebetaine is quite inert end-product in plant cells being mainly phloem-mobile. Moreover, environmental conditions are shown to affect the uptake and translocation rates of foliar-applied glycinebetaine.