Kari Jokinen

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.

Growth response of pea and summer turnip rape to foliar application of glycinebetaine

It has been reported that foliar application of glycinebetaine reduces the effect of abiotic stresses on crops, including tobacco (Nicotiana tabacum L.), soybean [Glycine max (L.) Merr.], and maize (Zea mays L.), especially during the recovery period. The aims of this study were to determine the effect of foliar application of glycinebetaine on biomass accumulation and photosynthetic capacity of turnip rape (Brassica rapa L. ssp. oleifera) and pea (Pisum sativum L.). Experiments were carried out in a greenhouse and in the field, and records were taken on differentiation and emergence of floral organs. Biomass accumulation, relative growth rate (RGR), specific leaf area, leaf chlorophyll content, and nitrogen uptake were also measured for pea. In the experiment in the greenhouse, glycinebetaine application increased relative growth rate of both crops, especially when drought‐stressed and when recovering from drought. Application of 0.20 M glycinebetaine increased RGR of pea, recovering from drought, by 13%...