Trehalose pretreatment induces drought tolerance in radish (Raphanus sativus L.) plants: some key physio-biochemical traits

Abstract

Trehalose, a natural disaccharide, has already been under the attempt of improving stress tolerance in a variety of crop plants. Keeping in view its role in stress tolerance, the effectiveness of seed presoaking with trehalose (25 mM) was tested in radish (Raphanus sativus L.) plants grown under water stress and non-stress conditions. Two radish cultivars namely Manu and 40-day were grown under control (normal watering) and water-deficit (60 % field capacity) conditions. After 45 days of drought stress treatment, a significant suppression was observed in plant fresh and dry biomass, chlorophyll (a and b), relative water content (RWC), rate of photosynthesis (Pn), sub-stomatal CO2 concentration (Ci), and shoot and root K+, Ca2+ and P, while a rise in water-use efficiency (WUE), total soluble sugars (TSS) leaf free proline and glycinebetaine (GB) contents, activities of superoxide dismutase (SOD) and peroxidase (POD) in both radish cultivars under water stress. However, trehalose application caused a significant increase in plant fresh and dry biomass, chlorophyll a content, TSS, Pn, WUE, free proline contents as well as the activity of SOD enzyme. Of both radish cultivars, cv. Manu was relatively better in chlorophyll b content, TSS and Ci, while cv. 40-day in shoot K+ and P contents. However, pattern of decrease or increase was same for all other tested attributes in both radish cultivars. Overall, seed pre-sowing treatment induced growth improvement of radish plants under water stress that was found to be associated with a significant increase in chlorophyll a content, Pn, WUE, TSS, free proline contents as well as the activity of SOD enzyme in both radish cultivars.