Silicon.induced physiological and biochemical changes under polyethylene glycol-6000 water deficit stress in wheat seedlings

Aim: The experiment was conducted to study the role of foliar application of silicon (SO2) under water deficit stress in wheat seedling stage by evaluating the physiological and biochemical parameters. Methodology:Application of silicon was made on 7th and 14th days after germination (DAG) to the seedlings of wheat (Triticum aestivum L.) varieties followed by imposition of polyethylene glycol-6000 (PEG) induced stress on 15th DAG. The samples were analyzed after 24 hours for relative water content (RWC), membrane stability index (MSI), total chlorophyll, proline, malondialdehyde (MDA), peroxidase (PDX), catalase (CAT) and silicon content. Results: Application of silicon followed by water deficit conditions increased RWC compared to PEG stress. There was a meagre percent variation in MSI in SiO2 and SiO2 + PEG treatments as compared to PEG and control. The Si02 treatment enhanced antioxidative enzymes in most cases. Positive correlations (P<0.01) were observed between enzymatic antioxidants, RWC and MSI, while MDA and proline displayed positive correlation (P<0.01). Silicon was able to ameliorate stress conditions as reflected by a significant rise in RWC (17.69%), MSI (55.80%), antioxidant enzyme level i.e. PDX (77.97%), CAT (89.32%) and a significant decline in proline content (36%). Interpretation: The foliar silicon treatment can be used as a promising alternative to mitigate water stress induced damage in wheat seedlings.