Kumar, ShaileshM, SEETHALAXMI2023-07-062023-07-062021M/BPP/390/2019-2020https://krishikosh.egranth.ac.in/handle/1/5810198011Wheat, the king of cereals is the world’s important crop occupying major diet of the people. Salinity stress is the serious problem in arid and semi arid parts of the world. On a global scale, 20-33% of cultivated areas and 50% of irrigated area have been affected by salt stress. Wheat seedlings are more sensitive towards soil salinity. In order to increase the productivity of crop to meet out the growing population, nanotechnology have been proven as the emerging trend to alleviate salinity stress. ZnO nanoparticles due to its unique properties acts as fertilizer releasing Zn, a potential micronutrient through which adverse effects of salinity could be mitigated, thus promoting growth and development. Also, the efficiency of nanoparticles have been proved in comparison with their bulk form (ZnSO4). The current studies entitled, “Efficacy of nano Zinc oxide on physiology of wheat (Triticum aestivum L.) under normal and salinity stress condition” was performed with three objectives viz. to find out the adverse effects of salinity on growth and development of wheat seedlings, to recognize the ameliorating effect of ZnO nanoparticles on morpho-physiological traits and finally to prove the excellence and efficiency of nanoparticles over their bulk forms (ZnSO4). In first objective, thirty genotypes viz., WB 02, HPYT 424, RAU W 3001, BHU 31, RAU W 105, HD 2733, HPYT 452, RAU W 4041, HPYT 483, HD 2967, SONALIKA, RAU W 3060, RAU W 9010, HPYT 458, RAU W 9025, NEST 17-39, ESWYT 123, BHU 25, HD 2824, HPYT 405, NEST 18-5, NEST 18-25, NEST 18-16, RAU W 6007, HPYT 429, HPYT 480, RG 1, PBW 343, RAU W 7016 and NEST 18-33 were tested at a salinity level of 4.2 dSm-1 (EC). The genotype screening was performed based on emergence percentage, seedling length, seedling dry weight, seedling vigour I and II in 15-day-old plants and a contrasting set of genotypes have been selected. Salinity have highly reduced the aforementioned parameters where the reduction percent in all the above metrics was high in ESWYT 123 and low in NEST 18-16. In second objective, seed priming have been done with seeds of selected set of genotypes with ZnO nanoparticles at different concentrations (50, 100, 250, 500 and 1000 ppm). The genotypes were grown in both normal and saline soil conditions and morpho-physiological traits like emergence percentage, shoot and root length, shoot and root dry weight, seedling vigour I and II, SPAD value have been measured in 15-day-old seedlings of both the genotypes. The results revealed that ZnO nanoparticles at low concentrations have enhancement effect on those previously mentioned parameters at 50 ppm and 100 ppm concentrations in both normal and saline soil conditions. There was also a promoting effect with 250 and 500 ppm concentrations which were a bit less in efficiency than the former. Nanoparticles at high concentrations have exhibited negative effects indicating phytotoxicity. Thus, the maximum effect was observed with 100 ppm concentration, ameliorating the effects of salinity stress. In third objective, the efficacy of ZnO nanoparticles was compared with their bulk form (ZnSO4) on morphological (plant height, dry matter accumulation, leaf area and specific leaf weight), physiological (RWC, MSI, photosynthetic pigments, SPAD value, chlorophyll stability index, lipid peroxidation) and biochemical (antioxidant enzymes like SOD, peroxidase, catalase and proline) parameters of 30-day-old wheat seedlings of both the genotypes. Salinity stress had negative impacts on all those parameters stated above which could be alleviated or mitigated by both ZnO nanoparticles and ZnSO4. The alleviating potential was greater in nanoparticles when compared with their bulk form thus, proving their performance excellence. The present findings have concluded that salinity had adverse effects on seedling growth and development of wheat crop which could be alleviated by seed priming with ZnO nanoparticles. ZnO nanoparticles at 100 ppm concentration i.e. at low concentration had promoting effect on morpho-physiological and biochemical parameters of wheat. Also, nanoparticles have been proven to be more efficient than the bulk forms. Therefore, nanoparticles could be utilized as fertilizers or stress alleviators with better results in the near future.EnglishThesis