Influence of zinc oxide nano particle on biophysical parameters, yield and grain zinc content of rabi sorghum (Sorghum bicolor)

Abstract

A pot experiment was conducted to find out the influence of zinc oxide nano particle on photosynthesis, shoot and root growth and yield in rabi sorghum (Sorghum bicolor var M-35-1) at Department of Crop Physiology, UAS, Dharwad, Karnataka. Experiment consisted of twelve treatments comprised of seed priming (200, 500 and 1000 ppm of nano ZnO and bulk ZnSO4), foliar application (200, 500, 1000, and 1500 ppm of nano Zno) and 1000 ppm of ZnSO4 (package of practice) with six replications was carried out. Nano ZnO 500 ppm of foliar spray recorded significantly higher shoot length (186.67), shoot dry weight (108.6), root length (83.33), root volume (310) and root dry weight (57.23) as compared to 1000 ppm bulk ZnSO4. Nano ZnO 500 ppm foliar spray recorded significantly higher chlorophyll content (1.39), SPAD values (49.57), photosynthetic rate (41.23), transpiration rate (0.19) and stomatal conductance (7.27) as compared to 1000 ppm bulk ZnSO4. Grain yield was 9.5 percent higher in 500 ppm of NFS and 1000 ppm NFS as compared to 1000 ppm of BFS. The gain zinc content was 5.6% higher in 500 ppm of NFS as compare with 1000 ppm of BFS. Compared to control both nano ZnO (18%) and Bulk ZnSO4 (11%) have higher zinc accumulation in their grains. The inhibitory effect was observed in nano ZnO concentration >1000 ppm reveals the toxicity and need for judicious usage of nano particles in foliar applications. This is the first report on the effect of nano ZnO particles on sorghum growth, photosynthesis, grain yield and zinc content.