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ABSTRACT: Plant growth regulators are an immense group of substances that have the ability to alter growth pattern of plants and can be used for improving plant growth and productivity. A study was conducted in the Xilin Gol grassland of Inner Mongolia, China, to ascertain the growth and biomass production of Stipa krylovii in response to exogenous application of different growth regulators at various concentrations viz. naphthalene acetic acid (NAA), 6-benzylaminopurine (6-BA), brassinosteroid (BR), sodium nitrophenolate (SNP) and forchlorfenuron, and gibberellic acid (GA3). Application of growth regulators significantly enhanced the growth and biomass production of S. krylovii. The height of vegetative shoot was enhanced mostly by the application of 100 mg L-1 GA3, while, height of reproductive shoot was increased by 25 mg L-1 6-BA, 100 mg L-1 SNP + 5 mg L-1 forchlorfenuron and 50 mg L-1 SNP + 2.5 mg L-1 forchlorfenuron as compared to control. Fresh biomass was enhanced by the application of 0.02 mg L-1 BR, 10 mg L-1 SNP + 0.5 mg L-1 forchlorfenuron and 50 mg L-1 SNP + 2.5 mg L-1 forchlorfenuron. Application of 5 mg L-1 6-BA and 50 mg L-1 SNP + 2.5 mg L-1 forchlorfenuron proved to be more beneficial in improving dry biomass of S. krylovii, as compared to control. In conclusion, exogenous application of different growth regulators improved growth and biomass production of S. krylovii. Furthermore, application of SNP + forchlorfenuron and 6-BA was more effective.

ABSTRACT: Abiotic stresses and poor biomass accumulation are chief constraints to accomplish potential yield in Leymus chinensis. An experiment was conducted to improve biomass and correlation of biomass accumulating attributes with photosynthetic pigments, osmotic substances and antioxidants under foliar application of different plant growth substances. The experiment was conducted at inner Mongolia Xilinguole, China, using a Randomized Complete Block Design and 5 replications. The treatments consisted of water (control); BA5 = application of BA (6-benzylaminopurine) at 5 mg L-1; BA25 = application of BA at 25 mg L-1; BA50 = application of BA at 50 mg L-1; BR0.02 = application of BR (brassinosteroid) at 0.02 g L-1; BR0.2 = application of BR at 0.2 mg L 1; BR2 = application of BR at 2 mg L-1; GA10 = application of GA (gibberellic acid) at 10 mg L-1; GA50 = application of GA at 50 mg L-1 and GA100 = application of GA at 100 mg L-1. Application of all plant growth substances significantly improved biomass, osmotic adjustments, photosynthetic pigments and antioxidant activities compared to control. However, the most promising results were found with 0.2 mg L-1 BR. The highest chlorophyll a/b, glutathione and ascorbate peroxidase activities were recorded with 25 mg L-1 BA. Conclusively, 25 mg L-1 BA, 0.2 mg L-1 BR and 10 mg L-1 GA exhibited more promising results than other concentrations for the evaluated attributes.