Effect of Plant Growth Regulators on Leymus chinensis (Trin.) Tzvel. in the Xilin Gol Grassland of Inner Mongolia

Plant growth regulators (PGRs) are used to manipulate growth and development of cereal, horticultural and forage crops in most parts of the world. The present study was conducted to ascertain the effect of different PGRs at varying concentrations on growth and biomass production of Leymus chinensis (Trin.) in the Xilin Gol grasslands of Inner Mongolia, China. The PGRs which were applied exogenously included naphthalene acetic acid (NAA) at 20 mg L-1, 100 mg L-1, and 200 mg L-1; 6-benzylaminopurine (6-BA) at 5 mg L-1, 25 mg L-1, and 50 mg L-1; brassinosteroid (BR) at 0.02 mg L-1, 0.2 mg L-1, and 2 mg L-1; sodium nitrophenolate (SNP) and forchlorfenuron at SNP 10 mg + forchlorfenuron 0.5 mg L-1, SNP 50 mg + forchlorfenuron 2.5 mg L-1, and SNP 100 mg + forchlorfenuron 5 mg L-1; and gibberellic acid (GA3) at 10 mg L-1, 50 mg L-1, and 100 mg L-1. A water-sprayed plot for each replicate was included to serve as control. Results showed that PGR treatments improved growth, biomass and physiological and biochemical traits of L. chinensis plants. The maximum increase in plant height was noted in the treatment with 100 mg L-1 NAA, while 50 mg L-1 GA3 and 100 mg L-1 NAA treatments increased plant fresh and dry weights compared with their respective controls. Based on the combined interactions of morphological, physiological and biochemical traits, the results confirmed that NAA and GA3 can be used to enhance grassland productivity.