Effect of epi-brassinosteroid and Gibberellin on seed germination and seedling growth of Leymus chinensis

Leymus chinensis is one of the dominant species on the northern grassland of China. It has both high economic and high ecological value. However, the poor germination ability and deep dormancy of seed limit the grass production and utilization of L.chinensis. Plant hormone treatment is one of the efficient pathways to resolve these problems. Epi-brassinosteroid (EBR), one of the artificial synthesized materials with the similar biological function with BLs, has been proven to improve seed germination and seedling growth efficiently under both normal and stress condition. To our knowledge, few studies have been published to report the effect of EBR on seed germination and seedling growth of L.chinensis. Hence,this research is conducted to address two key questions: 1) Is there any positive effect of EBR on seed germination and seedling growth of L.chinensis? 2) Is there any combined effect when two hormones are used together? The positive effect of EBR treatment on the seed germination and root growth are observed. The germination rate of EBR-treated seeds increases 2~4 times than that of the seeds been treated by water. Moreover, the root length of seedling developed by EBR treated seeds increases by 35%~40% compared with the control. Both the germination rate and seedling growth vary significantly (P0.05) with the concentration of EBR being used for the treatment. Compared with the treatment by the single hormone as EBR or Gibberellin(GA3), the germination rate of seeds been treated by two hormones increase by 20%~30%, the leaf and root length of seedling developed from the seeds treated by two hormones increase by 49.14% and 51.34%, respectively. EBR does have positive effect on the seed germination and seedling growth of of L.chinensis. And the two-hormone treatment is better than that of single-hormone. The optimized combination of two hormones are EBR 0.10 μg·g-1+GA3 200 μg·g-1 and EBR 0.01 μg·g-1+GA3 200 μg·g-1, which show the highest of seed germination rate and the best performance of seedling growth of L.chinensis.