Effect of Cuttings with Different Lignin Contents on Cutting Rooting of Tetraploid Robinia pseudoacacia

We measured the lignin content and cross-sectional shear strength of 1-year-old softwood cuttings of Tetraploid Robinia pseudoacacia in order to investigate the relationship between lignin content and cross-sectional shear force,and the effects of different lignin contents in cuttings on rooting.The results showed:(1)A positive correlation was found between the lignin content of cuttings and their cross-sectional shear force,thus,the lignin content might be inferred based on its shear force.(2)The lignin content of cuttings between POD and PPO enzyme activity were significantly positive correlation(correlation coefficient of POD and PPO were 0.98 and 0.92,respectively);and the lignin content of cuttings with ABA hormone content significantly positive correlation(correlation coefficient was 0.97);however,the lignin content of cuttings with IAA and IBA on significantly positive correlation;according to the influence of POD enzyme activity of roots can speculate that the lignin content has a certain effect on rooting.(3)The lignin contentof cuttings and POD enzyme activity was significantly positive correlation(correlation coefficient of 0.98.According to the influence of POD enzyme activity of roots can speculate that the lignin content has a certain effect on rooting.(4)The optimum rooting ability appeared in cuttings containing 19.47% lignin content,and their shear force ranged from 40 to 50kg.This study will provide a theoretical basis for selecting appropriate cuttings of Tetraploid R.pseudoacaciain rooting experiment.