Study on Rooting Characteristics of Litsea coreana Levl var. sinensis Cuttings

To investigate the effects of lignification degree and hormone concentration on the rooting of Litsea coreana Levl var. sinensis softwood cuttings, a two-factor completely randomized block design was employed to analyze the influences of cutting lignification degree and IBA·NAA concentration on root morphology and physiological metabolism. Additionally, anatomical studies were conducted to clarify the rooting characteristics of L. coreana var. sinensis cuttings. The results showed that the rooting rate of cuttings with a low degree of lignification was higher than that of semi-lignified cuttings. IBA·NAA significantly improved the rooting rate and root morphological indices of the cuttings. The optimal treatment combination was 100 mg/L IBA·NAA applied to low-lignification cuttings, which achieved an average rooting rate of 90% after 120 days of cultivation. L. coreana var. sinensis exhibits an induced rooting type, and the rooting pattern can be classified into Cortex rooting type and mixed rooting type. Root primordia mainly originate from the pericycle, with partial origins from callus, phloem, parenchyma cells, and other tissues. IBA·NAA helps to increase the contents of soluble sugars and proteins in cuttings, enhance the activities of indoleacetic acid oxidase (IAAO), peroxidase (POD), and polyphenol oxidase (PPO), stimulate the increase in auxin and cytokinin levels, and reduce the total phenol content, thereby maintaining the physiological activity of the cuttings.