Studies On Soft Cutting Propagation Technique And Rooting Mechanism Of Taxodium Mucronatum×Cryptomeria Fortunei

Taxodium mucronatum×Cryptomeria fortunei, which belongs to Taxodium Rich genus of Taxodiaceae family, it's excellent for the production of timber, shelter belt and ornamental purpose with many virtues, just like rapid growth, wind resistance, salinity tolerance, water tolerance and so on. The cutting propagation technique and rooting mechanism of Taxodium mucronatum×Cryptomeria fortunei was studied, the main results were as follows.1. studied on cutting propagationThe rooting rate was the highest when dip in the mixture of 1000mg·L^-1 IBA and 1000mg·L^-1 NAA twenty seconds, rooting percentage reached as high as 86.7%. The index of root system was the highest when dip in the mixture of 1000mg·L^-1 IBA and 1000mg·L^-1 NAA five seconds. Cuttings come from middle to upper shoots(0.40～0.45cm in diameter) would be benefit for the propagation.2. Cytology during adventitious rooting formationIncubate root primordiums have not been found in cuttings, adventitions roots belong to the type of induced root primordiums. The induced root primordiums initialed from the pith radial march with the vascular cambium cells, the callus could not form adventitious root primordium .3. Studied on the physiology during adventitious root formationDuring adventitious root formation, most of the content of nutritive substance declined with the emergence of cullusing and rooting.The higher levels of IAA was demanded for root primordium inducement and morphogenesis, GA₃ and IAA cooperated with root primordium inducement and morphogenesis. The content of ABA and ZR on disposal cuttings is more than control cuttings during root primordium morphogenesis. The high ratio of IAA/ABA and IAA/ZR conducive to the inducement of adventitious roots in some extent.The activities of POD increased gradually during the root primordium inducement and adventitious root morphogenesis, and declined gradually during the root primordium initiation. The activity of PPO increased gradually during the root primordium inducement and morphogenesis. With the elongation of adventitious roots, the activity of PPO declined gradually. Later in the rooting, the content of MDA increased rapidly, much higher than the disposal cuttings.