Propagation Techniques And Rooting Mechanism Of Chukrasia Tabular Is Softwood Cuttings

Chukrasia tabularis,belongs to Chukrasia A.Juss genus of Meliaceae family,is a large evergreen to semi-deciduous tree,which has straight trunk,broad crown,delicate leaves,fragrant flowers,and excellent wood properties.It is a landscape greening and preciously native specie in tropical and southern subtropical zones of China.In order to broaden the breeding mode conservation and use C.tabularis resources to adapt to its development,systematically studied the propagation technology of C.tabularis softwood cuttings from seven aspects,including culture substrate,exogenous hormones,cutting length,styles of keeping leaves,the cuttings parts,cutting seasons and water-cultured,and carried out test study in the process of cuttings rooting about endogenous hormones,the dynamic changes of nutrient contents and oxidase activities in different organ parts of cuttings,to search for its rooting mechanism.The specific research results are as follows:(1)The mixed substrate of peat soil+vermiculite with the volume ratio of 1:1 was the best;Hormone orthogonal test results showed that,hormone species had the most influence on rooting of C.tabularis cuttings,the cutting rooting effect of ABT1 was the best,followed by IBA.and NAA was worst;The optimal hormone treatment was with ABT]of 1000 mg·L-1 for 10s.The rooting of C.tabularis cuttings was significantly affected by lengths,parts and keeping leaf styles of cuttings.The better rooting cuttings were selected from the bottom part of the semi-lignified branches with three pinnate leaves and with 10?12 cm lengths of cuttings.The rooting properties of cuttings were significantly affected by the treatments with different concentrations of I BA and ABT1 solution,and all rooting traits treated with ABT1 were significantly better than those treated with I BA.With the increase of ABT1 concentration,the rooting effect of cuttings first increased and then decreased,and the best rooting effect was with ABT1 500 mg·L-1.Cuttings in March was the best based on the experiment of different cutting seasons,with rooting rate was 95.83%.Chukrasia tabularis cuttings can be progaged by water-culture method,rooting rates and quantities with ABT1 150 mg·L-1and 300 mg·L-1 treatments wre over 10%and 2 roots in the experiment.(2)The results proved that the rooting types of C.tabularis softwood cuttings were mostly originated from cortex of the bottom section,a small number of cuttings were callus rooting type and intermediate rooting type.The rooting process could be divided into three periods:Induction period of root primordium germination in lenticels(0?20 days),Stage of adventitious root expression(20?40 days)and Elongation of adventitious roots during development(after 40 days).(3)During the rooting process of C.tabularis cuttings,to some extent,application of exogenous hormone IBA could increase the content of endogenous hormone IAA.GA.ZR and the ratio of IAA/ABA,IAA/ZR,and reduced the content of ABA.High concentration of IAA and stable low concentration of ZR were beneficial to occurrence of adventitious roots.ABA with low concentration was beneficial to formation and elongation of adventitious roots;At the same time,lower IAA and GA levels were beneficial to elongation and growth of cuttings root system.The higher IAA/ZR and IAA/ABA ratios were beneficial to rooting of C.tabularis softwood cuttings.(4)Exogenous hormone treatment accelerated metabolism proceed of nutrients in C.tabularis cuttings and was beneficial to rooting.The contents of soluble sugar and starch were significantly hisher than that of soluble protein,variation range was also larger than soluble protein content,which was more closely related to cuttings rooting.(5)There was a close relationship between the activity of oxidase and rooting of C.tabularis cuttings.The treatment with exogenous hormone ABT1 could increase POD.PPO activities and decreased IAAO activity.POD activity was relatively higher during the period of root elongation and development,while low in the period of root primordium induction activity.PPO activity was higher in root emergence period.The change track of IAAO and IAA activity basically showed a reciprocal relationship.(6)There were some substances in C.tabularis cuttings which had different effects on the germination of white rapeseed,the contents of the substances in different parts of branches were different but it is difficult to determine the effect on cuttings rooting.