The Studies On The Propagation Techniques And Rooting Mechanism Of Stem Cuttings Of Paeonia Lactiflora Pall

Stem cuttings propagation technology of Paeonia lactiflora were studied with'Da fugui','Qi hualushuang','Yang feichuyu'and'Tao huafeixue'by stem cuttings. Effect of different concentrations of IBA, position, leaf retention and nodes on cuttings were studied. Effect of different kinds of hormones on underground buds of cuttings were also investigated. The dynamic change of related oxidase, necessary nutriment and endogenesis hormones of Paeonia lactiflora were studied with auxin comparison experiments,the anatomical study on the occurrence of adventitious roots were carried out using paraffin section method. The thesis is to offer practice and theory for cutting rooting of Paeonia lactiflora. The main results were as the followings:The adventitious roots developed in three distinct phases i.e. induction, expression and elongation. These phases appear differences because of treating. The induction of the control is 0 to 42 days; expression 42 to 54 days; elongation 54 to 66 days. While the cuttings of pretreatment with 2 000 mgï¹’kg-1 IBA could root 18 days in advance.The percent of rooting, the number and total length of roots significantly increased with IBA pretreatment at various concentrations. The cuttings pretreated with 2 000 mgï¹’kg-1 IBA exhibited the best rooting responses and significantly improved quality of the adventitious roots. The rooting rate is up to 78.3%, obviously higher than other treatments and the average root number and total root length, compared with the other two processing, achieve the level of significant difference. The average adventitious root number is up to 52 (43 ~ 62), average root length 4.89 cm (1.37 ~ 7.06 cm). Effect of different parts of cuttings on rooting varied in varieties. The lower part of'Da fugui','Qi hualushuang','Tao huafeixue'were the best , while the upper part of'Yang feichuyu'was the best.Effect of the leaf retention left isn't a major factor in rooting of cuttings, but cuttings with two leaves are more saver than three and this should be used.Treatment with 2 mgï¹’kg-1 6-BA, NAA, GA3 can effectively promote the growth of underground buds. Of which, 2 mgï¹’kg-1 6-BA and NAA handled more underground buds, and 2 months earlier than GA3.POD and PPO activities showed the trend as slow increase and then decrease, followed by rapid increase and then decline, and decrease, then and final decrease, respectively. A similar trend existed between IBA-treated and non-IBA-treated cuttings. However, the activities of the two enzymes in IBA-treated cuttings changed more sharply and the peak in their activities appeared 18 d earlier than those of non-IBA-treated cutting. IAAO activity of non-IBA-treated cutting maintained a high level increased, then declined, and finally increased, while in IBA-treated cuttings it t declined and then increased, during rooting. The high activities of POD and PPO and low activity of IAAO appeared to be suitable indexes for rooting.Changes of soluble protein, soluble sugar and starch contents showed the trend as, decrease and then increase and final decrease, increase and then decrease and final increase, increase and then and final decrease, respectively. A similar trend existed in non-IBA-treated cuttings. The result of IBA-treated on soluble sugar and soluble protein content was not obvious, but a significant reduction in the starch content.During the rooting, changes of IAA, GA3, ZR and the ratios of IAA/ABA with IBA-treated trend all showed increase and then decrease final increase, while decrease and then increase and final decreased last increase in control. The high activities of IAA, GA3, ZR and the ratios of IAA/ABA played a dominant role to promote the adventitious roots.The anatomical observation on stem cuttings of Paeonia lactiflora showed that there were not any root anlagen before cutting. The adventitious roots mainly emerged in the cortex and origined from the parenchyma cells between xylem and pith. The adventitious root anlagen was divided and differentiated and then reached the outside of the cutting body. The roots from callus were not found. Callus formation and the emergence of adventitious roots are independent. The primary function of callus is to prevent bacteria invasion and cuttings of the effective material loss, also as a medium for nutrition and water transport.