A Comparatively Study On The Tissure Culture Characteristics Of Populus Tomentosa Carr.Clones

Populus tomentosa is one of the most important hardwood timber trees in China. Its some aspects are very outstanding in popular such as fast-growing, wood quality, resistance to adversity envirenment conditions and so on. There is a long cultivate history in Huanghe River basin and the Plain of North China for this specice. Owing to its large genetic variation existing in nature and artifical populations, a great deal of excellent clones have been selected to establish fast-growing stands. However wood cuttings are difficult to root or the rooting freauency may be rather low. So their development is limited. In such case tissue culture techniques may be exploited as means of accomplishing clonal propagation. It could not only get chracteritics identical populations, but accelerate excellent clones development and use.Five excellent clones of P. tomentosa were used in this study. Tissue of terminal bud was cultured under aseptic conditiond. Sterile shoots and its leaf were used as explant to induce bud differentiation and growth, as well as rooting in different medium. The potential of plantlet regeneration was compared with different clones. The results are as follows:1. All five clones of P. tomentosa could obtain regeneration plantlets by organogenesis in vitro. However there is greatly difference in demand in mediunu hormone and concentration for clones. So the growth and differentiation response is not only controlled by cultural environment, but is also dependent upon the genotype.2. Inducing rate of two clones are higher on MS than WPM, that of one clone is as high as on two mediums, that of one clone is lower on MS than on WPM. In general MS is more adequate for mass clone. Including BA0.2mg/l on two medium.3. Axillary bud of five clones were cultured on MS with different combinations of concentration of hormones. The results indicate that different clones have different the most adequate combination of hormones. No. 1 suits to BA0.3mg/l + NAA0.05mg/l ; No. 2 BA0.3mg/l +NAA0.01mg/l ; No.3 BA0.5mg/l+NAA0.01mg/l ; No. 4 BA0.5mg/l + NAA0.01mg/1 ; No. 5 BA0.7mg/l + NAA0.05mg/l ; Among five clones No. 4 is best to multiplication and growth than the rest, Number of shoots reachs 17 .3. Leaves were cultured on MS with different concentration of BA and NAA as explant. Different clones leaf suit to different concentration of hormones. Inducing rate of No. 1 is the higest on BA0.3mg/l +NAA0.5mg/l , attaines 91.67% ; No. 2 on BA0.3mgA + NAA0.5mg/l, inducing rate 100%; No.3 on BAO.Smg/1 +NAA0.05mg/l . inducing rate100% ; No. 4 on BA0.3mg/l + NAA0.5mg/l or BA0.5mg/l+NAA0.5mg/l , inducing rate 100%. Mediums for Multiplication and growth of adventitious shoots as follows: No. 1 is BA0.5mg/l+NAA0.03mg/l ; No. 2 and No. 4 are BA0.3mg/l+NAA0.01mg/l; No. 3 is BA0.3mg/l+NAA0.03mg/l.4. GAs can promote growth of shoots. GAs can not only promote growth of shoot but also promote multiplcation of shoot when it is used with BA and NAA. The best concentration of GAa is 2.0mg/ml.5. Root were induced on 1/2MS by supplementing of different hormones. The best combination of hormones for No.l No.2 and No.3 are NAA0.01mg/l+ IBA0.2mg/l, No.4 is IBA0.4mg/l, No. 5 is IBA0.2mg/l. Rooting rate is 96.67%> 93.33%, 56.67% 56.67% 93.33% respectively..