Studies On Tissue Culture And Organ Formation Of Chimonanthus Praecox Link

The shrub wintersweet (Chimonanthus praecox Link) belongs to the Calycanthaceae family. It is the plant of tertiary relict species, and the plant is native to China. Wintersweet is a rare species that flowers during winter in the China, which has the high of ornamental and economic value. In this paper, we used the good variety of wintersweet as plant tissue culture material and utilized the two kinds of explants like shoot tip and axillary buds to study the technology and methods of in vitro including the time of collecting explants, type of explant, sterilization treatment, development of axillary bud and rooting.The main results are as follows:1. May is the optimum season to get explants. In this month, the contamination rate is the lowest, the maintaining green rate is the highest.2. For the different types of explants, the maintaining rate of shoot tips is higher than that of the stem segments, and the contamination rate is lower than that of the stem segments. For the different parts of branches without shoot tips, contamination rate of the upper parts is the lowest and the maintaining green rate is highest. It is shown that the shoot tips and the top of branches are suitable for tissue culture of C. praecox explants.3. The best sterilization effect was that the explants were immersed in 75% alcohol for 30 s, then were transferred into 0.1%HgCl2 for 5～7 min.4. In the same medium, both maintaining green and elongation of the upper branches were better than those of the middle and bottom parts.5. The optional medium composition for the elongation of shoot tips was like MS+6-BA2.0 mg/L+NAA0.1 mg/L+ Agar7%+Sugar3% with the rate of 8.00%. And that of axillary buds was like MS+6-BA1.0 mg/L+NAA0.2 mg/L+Agar7%+Sugar3% with the rate of 52.63%. 6. In basic medium, it was showed that the 1/2MS (1/2 of macroelements) as basic medium was the superior to MS,1/4MS due to the high frequencies of shoot elongation and maintaining green.7. In the same concentration of 6-BA and KT, the maintaining green rate, the shoot elongation rate and the callus rate were increased with the increase of NAA concentration. In the same concentration of KT and NAA, the maintaining green rate, the shoot elongation rate and the callus rate were lowered with the increase of 6-BA concentration. The optional concentrations of 6-BA and NAA were 1.0 mg/L and 0.3 mg/L, respectively.