Study On Rapid Propagation Technique Of Tissue Culture In Tree Peony

About tree peony varieties with high ornamental value, the stamens and pistils highly to petalled, leading to seeds dysplasia, unable to bear seeds, while traditional ramet, grafting propagation methods has low propagation coefficient and long reproduction cycle. Using tissue culture techniques can obtain many test-tube plantlets in the short time, not only providing the genetic transformation regeneration system for breeding new tree peony varieties and ordering improvement tree peony, it also providing technological support and theoretical basis for tree peony commercialization.This study in middle-late varieties Jinge and Haihuang from the yellow tree peony as the research materials, took the main stem base bulbils as explants, studied the effects of the different collection stages on growth of tree peony tube seedlings, selected the best collection stages; this paper discussed how the different varieties and concentrations influence on tree peony tube seedlings multiplication and rooting, and obtained the optimum ratio of its proliferation and rooting hormone; analyzed how Ag NO3 influences on the proliferation and browning in the process of multiplication, measured the physiological and biochemical indexes and the relationship between the browning. The main results were as follows:(1)The bulbils of Jinge and Haihuang were selected as explants. The stages of collection bulbil explants were the 20 th day in every month from October 2013 to April 2014. The bulbils were inoculated on MS medium with 0.6 mg/L 6-BA and 0.2 mg/L NAA to study the effects of different collection stages on contamination rate, browning rate and the gown of tube seedlings. The results showed that the tree peony bulbils could be used for tissue culture from this October to next April, while the growth optimum tube seedlings were from 3-4 months tree peony bulbils. In order to break dormancy of tree peony bulbils, the treatment of cold and dark could induce the bulbils germination of tree peony in 10-11 months. So from March to April were the optimum collection stages for tissue culture of tree peony.(2)Contrasting tree peony Jinge and Haihuang on the multiplication culture of single factor test with orthogonal test results, it could be seen that a single hormone had a certain effect on proliferation of tree peony, but hormone combination use could make the proliferation coefficient of two varieties greater than using a single one. Summing up in: the best multiplication mediums of Jinge were MS + 6-BA 0.6 mg/L + NAA 0.2 mg/L + KT 0.9 mg/L + TDZ 0.06 mg/L, the best multiplication mediums of Haihuang were MS + 6-BA 0.9 mg/L + NAA 0.3 mg/L + KT 0.9 mg/L + TDZ 0.04 mg/L. Its impact on Jinge proliferation was TDZ>KT>6-BA>NAA, its impact on Haihuang proliferation was 6-BA>KT>TDZ>NAA.(3) The medium with different concentrations of AgNO3 could markedly inhibit tree peony Jinge and Haihuang browning. Adding 1 mg/L and 2-3 mg/L AgNO3 to the multiplication medium can effectively inhibited tube seedlings of Jinge and Haihuang on browning, at the same time inhibited the multiplication. With the increase of concentration of AgNO3, the browning degree of Jinge and Haihuang’s tube seedlings tended to fall before rise, the browning degree showed a significant negative correlation with SOD,POD,CAT activity, and showed a significantly positive correlation with MDA content,ethylene release quantity, PPO activity, O2.- generation rate, polyphenol content. while dealing their tube seedlings in different concentration of AgNO3 twenty days later, transferred to the optimal multiplication medium with no Ag NO3 continue to culture, not only can effectively inhibited the tube seedlings browning.but also can promoted its proliferation, the max proliferation multiple of tree peony Jinge with pretreatment of 1 mg/L AgNO3 was reach to 4.6, while the proliferation multiple of Haihuang with pretreatment of 2-3 mg/L Ag NO3 was increase a little.(4)IBA was the chief factor in rooting culture of tree peony Jinge and Haihuang. The best combination of rooting medium on tree peony Jinge was 1/2MS + IBA 4 mg/L + NAA 0.1 mg/L + AC 1 g/L, The best combination of rooting medium on tree peony Haihuang was 1/2 MS + IBA 6 mg/L + NAA 0.1 mg/L + AC 2 g/L.