| We investigated the in vitro callus induction and proliferation of tree peony (Paeonia suffruticosa) by the facts as explants types, basic medium types, plant growth regulator types and concentrations, light quality ratios and light intensity, five cultivars (’Luo Yang Hhong’,’Wu Long Peng Sheng’,’Feng Dan Bai’,’Hu Hong’ and ’Shan Hu Tai’) as the material, to select a suitable medium formula, light quality ratios of light-emitting diodes (LED) and cold cathode fluorescent lamps (CCFL) and LED illuminations for building a effective and stable callus induction system of tree peony. And we also studied the effect of basic medium types, plant growth regulator types and concentrations, culture methods on the adventitious buds and somatic embryos induction from callus in order to building a effective and stable somatic embryos induction system of tree peony. Results are as follows:1. By studying the effect of hormones types and concentrations on callus induction of Paeonia suffruticosa,’Luo Yang Hong’, we found that the induction rates of callus from the parts of petiole were higher than leaf and stem’s in five explants types; the induction rates of callus from the part neared the stem was better than other petiole parts which neared leaf or middle side. Callus of tree peony could be obtained by only using 6-BA, and effect of callus induction of 6-BA with 2,4-D treatments were better than 6-BA with NAA treatments by comprehensive considering with callus induction rate and explants browning rate.6-BA 1.0 mg·L-1 add 2,4-D 1.0 mg·L-1 treatment was the better one for Paeonia suffruticosa ’Luo Yang Hong’ petiole to induce callus among the 6-BA with 2,4-D treatments, and NAA1.0 mg·L-1 add 6-BA 1.0 mg·L-1 treatment was best one for callus proliferation among the NAA with 6-BA treatments.2. It had a significant difference on the rate of callus induction by Paeonia suffruticosa varieties. The callus induction rates from the petiole parts and leaf of Paeonia suffruticosa ’Hu Hong’ were higher than Paeonia suffruticosa "Wu Long Peng Sheng’ and ’Luo Yang Hong’,’Luo Yang Hong’ was the worst. Callus induction rates from petiole of’Wu Long Peng Sheng’,’Luo Yang Hong’ and ’Hu Hong’ were all higher than leaf’s, and it had a decreased tendency of callus induction rates from the petiole part neared stem, middle side to the part neared leaf, and the induction rate of petiole callus from ’Hong Hu’ was highest (62.2%).3. Effect of callus induction from the middle part of the petiole was the best one among the four explants types in different LED light quality conditions, and effect of callus induction under 75% R add 25% B treatment was also the best one among the seven light quality ratios. The rate of callus induction under dark treatment and control (PGF) treatments were less than others. In the proliferation, the increasing weight and increasing rate of Paeonia suffruticosa ’Feng Dan Bai’ callus in the 70% R add 30% B treatment was the highest under LED conditions, and that of Paeonia suffruticosa ’Shan Hu Tai’ in the 60% R add 40% B treatment was also the best one under CCFL conditions. When the illumination in a certain range from 30μmol·s-1·m-2 to 80μmol·s-1·m-2, it had a the overall increased first and then decreased trend of the increasing weight and increasing rate of Paeonia suffruticosa ’Feng Dan Bai’ callus with increasing illumination, and that of Paeonia suffruticosa ’Feng Dan Bai’ callus under the conditions of 60μmol·s-1·m-2 treatment were significantly higher than others; however, the higher illumination was not conducive to the callus proliferation.4. Effect of the adventitious buds induction from Paeonia suffruticosa ’Feng Dan Bai’ callus was better than that of Paeonia suffruticosa ’Wu Long Peng Sheng’ callus with two culture methods that was solid culture method or liquid culture method. And effect of different treatments on the adventitious buds induction from Paeonia suffruticosa callus based on 1/2 MS basic medium was better than that of MS medium under solid culture method, meanwhile, the induction rate of adventitious buds from Paeonia suffruticosa ’Wu Long Peng Sheng’ was best one with MS add Ca2+(WPM) add NAA 0.5 mg·L-1 add 6-BA 1.5 mg·L-1 treatment, and that of Paeonia suffruticosa ’Feng Dan Bai’ was the treatment with 1/2MS add Ca2+(WPM) add NAA 0.1 mg·L add 6-BA 0.5 mg·L-1 by considering the adventitious buds induction rate, glass-like rate and browning rate of callus. The treatment with 1/2MS add Ca2+(WPM) add NAA 0.5 mg·L-1 add 6-BA1.0 mg·L-1 was the best one for Paeonia suffruticosa ’Wu Long Peng Sheng’ callus to induce adventitious buds, and the best one for Paeonia suffruticosa ’Feng Dan Bai’ was the treatment with 1/2MS add Ca2+(WPM) add NAA 0.1 mg·L-1 add 6-BA 0.3 mg·L-1 under liquid culture method. It was a certainly correlation among the rate of glass-like and browning on callus and the adventitious buds induction rate.5. Effect of the somatic embryos induction from Paeonia suffruticosa ’Feng Dan Bai’ callus was better than that of Paeonia suffruticosa ’Wu Long Peng Sheng’ callus with two culture methods that was solid culture method or liquid culture method. And under solid culture method, WPM medium was the best one for Paeonia suffruticosa ’Wu Long Peng Sheng’ callus to induce somatic embryos, followed by 1/2MS medium, and then was MS medium. The hormone of 6-BA was the best one for Paeonia suffruticosa ’Wu Long Peng Sheng’ callus to induce somatic embryos, followed by TDZ, and then was KT. Effect of induction medium of somatic embryos for Paeonia suffruticosa ’Feng Dan Bai’ was 1/2MS medium, WPM medium and MS medium, and effect of hormone on Paeonia suffruticosa ’Feng Dan Bai’ somatic embryos induction was TDZ,6-BA and KT. And considering the somatic embryos induction rate and callus browning rate, the induction rate of somatic embryos from Paeonia suffruticosa ’Wu Long Peng Sheng’ was best one with WPM add 6-BA 1.5 mg·L-1 treatment, and that of Paeonia suffruticosa ’Feng Dan Bai’ was the treatment withl/2MS add Ca2+(WPM) add TDZ 0.5 mg·L-1 under solid culture method. The treatment with 1/2MS add Ca2+(WPM) add TDZ 0.1 mg·L-1 was the best one for Paeonia suffruticosa ’Wu Long Peng Sheng’ callus to induce somatic embryos, and the best one for Paeonia suffruticosa ’Feng Dan Bai’ was the treatment with 1/2MS add Ca2+(WPM) add 6-BA 1.5 mg·L-1 under liquid culture method. Meanwhile, It also had a certainly correlation among the callus browning rate and the induction rate of globular embryo and cotyledon embryo. |
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