Callus and Adventitious Buds Formation from Stem Explants of Balsam Pear （Momordica charantia L.）

The effects of sterilization pretreatment, sampling time and growth regulators on callus formation, explant contamination and adventitious bud induction from stems of balsam pear （Momordica charantia L.） were investigated. Sterilized for 6 rain with 0.1% （w/v） mercuric chloride solution is an essential sterilization method for stems. June and July proved to be better for material taking, followed by May. The callus formation rate of balsam pears reached the highest when medium added with IBA 1.0mg/L and BA 2.0 mg/L, while the optimum medium for adventitious bud induction was MS added with IBA 0.5mg/L and BA 4.0 mg/L. And it will provide theoretical and technical basis for rapid propagation and breeding.

Direct Adventitious Bud Induction and Plant Regeneration of Rosa hybrida Samantha

Effect of explant, site of leaflet, induction period in the dark and combinations of plant growth regulators on direct adventitious bud induction and plant regeneration of Rosa hybrida Samantha was investigated. The results showed that after an induction period of 8 d on MS medium with 1.5 mg L-1 TDZ and 0.05 mg L-1 NAA in the dark and a subculture on MS medium with 0.5 mg L-1 BA and 0.01 mg L-1 NAA under light, the best plant regeneration was obtained and the regeneration frequencies of leaflets and petioles were 51.8 and 10% respectively. There was no significant difference in regeneration ability between leaflets at different sites of the compound leaves, longer time of induction in the dark or high concentration of auxin would cause callus formation, which was disadvantageous for shoot regeneration, and the regeneration frequency was significantly reduced. This regeneration system could be applied for genetic transformation of this cultivar in the future.

Inducing Adventitious Buds from Tomato Callus and Their Rooting

[ Objective] The aim was to establish efficient regeneration system of tomato so as to study the genetic transformation of chloroplast in tomato. [ Meth- od] The tomato seeds were sterilized and cultured into plantlets. Then, the leaves were cut from plantlets and placed in the MS with 3.0 mg/L 6-BA ＋ 0.3 mg/L IAA to induce callus. Finally, the effect of different hormones and concentrations on induction of adventitious buds from tomato callus and rooting was compared. [Result] The best medium for the induction of differentiation of adventitious buds from callus was： MS ＋ 2.0 mg/L 6-BA ＋ 0.3 mg/L sugar. The best medium for rooting was： 1/2MS ＋ 1.0 mg/L IAA. [ Conclusion] Appropriate sdection of hormone concentrations is the key to establish efficient regeneration system for tomato.

Effects of Different Hormone Proportions on Differentiation and Regeneration of Prtmus avium L. Adventitious Buds

In order to screen the appropriate culture condition for the differentiation and regeneration of Prtmus avium L. adventitious buds, in this study, the effect of different hormone proportions on differentiation and regeneration of shoot tip explants were investigated using Gisela No. 5 and Gisela No. 6 as experimental materi- als. The results showed that, different hormone proportions had extremely significant effects （ P 〈0.01 ） on the differentiation rate of P. avium adventitious buds; the appropriate hormone proportions for Gisela No. 5 and Gisela No. 6 to induce dedifferentiation of adventitious buds were 6-BA 3.0 mg/L ＋ IBA 0.5 mg/L ＋ KT O. 1 mg/L and 6-BA 1.0 mg/L ＋ IBA 0.5 mg/L ＋ KT 0.2 rag/L, respectively. In addition, different hormone proportions had extremely significant effects （P 〈 0.01 ） on the regeneration coefficient and regeneration rate of P. avium adventitious buds; with the hormone proportion of 6-BA 1.0 mg/L ＋ IBA 1.0 mg/L ＋ KT 0.3mg/L, the number of regenerated adventitious buds reached the maximum for both varieties.

Micropropagation of Carob(Ceratonia siliqua L.)through Adventitious Buds of Immature Embryonic Cotyledons

Adventitious budding from embryonic cotyledons of immature seeds of carob was obtained. The combination of BAP (4.44 μM) and NAA (1.5 μM) furthered the neoformation of adventitious buds. These latter were multiplied on MS medium added with BAP (2.22 μM). Stems and leaves growing were improved by adding 2.02 μM GA3. Elongation was favored by 0.5 μM NAA. 70% of rooting was obtained with 10 μM IBA.

Regenerating Plants from Cryopreserved Adventitious Buds of Haploids in Rice

A large number of adventitious buds were induced from in vitro cultured young inflorescences of haploids of rice.Having been subcultured on solidified subculture media at 26 ℃ for 7 days ,the adventitious buds were loaded into 1.8 mL plastic cryotubes with cryoprotectant and kept on ice for 45 60 min.After cooled at a rate of 1.0℃/min down to -40℃,the samples were kept in liquid nitrogen.The adventitious buds which have been cryopreserved for about 30 days were thawed rapidly in 38 40℃water and then plated on solidified MS medium containing 3 % sucrose,0.5 mg/L NAA and 2.0 mg/L kinetin.After plated, 23% 32 % of adventitious buds resumed growth and 15% 22 % regenerated plantlets.The results of this work indicated that the adventitious buds derived from in vitro cultured young inflorescences is a critical factor for the success and subculturing adventitious buds on MS medium containing 3% sucrose and 4% sorbitol or 20% potato extract is essential to the procedure.The effective cryoprotectant is 10 % DMSO(dimethyl sulfoximide)+0.5 mol/L sorbitol.

A New Micropropagation Technology of Tilia amurensis:In VitroMicropropagation of Mature Zygotic Embryos and the Establishment of a PlantRegeneration System

Tilia amurensis is an economically valuable broadleaf tree species in Northeast China.The production of highqualityT.amurensis varieties at commercial scales has been greatly limited by the low germination rates.Thereis thus a pressing need to develop an organogenesis protocol for in vitro propagation of T.amurensis to alleviate ashortage of high-quality T.amurensis seedlings.Here,we established a rapid in vitro propagation system forT.amurensis from mature zygotic embryos and analyzed the effects of plant growth regulators and culture mediain different stages.We found that Woody plant medium(WPM)was the optimal primary culture medium formature zygotic embryos.The highest callus induction percentage(68.76%)and number of axillary buds induced(3.2)were obtained in WPM+0.89μmol/L 6-benzyladenine(6-BA)+0.46μmol/L kinetin(KT)+0.25μmol/Lindole-3-butryic acid(IBA)+1.44μmol/L gibberellin A_(3)(GA_(3)).The multiple shoot bud development achievedthe highest percentage(83.32%)in the Murashige and Skoog(MS)+2.22μmol/L 6-BA+0.25μmol/L IBA+1.44μmol/L GA_(3).The rooting percentage(96.70%)was highest in 1/2 MS medium+1.48μmol/L IBA.Thesurvival percentage of transplanting plantlets was 82.22%in soil:vermiculite:perlite(5:3:1).Our study is the firstto establish an effective organogenesis protocol for T.amurensis using mature zygotic embryos.

Different Explants of Lilium lancifolium Have Different Potential to Differentiate and Regenerate in Tissue Culture

[Objective] The aim was to investigate differences in differentiation and regeneration of the explants from different parts of Lilium lancifolium（Yixing Lily） in tissue culture.[Method] The different parts of scale,leaf and root of Yixing Lily were cultured as explants on MS basic medium supplemented with different concentrations of plant growth regulators,so as to compare their capacity to differentiate and regenerate.[Result] The explants had different potential to differentiate（scale root leaf）.The capacity of different scale parts to differentiate was the lower part middle partupper part;the capacity of different leaf parts to differentiate was the leaf base middle part leaf tip;the capacity of different root parts to differentiate was the root base root tip middle part.[Conclusion] Tissue culture could be well applied in propagation of Yixing Lily.

Establishment of Rapid Propagation Technique for Cotyledon of Solanum torvum

[Objective] To research the mass propagation system for cotyledon of Solanum torvum. [Methods] With cotyledon of S. torvum as the research object, ef- fects of hormone combination on callus induction and adventitious buds differentia- tion of S. torvum were researched. [Results] With cotyledon of S. torvum as the ex- plants, the optimal culture medium for callus induction and adventitious buds differ- entiation was MS＋2.0 mg/L 6-BA＋0.3 mg/L NAA. The induction rates of callus and adventitious bud reached 100% and 85%, respectively. The number of average buds was 6. The optimal culture medium for the induction of adventitious roots was MS＋ 0.3 mg/L IAA. The rooting rate reached 100% and the number of average roots was 9. [Conclusions] One-step induction of callus and adventitious buds simplified the mass propagation system, and enhanced the test test efficiency.s

Application of Plant Growth Regulator TDZ in Strawberry Anther Culture

[Objective] The aim was to investigate the application of plant growth regulator thidiazuron（TDZ）in strawberry anther culture.[Method]Different combinations of TDZ and naphthalene acetic acid（NAA）auxine with different concentrations were used for induction culture,and then its effect on callus induction and plant regeneration were observed.[Result] The combination of 1.0 mg/L TDZ＋0.5 mg/LNAA was effective to accelerating the differentiation and regeneration of strawberries,and the differentiation ratio was as high as 75%.However,TDZ showed insignificant effect on strawberries anther induction.[Conclusion]This research had provided reference for large-scale production of strawberry through anther culture.

Optimization of the uidA Gene Transfer of Rosa hybrida via Agrobacterium tumefaciens: an Assessment of Factors Influencing the Efficiency of Gene Transfer

To develop a transformation protocol of Rosa hybrida Samantha via Agrobacterium tumefaciens, the authors examined the effect of different factors on T-DNA transfer by measuring transient expression levels of an intron-containing -glucuronidase gene. The results indicate that explant, light condition, salt concentration and acetosyringone (AS) concentration in co-culture medium are the most important factors, and factors like co-culture temperature, co-culture period and bacteria density have a strong effect on the growth of bacteria and then T-DNA transfer. Optimized co-cultivation was performed by inoculation of embryogenic callus with bacteria at a density of OD600= 0.50.8 for 20 min and co-culture in darkness under 23 C on medium with 1/2 MS salts and 300 mol稬1 AS for 3 d.

In vitro Regeneration of First-generation Inbred Progenies of Cucurbita pepo L. Double Haploids

Using seeds of inbred progenies of Cucurbita pepo L. DH12-11409 double haplolds as experimental materials, the effects of different hormone combinations, explant types and seedling ages on adventitious bud regeneration and rooting of C. pepo L. were investigated. According to the results, inoculating cotyledonary nodes of yellow-green cotyledons from 5-d-old C. pepo L. double haploids to MS ＋ 30 g/L Suc ＋ 8 g/L Agar ＋ 2.0 mg/L 6-BA ＋ 0.1 mg/L NAA led to the best results with the induction frequency of 90.0% and differentiation coefficient of 8.5. MS medium with addition of 0.05 or 0.1 mg/L NAA led to the highest rooting rate. Regenerated seedlings with 5 - 6 true leaves exhibited the highest survival rate of 90.0%, which was the optimal period for domestication and transplanting of regenerated seedlings. This study laid a solid foundation for high-efficiency utilization of heterosis of C. pepo L.

The Efficient Tissue Culture System of Orostachys fimbriata

This study aimed to investigate the tissue culture and rapid propagation techniques of Orostachys fimbriata, a medicinal and ornamental herbaceous perennial herb belonging to the family Crassulaceae. The leaves of O. fimbriata were used as explants to investigate the effects of plant growth regulators such as thidiazuron (TDZ), 6-benzylamino purine (6-BA) and 1-naphthaleneacetic acid (NAA), on the induction of callus, differentiation of adventitious buds and rooting of shoots. Our results showed that optimum callus induction medium was MS medium supplemented with 0.5 mg·L-1 TDZ and 0.2 mg·L-1 NAA. 1.5 mg·L-1 6-BA and 0.2 mg·L-1 NAA was the optimum hormone combination for differentiation of adventitious buds. And 0.1 mg·L-1 NAA could efficiently promote rooting. The survival rate of transplants reached about 90%. In this study, using leaves of O. fimbriata as explants, high efficient tissue culture and regeneration system of O. fimbriata were established, and the period from leave to transplant plantlet was about 3 months. The presently developed protocol could be used for large scale clonal propagation and germplasm conservation of O. fimbriata. The efficient tissue culture system of O. fimbriata would provide technical support for its utilization.

REGULATION OF PHYTOHORMONS ON THE REGENERATION OF SHOOT-TIPS OF ANTIRRHINUM MAJUS INTO PLANTLET IN VITRO

Tissue culture of Antirrhium majus was experimented by using the tip of shoots as the explants, and comparing the effects of NAA, IAA and 2, 4-D on the formation of adventitious buds. The results indicated that the effect of NAA was the best for the formation of adventitious buds, 5.0, 7.0, 9.0, 11.0, 13.0 mg/L BA combinatcd with 0.1, 0.5, 1.0, 1.5, 2.0 mg/L NAA respectively. The results show that combinations of the concentrations of BA 7.0-9.0 mg/L and NAA 0.1-0.5 mg/L were advantageous to the regeneration of buds and NAA was very important for callus growth.

High-frequency Induction of Adventitious Shoots from Leaves of Robinia pseudoacacia by Thidiazuron

The effectiveness of thidiazuron（TDZ）on adventitious bud and shoot formation from leaves of Robinia pseudoacacia was tested in combination with naphthaleneacetic acid （NAA）or 2,4-dichiorophenoxyacetic acid （2,4-D）,With the increasing of TDZ level,the induction rate of adventitious buds appeared an increasing trend and the highest rate was obtained by the combination of 2mg/L TDZ whth 0.1mg/L NAA.The excessive level of TDZ could induce useless cellae and easily produce hyperhydricity.Inhibition of shoot elongation by TDZ was overcome through transferring shoot cultures to a shoot proliferation medium lacking TDZ orcontaining NAA,benzyladenine （BA）and TDZ.Indole-3-butyric acid （IBA）was used to stimulate the rooting in vitro .Based on the number and length of rooting ,the treatment with 0.5mg/L IBA was the best.