| Teak (Tectona grandis L.f.) is one of the most valuable timber trees,which is naturallydistributed in south and south-east of Asia. It is prized for its strength, durability andappearance. Although the technology of clonal propagation in vitro through axillary budproliferation can reach the level of the Large-scale breeding,teak growers often facedifficulties in low-temperature damage, pest and disease, and so on. During the past twodecades, the shift towards teak biotechnology on teak improvement has taken place in foreigncountries, away from traditional breeding programmes. In China, the research of this field waslater than others. It was caused extensive concern in recent years. The effects of differentexplants, culture mediums, hormones and other nutrition compositions on the inducement,multiplication and differentiation of teak clones were studied in this paper, and the resultswere:1. Adopting clones of71-14,71-5,7544and7559as the gene type, the MS,1/2MS,andWPM as different basic mediums supplemented with0.5mg·L-1NAA+1mg·L-16-BArespectively, the various explants of node stem, top buds, stem (without internode) and leavesof tissue-culture container seedlings of teak, were used to study their effects of differentmediums on callus growth of teak. The results showed that the genetype of71-14,71-5werebetter than other types for callus growth of teak. MS medium was the best medium for callusgrowth. Stem (without internode) was optimum explant for callus growth2. Solid and liquid cultivation mode, light conditions and culture time were studied usingMS as basic medium and stem (without internode) as explants to explore the best cultureconditions of the callus growth. The explants cultured28days in dark condition then turned tolight condition had higher rate of the callus induction. Filter paper bridge with MS liquidmedium was better than solid culture medium. The optimal duration for callus subculture wasaround30～35days． 3. Different growth regulator levels on callus growth and callus induction was studied.During the single-factor experiment,2,4-D couldn't induct either of clones(71-14and71-5)produce callus, auxin NAA can induct callus of clone71-5,but couldn't induct callus of clone71-14. Oppositely,cytokinins6-BA can induct clone71-14produce callus, couldn't inductclone71-5. In the double factors experiment, the growth regulator combination of2mg·L-1NAA+2mg·L-16-BA was suitable for callus growth of71-14and71-5type,0.5mg·L-1NAA+1mg·L-16-BA was suitable for callus growth of71-14too.4. MS medium is also more suitable for subculture and differentiation of callus. Inducedby single hormone was hardly conducive to subculture growth and differentiation of callus.The hormone of TDZ was play an important role in callus growth and differentiation. Growthregulator combination of TDZ+IBA or TDZ+GA3was sutiable for callus subculture anddifferentiation. During experiment, we had ever been observed formations of a heart-shapedembryo on MS+0.5mg·L-1NAA medium, and a regenerated plants on MS+0.4mg·L-1TDZ+1mg·L-1IBA medium. |
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