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Studies On Technology About Tissue Culture Propagation Of Pinus Elliottii, P. Taeda And P. Thunbergii

Posted on:2005-05-04Degree:MasterType:Thesis
Country:ChinaCandidate:L H ZhuFull Text:PDF
GTID:2133360122996104Subject:Forest Protection
Abstract/Summary:PDF Full Text Request
Brown spot needle blight caused by Lecannosticta acicola is one of the important diseases on P. elliottii and P. taeda which are major tree species in Southern China. Silvicultural characteristics and excellent wood quality of Japanese black pine make it a favoured reforestation species in Japan, but it is susceptible to Pine wood nematode. Resistant varieties have been developed through selective breeding. But seeds supply are limited. So, it is of great value to propagate rapidly excellent breeds which can strongly resist to diseases by the means of tissue culture.Adventitious bud formation was obtained from mature embryos of P. elliottii by a short soaking of embryos in a liquid medium with high concentration of 6-BA and then transfered to 1/2 modified Gresshoff and Doy (GD) medium without hormone. Six weeks later , the highest differentiation frequency and the largest number of adventitious buds were obtained in the pretreatment with 60 mg/L 6-BA for 24h. Relatively high frequencies of large buds were obtained after a pretreatment with 30 mg/L 6-BA for 24h. On 1/2 GD medium supplemented with NAA 0.05 mg/L, adventitious shoots derived from a pretreatment with 60 mg/L 6-BA elongated more slowly and were smaller in size than those pretreated with 30 mg/L 6-BA. Roots were formed when excised shoots planted on 1/2 GD supplemented with NAA 0.05 mg/L for 4weeks, and the rooting rate was 30%.,Axillary buds were induced when the explant sources were the aseptic seedlings without roots of P. elliottii. 6-BA and KT were both effective at inducing buds formation ,but 6-BA was more potent than KT. 6-BA in combination with NAA in GD medium increased bud production comparing with the medium with cytokinin only. Basal media composition, the concentration of 6-BA and NAA and length of exposure to the cytokinin significantly influenced bud induction. The highest inducing rate of axillary buds was up to 95% on the GD medium supplemented with 4.0-5.0 mg/L6-BA and 0.05-0.1 mg/L NAA for 4-5 weeks. The addition of NAA(0.05~0.1 mg/L) or IBA (1.0 mg/L) to basal medium could greatly promote slash pine shoots elongation and growth. Reduced concentration of minerals failed to enhance shoot elongation. The shoots were propagated most rapidly when subcultured on the medium of modified GD containing 3.0 mg/L 6-BA and 0.1 mg/L NAA. Roots were formed when excised shoots were planted on modified GD 1/2 medium supplemented with 0.05 mg/LNAA or 2.0 mg/LIBA or 0.05 mg/L NAA plus 1.0 mg/L IBA and 20g/L sucrose for 30 days. The rooting rate was 53.3%, 51.6%, 64.7% respectively. The shoots elongation with different treatments influence root-induction significantly. The surviving rate was 85% when the rooting shootswere moved to the greenhouse.Axillary buds were also induced when the explant sources were the aseptic seedlings without roots of P. taeda and P. thunbergii. For bud induction, modified GD medium supplemented with 4.0-5.0 mg/L 6-BA and 0.1 mg/L NAA was best for P. thunbergii whereas a lower concentration of 6-BA(4 mg/L) and NAA (0.02 mg/L) was best for P. taeda. Addition of activated charcoal( 0.5 g/L )or NAA(0.02~0.05mg/L) to GD medium improved the growth of shoots of P. taeda but not of P. thunbergii. The most suitable medium for shoot elongation of P. thunbergii was GD without any growth regulators. Roots were formed when excised shoots were planted on modified GD 1/2 medium supplemented with 0.05 mg/L NAA , but the rooting rate of both plants were very low, only 5% ( P. thunbergii) and 12.5% ( P. taeda) respectively. Addition of activated charcoal inhibited root induction. So it would be necessary to optimize the rooting medium.
Keywords/Search Tags:P. elliottii, P. taeda, P. thunbergii, tissue culture, organogenesis, plantlet regeneration
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