香蕉高效组培快繁技术的研究

Efficient micropropagation technology for banana seedling production

【目的】改良传统的香蕉组培快繁技术提高优良种苗繁育效率。【方法】通过香蕉外植体的选取和芽诱导处理方法、芽的分化及培养、丛生芽壮芽处理、生根培养、组培苗栽培获得健康幼苗的技术过程进行优化改良。【结果】对传统吸芽处理及培养方法进行改良,使每个吸芽材料第一代出芽数量达26.4个,比传统处理方法第1代出芽数量(2.2个)提高效率12倍;生产相同数量的组培苗生产周期与传统处理法相比缩短3代。优化了不定芽分化培养基6-BA浓度和生根培养基中蔗糖的浓度,建议芽分化培养基中6-BA最适浓度为4 mg·L-1;生根培养基蔗糖最适浓度为40 g·L-1。利用椰糠、泥炭土和红壤土三种栽培基质培育组培苗,椰糠处理的幼苗叶数、株高和假茎基部直径、植株根干重和地上部干重各生长参数均显著高于泥炭土和红壤土处理,可作为重要的无土栽培介质而广泛应用。【结论】研究为提高香蕉组培快繁效率及培育健康优良种苗提供了实用指南,有利于香蕉产业的可持续发展。

[Objective] Bananas are important as a fresh fruit and staple food in the world and possess great economic value. Banana production areas and yields were around 364 thousand hectares and 13.57 million tons in China, respectively, in 2014. The banana industry links banana seedling production, pro- duction materials supply, production marketing and processing, etc., which all play an important role in farmer income and as a society stable. Healthy and strong banana seedlings from tissue culture plantlets play an important role in banana production in China. However, deficiencies exist in traditional microprop- agation methods for bananas so far, which restricts banana seedling production. The objective of this study is to build a high efficiency banana micropropagation system for the process including explant collection, initiation and proliferation culture, rooting culture and seedling hardening. [ Methods ] Conventional vari- ety Musa acuminata Cavendish ＇Baxi＇was used as the plant material. Healthy and strong banana suckers were collected as explants. Suckers were cleaned and cut short to a 2 cruX2 cm size, and were then disin- fected with 75% ethanol and 0.1% HgC12. Using the improved sucker treatment method T1, the sucker sheathing leaves were removed layer by layer, and then cultured in the induction medium. In the tradition- al method （T2）, the cleaned sucker pseudostem was directly cut into two bases and put in the induction medium. Inducted buds were observed for two generations. In the proliferation culture, different concentra- tions of 6-BA （ B 1 ： 2.0 mg; B2 ： 3.0 mg; B3 ： 4.0 mg; B4 ： 5.0 mg; B5 ： 6.0 mg） were used in the proliferation medium, and subcultured for two generations. The proliferated buds were then counted and growth param- eters were measured. In the rooting system, different sugar concentrations of S 1 ： 25 g·L-1 ;S2 ： 30 g·L-1 ; S3：40g·L-1; S4：45 g·L-1 were used in the rooting medium, and cultured for 40 days, then the growth pa- rameters of the seedling height, roots number and pseudostem diameter were measured, In the seedling hardening study, three culture media, coconut coir, peat soil and red loam were used, then cultured for two months and then detected the parameters of plant height, leaf number, relative chlorophyll and plant bio- mass, etc. [Results] With the improved sucker treatment method T1, 26.4 and 59.8 buds appeared in the 1st and 2nd generation, respectively; while only 2.2 and 6.6 buds appeared with the traditional method T2. The new sucker treatment method T1 improved initiation efficiency 12 times more than the traditional method with 26.4 buds grown in the 1st generation. For the proliferation culture, increased 6-BA concen- tration showed more proliferated buds. The increase indexes were 2.73 and 2.42 in the 1st and 2nd genera- tion, respectively for the B5 treatment; while 2.37 and 2.31 for the B3 treatment. Significant larger number of buds were grown in B3 than B1 and B2 treatments, and no significant differences between the B3 and B4 treatments. In the rooting study, with increasing sucrose concentration, longer and more roots were grown, while no significant differences were noted in the $3 and $4 treatments. In the seedling hardening study, with coconut coir treatment, the growth parameters of the leaf numbers, plant height, shoot and root dry matter were higher than those of the other two treatments, which showed the lowest values in red loam. [Conclusion]The improved sucker treatment method T1 improved initiation efficiency, and shortened 3 generations with the same number of buds compared to the traditional method T2. The higher efficacy of method T2 saved suckers and decreased the off-type rate. For the proliferation culture, the 6-BA concen- tration was optimized as 4 mg· L-1 （B4）, while the sucrose concentration was screened as 40 g· L-1 （S3） in the rooting medium. Coconut coir treatment showed the greatest potential in seedling hardening, and pro- motion of coconut coir also benefited healthy banana seedling culture production.