【作者】 崔瑾；

【导师】 李式军； 吴琴生；

【作者基本信息】 南京农业大学 ， 蔬菜学， 2002， 博士

【摘要】 芋（Colocasia esculenta L.Schott），是一种重要的蔬菜和药用植物，在我国具有悠久的栽培历史。芋还是迄今发现的耐盐性最强的蔬菜作物之一，长期栽培可以降低土壤的盐渍化程度，对滩涂的开发和利用具有较大的应用价值。 在传统栽培中，芋一般采用球茎作为繁殖材料，称为种芋，突出缺点是用种量大，繁殖系数低，种芋的贮藏和调运增加成本，限制了许多南方名优品种的北移和大面积推广。而且长期以来，由于采用无性繁殖方法，芋花叶病毒（Dasheen Mosaic Virus，DMV）病发生严重，导致种性退化，产量和品质的下降，是目前生产上迫切需要解决的问题。利用组织培养方法获得无毒或少毒再生植株，并在短时间内快速增殖，获得大量组培苗是解决这些问题的公认有效途径。但是人们在获得芋的组培苗后又面临一些新的问题，如组培苗难以保存，驯化移栽成活率低，远距离运输困难等。试管球茎虽然需要在试管苗的基础上进一步培养才能获得，但其是完善芋脱毒快繁商品化生产体系的有效方案。 为了改进芋的脱毒快繁技术，建立起高效、实用的芋良种繁育体系，作者在硕、博连读的五年时间内，首先着重研究芋脱毒快繁体系建立过程中的关键技术及其基础原理，取得了如下结果： 1．对建昌红梗芋和福鼎槟榔芋进行大田种植，田间观察结果表明：两个品种都出现与芋花叶病毒病描述相似的感染症状，发生率都达到60％以上。进一步的电镜观察结果表明：两个品种的感病叶片上都发现了与DMV形状、大小相似的病毒粒子，初步认为在这两个品种上普遍发生芋花叶病毒病。 2．在国内首次将苯基噻二唑基脲（TDZ）应用于不同基因型芋的组织培养中。与BA相比，TDZ的细胞分裂素活性至少高出一个数量级，0.1mg·L^-1的TDZ能有效地诱导四个基因型芋茎尖的萌动、生长、大量增殖丛生芽，促进试管苗根系发生，将根系活力提高2倍以上，显著提高了试管苗的驯化成活率；浓度为0.01mg·L^-1的TDZ能诱导魁芋类型的芋离体叶片切块产生再生芽点，转接后可增殖不定芽并形成再生植株。 3．研究不同培养方式和温度、光照条件对广西荔蒲芋，福建福鼎芋，建昌红梗芋和太仓香子芋试管球茎诱导的影响。试验结果表明：在以液体培养方式、温度为29℃（light）／20℃（dark）和光照时间为8 h／d时的条件下，试管球茎的诱导效率达到95％以上，单瓶试管球茎的最大鲜重和平均鲜重也达到4.5g和2.0g以上。 4．研究不同浓度的TDZ和KNO₃对四种基因型芋试管球茎诱导和发育的影响。结果表明：与浓度为5 mg·L^-1的BA相比，浓度为0.2 mg·L^-1的TDZ可以显著提高4种基因型芋的单瓶试管球茎的个数，平均提高幅度为分别为45.5％，64.0％，23.2％和16.8％，球茎的最大鲜重和单瓶总鲜重也都得到显著水平提高。浓度为50mmol·L^-1的KNO₃对芋试管球茎数量影响不大，但是对重量的影响较大，单瓶试管球茎的平均鲜重提高的平均幅度为 12．9％。5．在国内首次研究了不同浓度的水杨酸（SA）对四个品种芋试管球茎诱导和发育的影响。结果表明：与对照相比，培养基中附加浓度为 0．smmol． L’的 SA，将 LY、FY、XY和 HY四个品种芋试管球茎的平均鲜重分别提高 ZI．70、16．l0、17．50和14．30，最大鲜重分别提高12．60、16．00、11．0O和 10．5O，平均干重提高8．10、8．40。7．2％和 9二％。并且在此浓度下，SA具有调节试管球茎同期发育的作用，试管球茎大小分布集中，1刀《刀g重量的试管球茎趋多。6．以茎尖培养获得的红梗芋试管苗和试管球茎为材料，在国内首次研究芋试管苗和试管球茎连续两年大田种植的生长、产量和品质情况。第一年种植的结果表明：试管苗和试管球茎在生长期的植物学特性上与原种基本保持一致。由于在子芋个数上存在显著差异，试管苗和试管球茎折合 667m2产量分别比对照低 7．6％和 8石％。第二年种植的结果表明：试管苗和试管球茎7d后发芽率高于对照的 8厂％和 9．l％，生长期的植物学特性上与原种完全保持一致，折合667m‘产量分别比对照提高10．70和 10．20，比第一年分别提高35．7％和36．5％。红梗芋试管苗和试管球茎大田种植第二年所体现的增产潜力是巨大的，显示出脱毒复壮的效果。7．以红梗芋、香子芋和荔蒲芋为材料，研究这三种基因型芋试管苗在大田种植第一代的生产性能和遗传稳定性。实验结果表明：三种基因型芋试管苗在成叶数，最大叶宽，母芋重，子芋平均单重、子芋总淀粉含量和粗蛋白含量等各植物学特性上与普通对照无显著差异。由于在子芋个数上存在显著差异，三种基因型芋试管苗第一年折合667m‘产量低于对照。试管苗根尖染色体在形态和数月上与各对照都保持了一致。第一代芋球茎蛋白质SDS－PAGE电泳图谱以及酯酶和过氧化物酶同工酶电泳图谱都表明生化特性没有差别，具有遗传的稳定性。 作者在对芋、草萄等园艺作物进行组培研究的过程中，不断发现组培苗由于受环境条件的限制而出现各种生长障碍。国内外许多研究报道认为，组培苗生长不够健壮主要原因是组培小植株长期在密闭环境中生长，靠培养基中的糖进行异养，而导致更多还原

【Abstract】 Two (Colocasia esculenta L.Shott) is a kind of very important vegetable and medicinal plant, which has been cultivated in China for a long history. Up to now, taro is found to be one of the most salinity-tolerant vegetables in the world. Long period cultivation of taro will decrease the salinization degree of soil. So, it is useful in exploiting bench and sands.In conventional cultivation, taro reproduces through corms which results in low reproductive efficiency, difficulties in transportation and emergence of Dasheen Mosaic Virus(DMV). As a result of DMV, yield and quality of taro is decreased yearly which now is the most serious problem in practice. Getting plantlets in vitro through shoot-tip culture and reproduction in a short time is the effective and acknowleged method for solving this problem. But plantlets are soon faced with such new problems as low transplanting survival rate, difficulty in long distance transportation, being infected by DMV again, etc. Microcorm is the effective method in improving micropropagation system though they are need to be induced further.In order to improve the techniques of micropropagation and construction efficiency and practical reproduction system of virus-free taro, we devoted five time to study the key techniques and the mechanism in construction taro reproduction system. The results are as follows:1. Field survey of Colocasia esculenta Schott cv. Honggeng-yu (HY) and Colocasia esculenta Schott var. Fuding-yu(FY) indicated that: Similar infection symptom of Dasheen mosaic virus(DMV) were found in both of the two varieties ,and the infection rate was higher than 60%. Results of electron microscope observe proved that the shape and size of causal virus found from infection leaf was similar with DMV. A preliminary conclusion is that taro of the two varieties were infected by DMV.2. TDZ (Thidiazuron) was used as cytokinin in tissue culture of taro in different genotypes. Comparing as BA, 0.1mg - L-1 TDZ was more effective in inducing germinating and developing of buds, regenerating prolific caespitose buds via organogenesis, promoting rhizogenesis and activity of root system greatly, as a result, acclimation survival rate was improved significantly. When leaf segments, cut from in vitro plantlets, were placed on MS media containing O.lmg - L-1 TDZ, adventitious buds regenerated from segments. After transferred to propagated and rooted media, adventitious buds would proliferate and come into full plantlets.3. Plantles in vitro of taro of 4 genotypes were got through shoot-tip culture. Effect of cultural way, temperature and light on mocrocorm induction were studied. Results showed:under the condition of liquid culture, 29C (light) /20C(dark) and 8 hours light time per day, the induction rate and the fresh weight of microcorm reached the highest. If the fresh weight of microcorm is more than 0.8g, the mean sprouting rate of the 4 genotypes was more than 80%.4. Study on effect of different concentration of TDZ and KNO3 on induction and development of mocrocorm of taro. Results indicated that: as compared with 5.0mg/L BA, 0.2mg/L TDZ could increase the number of microcorms of 4 genotypes as high as 45.5%, 64.0%, 23.2 and 16.8%. The max fresh weight and total fresh weight of microcorm per vessel were also increased obviously. Though 50mmol/L KNO3 was not effective on number of microcorms, it could increase the mean fresh weight and total fresh weight of microcorm per vessel as high as 12.9% and 13.9%.5. Study on effect of different concentration of Salicylic acid(SA) on induction and development of mocrocorm of taro. Results indicated that: as compared with the control, 0.5mmol/L SA in medium could increased mean fresh weight of microcorm of taro of 4 genotypes respectively as high as 21.7%, 16.1%, 17.5% and 14.3%. ,increased max fresh weight respectively as high as 12.6%, 16.0%, 11.0% and 10.5%, increased mean dry weight respectively as high as 8.1%, 8.4%, 7.2% and 9.2%. 0.5mmol/L SA could regulated the development of major of microcorms in the s更多还原