【作者】 孙晓波；

【导师】 李式军； 刘高琼；

【作者基本信息】 南京农业大学 ， 蔬菜学， 2002， 硕士

【摘要】 大蒜是一种栽培历史悠久的世界性蔬菜，主要靠鳞茎进行无性繁殖。大蒜的无性繁殖方式给大蒜的生产带来两个问题：一无性繁殖使大蒜病毒病积累，且广泛传播；二繁殖系数低。应用茎尖分生组织培养获得脱毒苗，是脱除大蒜病毒的行之有效的方法。大蒜脱毒苗培育技术现已基本成熟，目前许多品种都已获得脱毒苗。但大蒜离体培养繁殖系数过低，脱毒种苗生产成本相当昂贵，成为大蒜脱毒苗进入生产实用化的瓶颈。 一个蒜瓣可发出几十条根，数量多，取材方便，使笔者受到启发，以大蒜蒜瓣发出的根的根尖为外植体，对影响大蒜根尖直接分化不定芽的各种因素进行了详细的探讨，并进一步研究了根尖分化的不定芽的生长与增殖情况，旨在建立一套取材方便、操作简单、繁殖系数高的大蒜微繁新技术体系，以突破上述瓶颈，推动大蒜脱毒苗生产进入实用化、产业化。并对蔗糖及乙烯、PP₃₃₃两种生长抑制剂对鳞茎的形成与膨大效果进行了探讨，旨在增加试管鳞茎重量，促使试管鳞茎分瓣，进一步提高大蒜微繁系数。同时对试管鳞茎移栽后零代与子一代的情况作了调查，以验证根尖微繁体系的实用性。 1．大蒜根尖培养诱导不定芽 通过研究不同大蒜品种、蒜瓣生根培养时间、根尖长度及不同培养条件（温度，光照时间，培养基，糖的种类与浓度，pH值，激素配比等）对根尖直接分化不定芽的影响，表明本论文所研究的四个大蒜品种（徐州白蒜，太仓白蒜，二水早，金乡蒜）根尖分化不定芽的频率及不定芽数目存在品种间差异；在蒜瓣生根培养时间为4～8天时，切取长度为2～3mm的蒜瓣根尖进行培养，根尖分化不定芽的频率最高。由不同外植体诱导生成的试管苗再诱导生出的根的根尖均能直接分化不定芽，说明大蒜可通过根尖进行循环增殖，但蒜瓣发出的根的根尖分化不定芽的频率较高。大蒜根尖培养分化不定芽需要较高的温度，在15℃、20℃下培养时，根尖全部生长成为白色的根组织，没有不定芽的发生；在28℃、32℃下培养，根尖不定芽分化频率及不定芽数显著提高。长的光照时间能促进根尖分化不定芽，大幅度提高不定芽数目。不同基本培养基、糖的种类与浓度、pH值、激素配比等对根尖分化不定芽的影响的研究表明，根尖培养最适宜的基本培养基为MS盐+B+5有机和MS培养基，蔗糖20～50g／L或白糖30g／L，BA2.0～5.0mg／L，NAA1.0mg／L，pH5.8～6.2。 2．大蒜根尖分化的不定芽的继代培养 以大蒜根尖培养诱导分化的不定芽为试验材料进行继代培养，以调查研究根尖在不同的根尖启动培养基上分化的不定芽的生长与增殖情况，不同基掷养基、不同激素浓度组合对大蒜根尖分化的不定芽的生长与增殖的影响，结果表明，根尖在含BAI omg／L，NAAlmg／L的起动培养基上分化的不定芽在继代培养时生成的试管苗最多，根尖在含M吧／L，NAAO．ling／L起动培养基上分化的不定芽在继代培养时的长势最强；不定芽生长的最适培养基为MS盐巾；有机或B；刊．oms／LBA叩．05mg儿NAA，不定芽增殖的最适培养基为MS盐＊；有机或B；＋0．sing／LBA。 3．大蒜试管鳞茎的培育与田间表现 以 B；为基本培养基，研究蔗糖浓度、乙烯、PP；；；对大蒜试管鳞茎形成与膨大的影响，表明蔗糖浓度提高到9 og／L能显著提高鳞茎形成率与重量；加入乙烯、PP；；；对鳞茎的形成与生长均有显著促进作用；在BS叫0g／L蔗糖八．0 mg／LPP；；；的培养基上，鳞茎生长效果最佳，可达31hg；在BS叫0；／L蔗糖d．0 m；／LPP；；；的培养基上，大蒜试管鳞茎能分瓣，分瓣率达33．1％。试管鳞茎的大小与幼苗的萌发、生长及鳞茎形咸的大小相关，3 0 omg以上的鳞茎萌发率高，生长健壮，能形成较重的鳞茎。试管鳞茎移栽后，零代生长正常，但植株矮小，形成的鳞茎小，多数为独头蒜，少数分瓣，但瓣数少；子一代生长正常，植株的叶数、株高、最大叶宽与零代相比，均显著增大，形成的鳞茎也能正常分瓣；鳞茎瓣数、重量与零代相比，显著增大，但与对照相比要小，可望在子二代达到与对照无差异或超过对照。更多还原

【Abstract】 Garlic (Allium sativum L.) is a worldwide vegetable and had been cultivated since ancient times. Due to its sexual sterility, garlic is propagated vegetatively through cloves or bulbs. Two main problems associated with the vegetative propagation of garlic are (1) perpetuation and wide spread of viral infection and (2) low propagation rate.Shoot-tip culture is proved to be an effective method for producing virus-free garlic seedlings. However, because of low micropropagation rate, virus-free plantlets are still very expensive which limits their practical use.This study focuses on direct shoot regeneration from garlic root tips and shoot proliferation for speeding up multipropagation of virus-free garlic.1. Induction of the adventitious buds from root tips in garlicUsing MS as basic medium, the effect of different varieties, rooting time, root-tip length and culture condition (temperature, photoperiod, basic media, sugar sources and concentration, pH value and different hormone concentration and combinations) on direct adventitious shoot formation from garlic root tips was studied. The results showed that 2~3mm root tips from the cloves rooting for 4-8 days have a high frequency bud initiation. The induction rate and the number of adventitious buds varied with varieties. Root tips from different rooted shoots induced from different explants all can directly regenerate adventitious buds and virus-free garlic can be cycly multiplicated through root-tip culture. The differentiation rate of buds of root tips inducted from plantlets from stem tips and root tips and adventitious shoot number was low than that from garlic cloves. Root tips had no bud regeneration when they were cultured at 15C or 20 C and the induction rate and the number of buds increased with the rise of temperature when they were cultured above 28 C. Continuous light had a positive effect on adventitious bud formation and number. The optimal medium for root tip culture was MS salt+B5 organic medium or MS containing sucrose 20~50g/L, BA 2.0~5.0mg/L, NAA1.0mg/L,at pH5.8~6.2.2. Subculture of adventitious buds from root tips in garlicThe growth and proliferation of adventitious buds from different initiation media were investigated. The results indicted that there were more shoots per explant on the initiation medium containing lOmg/LBA, Img/LNAA and adventitious buds from the initiation medium containing 2.0mg/LBA, 0.Img/LNAA grow vigorously. The optimal medium for adventitious bud growth was MS salt+B, organic (or 65) +1.0mg/LBA+0.05mg/LNAA and The optimal medium for adventitious bud proliferation was and MS salt+Bs organic (or 85) +0.5mg/LBA.3. Bulblet formation and swelling of Garlic in vitro and performance in field85 as basic medium, the study on effect of sucrose concentration ,ethephon and PPsss on bulblet induction and swelling of Garlic in vitro demonstrated that bulblet formation andswelling were significantly enhanced by increasing sucrose to 90g/L, Ethephon and had positive effects on bulblet fomation and swelling, on the 85 medium supplemented with sucrose 90g/L, PP333 1.0mg/L, bulblet swelled best, fresh weight can reach 312mg, and on the medium containing 90g/L sucrose and 2.0mg/LPPs33, 33.1% bulblets tillered. Bulblet fresh weight was related with seedlings germination, growth, and bulb formation. Bulblet above 300mg had higher germination rate, seedlings grew strong and produced heavier bulb. Bulblets were transplanted into pots, and zero generation grew normally, but plants were short and produced small bulbs with few clovs. First generation grew normally, and plant leaf number, height, leaf width significantly increased compared with zero generation. Ffirst generation can form much heavier bulb than zero generation with more clovs, but still lighter compared with control. It is possible that second generation has no difference with control or surpass control.更多还原