Studies on bulb formation and dormancy in bulbous plants by molecular biological approach

用分子生物学的方法对诱导球茎形成和诱导球茎休眠是同一现象的假说进行了研究。以风信子（Hyacinthus orientalis L. cv）离体未成熟叶片为外植体。代尔夫特蓝)，在含NAA和BA的MS培养基上25℃培养。5℃冷处理后外植体鳞茎形成4个，而未经冷处理的外植体鳞茎形成受到抑制。ABA促进球茎形成，而无需冷处理。通过flundone，可以抑制冷处理外植体的鳞茎形成。在成球条件下，内源ABA含量增加。这些结果表明，球茎形成受低温诱导和ABA调控。因此，控制方法是通过冷处理或未经冷处理的BAB可获得球茎形成条件，而非球茎形成条件则通过非冷处理或氟酮冷处理获得。对风信子球茎形成过程中低温和ABA诱导的基因进行了差异展示分析。冷处理和未冷处理的芽部样品的PCR扩增片段存在差异。6个差异PCR扩增片段在冷处理和ABA处理中均有表达，其中2个片段在冷处理和ABA处理中均被抑制。在两种处理中观察到的cDNA扩增片段可能与风信子球茎形成有关。利用低温法对18个特定基因片段的cDNA克隆（称为HL克隆）进行部分测序。8个HL克隆与FASTA程序鉴定的序列同源性在80%以上。低温和ABA诱导的HL克隆与拟南芥（a.thaliana）或苜蓿（o.s ativa）的基因组DNA同源。3个HL无性系与巴塔塔淀粉磷酸化酶基因部分同源。一些HL克隆与功能已被证实的基因或mrna同源。功能尚未明确的HL克隆可能是与球茎形成相关的新基因。少

Molecular biological studies were used to investigate the hypothesis that the induction of bulb formation and the induction of bulb dormancy are the same phenomenon. Shoot explants were taken from in vitro immature leaves of hyacinth (Hyacinthus orientalis L. cv. Delft Blue) and cultured at 25℃ on MS medium containing NAA and BA. The explants formed bulbs four after the cold treatment at 5℃, whereas bulb formation was supressed without cold treatment. ABA promoted bulb formation without cold treatment. By flundone, bulb formation of the cold treated explants was inhibited. Under bulb-forming conditions, endogenous ABA content increased. These results suggest that bulb formation is induced by low temperature and regulated by ABA. Thus, the controlling methods are bulb forming conditions are obtainable by cold treatment or BAB without cold treatment and non-bulb forming conditions are by non-cold treatment or fluridone with cold treatment.Differential display analysis of genes induced by … More low temperature and ABA in bulb formation of hyacinth was conducted. Differential PCR amplified fragments between cold-treated and non-cold-treated shoot samples were observed. Six differential PCR amplified fragments were commonly expressed both in the cold and ABA treatments, and two were suppressed in both treatments. The cDNA amplified fragments observed in both treatments might be related to bulb formation in hyacinth.The partial sequences of the cDNA clones obtained from 18 specific gene fragments by low temperature (designated as HL clones) were carried out. Eight HL clones had over 80% identity with identified sequences with FASTA program. The HL clones of cDNA induced by low temperature and ABA were homologous to genome DNA of A. thaliana or O. sativa. Three HL clones showed partial identity with starch phosphorylase gene of I. batatas. Some HL clones were homologous to genes or mRNAs of which the function had been suggested. It is possible that HL clones of which the functions were not clarified are novel genes related to bulb formation. Less