甘露糖对小麦不同外植体愈伤诱导及生长的影响

为了给以磷酸甘露糖异构酶基因作为筛选标记的小麦遗传转化提供资料,以小麦栽培品种扬麦158和华麦13的茎尖、叶基、成熟胚为外植体,研究了不同甘露糖浓度对这些外植体愈伤组织诱导和生长培养的影响.结果表明,10 g/L的甘露糖使茎尖的出苗和生根受到明显抑制,而茎尖幼苗对甘露糖的耐受力较强,15 g/L甘露糖才能有效抑制幼苗生长.叶基在5 g/L甘露糖时,其愈伤组织诱导率降低55%,而成熟胚在10或15 g/L甘露糖时的愈伤组织诱导率与叶基在5 g/L甘露糖时相当.这些结果说明,在以小麦叶基、茎尖和成熟胚为外植体的PMI/甘露糖筛选中,可分别以5、10、15 g/L甘露糖作为筛选压.另外,培养时间不同的外植体或培养物对甘露糖敏感性不同,在培养早期阶段筛选时,可选较低的甘露糖筛选压,而在后期培养阶段进行筛选时,可适当提高筛选压.

Effect of Mannose on Callus Induction and Growth of Different Explants Derived from Wheat

Explants derived from shoot apices, leaf bases and mature embryos of elite wheat varieties were assayed for their callus induction and growth on culture media containing various concentrations of mannose as carbon sources. Results showed that a clear inhibitory effect on the growth and rooting of shoot apices was observed in the presence of 10 g/L mannose, whereas 15 g/L was required to inhibit the growth of young seedlings derived from shoot apices. Callus induction from leaf bases was inhibited with 5 g/L mannose, resulting in a reduction of callus formation up to 55%. For mature embryos, callus induction and growth rate were inhibited in the presence of 10 g/L or 15 g/L mannose. These results indicated that 5 g/L, 10 g/L and 15 g/L mannose were required for the explants derived from shoot apices, leaf bases and mature embryos, respectively, when mannose was used for positive selec,tions in transgenic wheat plants. In addition a lower concentration of mannose can be used for the initial induction and culture of wheat explants while an increasing mannose can be deployed at the later stages.