Zhang Xinguo, Chen Xianyang, Jiang Dan, Li Yinxin
Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
Sheng Wu Gong Cheng Xue Bao. 2008 Jul;24(7):1202-9.
In order to obtain salt-tolerant calli of Dandelion (Taraxacum officinale Weber), calli were induced from leaf explants of Dandelion on Murashige and Skoog's medium supplemented with 2.0 mg/L 6-benzyladenine and 0.5 mg/L 2,4-dichlorophen oxyacetic acid With 1.5% NaCl as selection pressure, most calli became brown and dead, whereas some new cell clusters appeared at the edge of the brown calli after 2 to 3 weeks. The survived cells were picked out and sub-cultured every 3 weeks onto the fresh selection medium and salt-tolerant calli were finally obtained through 4 continuous selections on the selection medium supplemented with 1.5% NaCl. Salt-tolerant calli increased steadily under a fixed NaCl stress though their relative growth rate decreased with increased NaCl concentration whereas the control calli which were sub-cultured by 4 continus selections on salt free medium ceased to grow under the same condition. This result indicated that the salt-tolerance of the selected calli is improved and this character is stable. Compared with the control, the SDS-PAGE pattern of the salt-tolerant calli had a unique 34 kD protein band. Its 30 kD and 18 kD protein bands were up-regulated. Further more, within the NaCl stress range up to 1.5%, the activities of antioxidant enzymes such as super oxidase dimutase, peroxidase and catalase, and the proline contents of the salt-tolerant calli were higher than those of the control. The results indicated that the selected calli with improved and stable salt tolerance were cell variants. The accumulation of the organic compatible solutes including proteins and the enhanced antioxidant capabilities in the salt tolerant calli are the two ways for them to regulate their osmotic homeostasis and alleviate the secondary reactive oxygen spexies damage respectively.
为了获得耐盐的蒲公英愈伤组织，以蒲公英叶片外植体为材料，在添加了2.0 mg/L 6-苄基腺嘌呤和0.5 mg/L 2,4-二氯苯氧乙酸的Murashige和Skoog培养基上诱导愈伤组织。以1.5% NaCl作为选择压力，大多数愈伤组织变褐死亡，而2至3周后在褐色愈伤组织边缘出现了一些新的细胞团。挑选存活的细胞，每3周转接至新鲜的选择培养基上，最终通过在添加1.5% NaCl的选择培养基上连续4次筛选获得耐盐愈伤组织。在固定的NaCl胁迫下，耐盐愈伤组织稳定增加，尽管其相对生长速率随NaCl浓度增加而降低，而在无盐培养基上连续4次继代培养的对照愈伤组织在相同条件下停止生长。这一结果表明，所选愈伤组织的耐盐性得到了提高且该特性稳定。与对照相比，耐盐愈伤组织的SDS-PAGE图谱有一条独特的34 kD蛋白带。其30 kD和18 kD蛋白带上调。此外，在高达1.5%的NaCl胁迫范围内，耐盐愈伤组织的超氧化物歧化酶、过氧化物酶和过氧化氢酶等抗氧化酶活性以及脯氨酸含量均高于对照。结果表明，所选耐盐性提高且稳定的愈伤组织是细胞变异体。耐盐愈伤组织中包括蛋白质在内的有机相容性溶质的积累以及抗氧化能力的增强分别是它们调节渗透稳态和减轻次级活性氧损伤的两种方式。
