在1/3海水培养基上筛选豆瓣菜耐盐变异体

Screening of Salt Tolerant Watercress Variants on Natural Seawater Contained Medium 

系统地研究了豆瓣菜（ＮａｓｔｕｒｔｉｕｍｏｆｉｃｉｎａｌｅＲ．Ｂｒ．）茎段外植体对６ＢＡ、ＮＡＡ和２，４Ｄ的反应。确定了ＭＳ培养基附加６ＢＡ２．０ｍｇ／Ｌ，２，４Ｄ０．２ｍｇ／Ｌ为豆瓣菜愈伤组织诱导、继代培养基；ＭＳ培养基附加６ＢＡ４．０ｍｇ／Ｌ为芽再生培养基；ＭＳ基本培养基为植株的生根和扦插繁殖培养基。将３２５个豆瓣菜茎切段外植体接种到含１／３海水的愈伤组织诱导培养基上，１７块外植体上可长出耐盐愈伤组织。耐盐愈伤组织在１／３海水浓度的培养基上生长速度与对照愈伤组织在无盐培养基上的生长速度基本相近。将耐盐愈伤组织转接到无盐的再生培养基上，芽再生的频率与对照愈伤组织相近。再生芽总数超过１０００。将８３个再生芽转移到含盐但无激素的培养基上，开始时植株生长几乎被抑制，接种４０ｄ后，１６个植株长出了生长迅速的腋芽，但对照无此现象发生。将耐盐愈伤组织转至含盐的再生培养基上，虽然大部分愈伤组织在接种１０ｄ后出现了绿点，但３０块愈伤组织最后只有５块出了芽点，真正生长正常的芽只有２个。将上述两类生长正常的芽转至无激素含盐培养基上扦插繁殖，得到１８个正常生长的耐盐豆瓣菜株系。用ＲＡＰＤ技术对其中１０个株系ＤＮＡ水平?

The responses of stem segments of watercress ( Nasturtium officinale R. Br.) to 6 BA,NAA and 2,4 D were studied. MS medium supplemented with 2.0 mg/L 6 BA, 0.2 mg/L 2,4 D was used for callus initiation and maintainance. MS medium supplemented with 4.0 mg/L 6 BA was suitable for plant regeneration and MS medium without plant hormone supplement was used for rooting and plant propagation. For screening of salt tolerant calli, stem segments of watercress were plated onto callus initiation medium containing 1/3 natural seawater. Seventeen out of the 325 plated explants produced calli. The growth curves demonstrated that the growth rate of salt tolerant calli on saline medium almost matched that of the control calli on normal medium. Some of the salt tolerant calli were transferred to the normal regeneration medium or saline regeneration medium to induce plant regeneration. In the first case, buds and shoots were regenerated in the same way as those of control calli on normal regeneration medium. More than 1000 regenerated shoots were obtained of which 83 regenerated shoots were cut and transferred to saline MS base medium. At first, all shoot growth was inhibited, but 40 days after the transfer, rapid growing axillary shoots were observed on 16 of the original shoots but none on the control shoots on saline MS base medium. Moreover, green spots appeared on most calli 10 days after they were transferred to saline medium, however buds appeared only on 5 calli from the 30 transferred calli and at the end only 2 rapid growing shoots were obtained from two calli. In total, 18 variant lines were obtained through propagation of the salt tolerant shoots on saline MS base medium. RAPD analysis was performed in 10 of the 18 salt tolerant variant lines and DNA variation was detected in all the tested variant lines.