NaCl胁迫对黄花菜生长和生理特性的影响

Growth and Physiological Characteristics of Daylily Plants under NaCl Stress

为探明黄花菜的耐盐性及其生理机制,该试验以大同黄花菜为材料,采用砂培法,以正常营养液为对照(CK),用不同浓度(50、100、150、200、250mmol·L^(-1))NaCl溶液浇灌大同黄花菜,分别于处理后5、10、15、20、25d测定生长指标和生理指标,以明确NaCl胁迫对大同黄花菜生长、膜脂过氧化以及有机渗透调节物质含量的影响。结果表明:(1)随NaCl浓度提高,黄花菜根长和根系鲜质量先增大后减小,其他生长指标则逐渐显著降低,同时地上部含水量变化较小,根系含水量明显增加。(2)黄花菜叶片叶绿素a、叶绿素b和类胡萝卜素含量随NaCl浓度提高均明显降低。(3)随NaCl浓度提高,黄花菜叶片丙二醛含量和POD活性逐渐显著增加;抗坏血酸含量在胁迫后20d明显增加,25d时呈先增加后降低的变化趋势,并在150mmol·L^(-1) NaCl胁迫下达到最大值;SOD活性在处理后10d先增加后降低,在200mmol·L^(-1) NaCl处理下达到最大值,15d后随NaCl浓度提高而显著增加。(4)随NaCl浓度提高,叶片脯氨酸含量逐渐显著增加,可溶性糖含量明显降低,可溶性蛋白含量在短期内逐渐增加,在胁迫15d后呈先增加后降低的变化趋势,在150mmol·L^(-1) NaCl下达到最大值。研究发现,NaCl胁迫对黄花菜叶片光合色素合成的抑制和过氧化伤害程度均随浓度增加而增大;植株自身抗氧化能力和渗透调节能力在盐胁迫下明显提高,一定程度上缓解了盐胁迫对其植株的伤害,但仍不足以消除胁迫带来的不利影响,使得黄花菜植株生长受到显著抑制;黄花菜对NaCl胁迫的耐性较强,植株在250mmol·L^(-1)高盐胁迫下仍能存活。

To explore the salt-tolerance and its physiological mechanism of daylily,with the normal nutrient solution as control,the experiment studied the effects of NaCl stress on the growth,lipid peroxidation and organic osmotic substances contents of Datong daylily in sand culture by irrigating the different concentrations（50,100,150,200,250 mmol·L（-1））of NaCl solution and measuring the growth and physiological indicators at 5,10,15,20,25 dafter treatment.The results showed that：（1）with the increase of NaCl concentration,the root length and root fresh weight were increased and then decreased,the other growth indexes were decreased significantly,and the aboveground water content was relatively stable,and root water content was increased obviously.（2）The contents of chlorophyll a,chlorophyll b and carotenoid in leaves of daylily were decreased obviously with the increase of NaCl concentration.（3）With therise of NaCl concentration,the MDA content and POD activity were increased drastically,the AsA content was increased within 20 dafter treatment,and showed the trend of＂increase-decrease＂and reached the maximum at 150 mmol·L（-1） at the 25 th day.The SOD activity showed the law of＂increase-decrease＂and reached the peak value at 200 mmol·L（-1） within 10 dafter treatment,and was increased significantly with the rise of NaCl concentration after 15 d.（4）With the increase of NaCl concentration,the proline content was increased drastically,the soluble sugar content was decreased obviously,the soluble protein content was increased with the rise of NaCl concentration in short period,and showed the trend of＂increase-decrease＂and reached the maximum at 150 mmol·L（-1） NaCl after 15 d.The research illustrated that the greater the NaCl concentration,the greater the inhibition degree to the photosynthetic pigment synthesis and the peroxidation damage to the daylily plant.The abilities of antioxidance and osmotic adjustment of plant under stress were increased obviously,but the change could not eliminate the adverse effect by NaCl stress.It made that the growth of daylily plant was reduced significantly.The salt-tolerance of daylily was very strong,the plant can survive under 250 mmol·L（-1） NaCl stress.