Abstract: In order to provide theoretical basis for further study on salt tolerance mechanism of safflower seedling, this paper observed the response of safflower to NaCl stress during germination and seedling stage, and determined the salt tolerance thresold of safflower seedlings. The seeds of safflower were soaked in distilled water and NaCl solution of different concentrations（0.06 mol/L, 0.12 mol/L, 0.18 mol/L, 0.24 mol/L, 0.30 mol/L）cultivated by sand method and irrigated with Hoagland nutrient solution with different concentrations of NaCl solution at seedling stage. The response of safflower seedlings to NaCl was observed by measuring the morphological indexes, the content of MDA, the activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves. The results showed that: ① In the group of distilled water and NaCl solution, the plant height and root length of seedlings decreased with the increase of NaCl concentration, and the inhibition of the underground part was stronger than that of the aerial part. ② In the group of distilled water and NaCl solution, with the increase of NaCl concentration, the activity of SOD increased first, and then decreased. The maximum value was achieved under the treatment of 0.06 mol/L NaCl. The activity of POD increased significantly. Under 0.18 mol/L NaCl treatment, the activity of POD enzyme was the highest. At the same irrigated concentration, POD enzyme activity in NaCl immersion was greater than that in distilled water immersion. ③ In the distilled water immersion group, with the increase of NaCl concentration, the content of MDA increased. In NaCl immersion group, with the increase of NaCl concentration, the content of MDA decreased first, and then increased. The content was lowest at 0.06 mol/L NaCl concentration. Under 0.18 mol/L NaCl treatment, the content of MDA was still lower than that of the authentic group. The content of MDA in the NaCl immersion group was lower than that in the distilled water group. Above results indicated the salt tolerance of safflower seeds was improved after soaking with NaCl, and the threshold of NaCl tolerance of safflower seedlings was determined to 0.18 mol/L.

Key words: Carthamus tinctorius L., seedling, salt stress, morphological index, physiological index

摘要： 观察红花在萌发期和幼苗期对NaCl胁迫的响应特征，确定红花幼苗的耐盐阈值，为深入研究红花幼苗的耐盐机理提供理论依据。以蒸馏水和不同浓度NaCl溶液浸泡（0.06 mol/L、0.12 mol/L、0.18 mol/L、0.24 mol/L、0.30 mol/L）红花种子，沙培法培养，苗期浇灌含有不同浓度NaCl的霍格兰营养液。通过测定红花幼苗形态指标、丙二醛(MDA)含量以及叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)的活性来考察红花幼苗对NaCl的响应。结果表明：①蒸馏水浸泡和NaCl浸泡组中，幼苗株高与根长均随NaCl浓度的增高而下降，且对地下部分抑制强于地上部分。②蒸馏水浸泡和NaCl浸泡组中随NaCl浓度的增加，SOD酶活性先增高后下降，在0.06 mol/L NaCl处理下达到最高值；POD酶活性显著增强，在0.18 mol/L NaCl处理下POD酶活性最高；同一浇灌浓度下，NaCl浸泡组POD酶活性均大于蒸馏水浸泡组。③蒸馏水浸泡组，MDA含量随着NaCl浓度的增高而增加；NaCl浸泡组，MDA含量先减少后增加，在0.06 mol/L NaCl处理下含量最低，在0.18 mol/L NaCl处理下含量仍比对照组低。NaCl浸泡组中MDA含量整体低于蒸馏水浸泡组。表明红花种子经过NaCl浸泡，幼苗耐盐性提高，初步确定红花幼苗的耐NaCl阈值为0.18 mol/L。

关键词: 红花, 幼苗, 盐胁迫, 形态指标, 生理指标