盐胁迫下ABA预浸种对向日葵幼苗的缓解效应

浸种预处理可以缓解外界环境胁迫对植物的影响。以向日葵为材料，研究10 mg/L脱落酸(ABA)预浸种对盐胁迫下(150 mmol/L NaCl)向日葵幼苗相应生理参数的影响。实验结果表明：与正常生长的向日葵幼苗(A0)相比，150 mmol/L NaCl胁迫(A1)处理使得幼苗中叶绿素a、叶绿素b、类胡萝卜素、色素总含量分别降低了7.8%、3.6%、0.5%、10.9%；经ABA浸种处理后，各种光合色素含量不同程度提高；比较对照组(A0)、NaCl胁迫组(A1)、ABA浸种对照组(B0)以及ABA+NaCl胁迫组(B1)中各种色素的含量，发现B1组幼苗的色素含量最高，而A1组幼苗的色素含量最低。在NaCl(150 mmol/L)胁迫条件下，A1、B1中脯氨酸含量分别增加了4.4倍、4.28倍；而在非ABA浸种的对照组(B0)中，脯氨酸含量是对照组(A0)的2.23倍，这说明即使在无盐胁迫条件下，ABA浸种可以同样刺激幼苗中脯氨酸合成、积累。SOD、POD、CAT 3种酶活性结果显示，POD活性占主要优势地位，其活性最高的出现在B1组，活力最低的出现在A1组；同对照组(A0)相比，其他3种处理方式使得幼苗中CAT活性明显升高(P<0.05)，而SOD活性明显降低(P<0.05)；但是这3组间CAT、SOD活性差异不明显(P>0.05)。上述实验结果说明，ABA的预浸种可以提高脯氨酸含量、调节抗氧化物酶的活性，从而维持胁迫条件下植物光合能力，缓解盐胁迫的伤害。

Effects of ABA Pretreatment on the Seedlings of Sunflower Under the NaCl Stress

Pretreatment in plants is recognized as a valuable strategy to eliminate the effects of salt stress. The study evaluated the effects of ABA pretreatment on the photosynthetic pigments, proline concentration, and the antioxidative mechanisms of sunflower under 150 mmol/L NaCl stress. It was found that the concentrations of chlorophyll a, chlorophyll b, carotenoid and total pigments were reduced by 7.8%, 3.6%, 0.5%, 10.9%,respectively. All kinds of pigments concentrations were increased after using ABA pretreatment. Compared within 4 treatments, the most abundant pigment was from the seedlings of B1, while the least pigment was from the seedlings of A1. The concentrations of proline were increased by 4.4 times （A1） and 4.28 times （B1） under salt stress, while the proline concentration of B0treatment was increased by 2.23 times. The result showed that pretreatment with ABA stimulated the accumulation of proline under the control condition （A0）. Analysis of the antioxidative enzymes CAT, POD, SOD revealed that ABA pretreatment affected antioxidant enzyme activities,especially POD activity. The most abundant activity was from the seedlings of B1, while the least activity was from the seedlings of A1. Compared with the control, the CAT activity was increased significantly （P0.05）,while the SOD activity was decreased significantly （P0.05）. The results suggested that ABA pretreatment enhanced the proline concentration, regulated the activities of antioxidants, and maintained the photosynthetic capacity of sunflower seedlings under the salt stress.