等渗的NaCl与PEG胁迫对番茄幼苗蔗糖代谢的影响

为探讨NaCl胁迫与水分胁迫对番茄蔗糖秘累影响的异同,以番茄(Lycopersicon esculentum Mill.)品种辽园多丽为试材,采用营养液水培法,以50 mmol·L~(-1) NaCl及等渗的聚乙二醇(PEG-6000)为处理,研究了番茄幼曲叶片中糖含量和蔗谢代谢相关酶活性的变化.结果表明:等渗的NaCl和PEG处理均可提高番茄幼苗叶片中葡萄糖和果糖的含量,处理12d时果糖含量分别比CK提高了20.2%和32.2%;葡萄糖含量分别比CK提高了12.0%和18.9%;等渗的NaCl和PEG处理均提高了酸性转化酶活性,处理12d时分别比对照高12.34%和17.76%;PEG胁迫下番茄幼苗叶片中葡萄糖和果糖的含量及转化酶的活性高于NaCl胁迫.可见,盐胁迫和渗透胁迫下番茄叶片葡萄糖和果糖的积累主要是由于转化酶活性的提高引起的;与盐胁迫相比渗透胁迫下番茄叶片积累更多的可溶性糖,从而说明NaCl胁迫对番肺叶片糖代谢的影响主要是渗透胁迫.

Effect of Salt Stress and PEG Iso-osmotic Stresses on Tomato Sugar Metabolism

Tomato (Lycopersicon esculentum Mill.) cultivar 'Liaoyuan Duoli' was used by the method of water culture. It was respectively treated with 50 mmol·L~(-1) NaCl and PEG-6000 Iso-osmotic. The contents of soluble sugars and the related enzyme activities of sucrose metabolism were determined. The results showed that NaCl and PEG-6000 Iso-osmotic stresses enhanced the contents of fructose and glucose in tomato leaves, increased the activities of AI and NI, reduced the activities of SS and SPS.The effects of two stresses on sucrose contents were weak. The contents of fructose and glucose and invertase activities were higher under PEG stress than that under NaCl stress. These results suggested that NaCl and PEG stresses enhanced the contents of fructose and glucose in tomato leaves, which is due to changing that the activity of invertase activity affecting sugar accumulation. The contents of soluble sugars were higher under PEG stress than that under NaCl stress.