外源水杨酸对氯化钠胁迫下番茄幼苗糖代谢的影响

Effects of salicylic acid on sucrose metabolism of tomato seedlings under NaCl stress

采用营养液水培法,用100、300和500mg·L-1不同浓度的水杨酸(SA)处理‘辽园多丽’番茄幼苗,测定在NaCl胁迫下番茄幼苗叶片果糖、葡萄糖、蔗糖含量和蔗谢代谢相关酶活性(酸性转化酶AI、中性转化酶NI、蔗糖磷酸合成酶SPS、蔗糖合成酶活性SS)的变化.结果表明:SA处理叶片可以维持或提高NaCl胁迫条件下番茄幼苗叶片果糖、葡萄糖含量及AI、NI、SPS和SS活性,其最高值分别比单纯NaCl处理植株增加30.0%、31.1%、24.7%、27.9%、22.0%和24.5%;但对NaCl胁迫条件下番茄幼苗叶片蔗糖含量的影响不大.表明水杨酸可以通过提高NaCl胁迫下番茄叶片转化酶活性来提高番茄叶片果糖和葡萄糖含量,从而缓解NaCl胁迫对番茄的伤害,其中以500mg.L-1的SA处理效果较理想.

A water culture experiment was conducted with the seedlings of tomato （Lycopersicon esculentum Mill. ） cuhivar Liaoyuanduoli to study the effects of salicylic acid （SA） on their sucrose metabolism under NaCl stress. The seedlings were treated with different concentrations （ 100, 300, and 500 mg· L^-1） of SA, and the contents of sucrose, glucose, and fructose as well as the related enzyme activities of sucrose metabolism, including acid invertase （AI）, neutral invertase （NI）, sucrose phosphate synthase （SPS） , and sucrose synthase （SS） , in seedling leaves were determined. Under NaCl stress, SA could maintain or enhance the leaf fructose and glucose contents and the leaf AI, NI, SPS and SS activities, with the highest increment of fructose and glucose contents being 30. 0% and 31.1% and that of AI, NI, SPS and SS activities being 24.7%, 27.9%, 22.0% and 24. 5% , respectively, in comparing with no SA application, while had less effect on the leaf sucrose content, which suggested that SA could play a protective role in the NaCl-tolerance of tomato seedlings via enhancing the leaf invertase activity to increase leaf fructose and glucose contents. The best alleviating effect was observed at 500 mg· L^-1 of SA.