低温胁迫下外源水杨酸对玉米幼苗生理特性的影响

Physiological Effects of Exogenous Salicylic Acid on Maize Seedlings under Low Temperature Stress

采用叶面喷施外源水杨酸（SA）0、25、50、100、150mg／L不同浓度处理，比较分析低温胁迫下玉米幼苗株高、根长、地上部和地下部干重等农艺指标和相对含水量、相对电导率、Fv／Fm、Pn、MDA含量、SOD和POD活性等生理生化指标的变化。结果表明，在低温抑制玉米幼苗生长条件下，低浓度SA（25—50mg／L）减缓玉米幼苗生长受抑制程度，其中，50mg／LSA处理效果最佳，与对照比较，玉米自交系B125和昌7—2株高分别增加12．9％、14．5％，相对含水量分别提高60．4％、64．5％，相对电导率分别降低47．6％、57．5％，POD活性分别增加29．6％、35．6％。适宜浓度的SA在常温条件下可促进玉米幼苗的生长和缓解低温胁迫对玉米幼苗造成的伤害。

SA solutions were sprayed on the leaf surface at the concentration of 0, 25, 50, 100 and 150 mg/L separately and changes of agronomic indexes（plant height, root length, dry weight of aboveground and underground） and physiological and biochemical indexes （relative water content, relative electric conductivity, Fv/Fm, Pn, MDA content, SOD and POD activity） were studied. The results showed that under the condition of low temperature, low concentrations of SA（25-50 mg/L） relieved the growth inhibition degree of maize seedlings, with the concentration of 50 mg/L having the best effect. Under low temperature conditions, exogenous SA of 50 mg/L increased the plant height of B125 and Chang7-2 by 12.9% and 14.5%, respectively; increased the relative water content by 60.4% and 64.5%; reduced the relative electric conductivity by 47.6% and 57.5%; increased the POD activity by 29.6% and 35.6%. However, high concentration SA（150 mg/L） had lower effects in relieving the growth inhibition. In conclu- sion, exogenous SA of appropriate concentrations can promote the growth of maize seedlings under normal temperatures and relieve the low temoerature-iniuries.