水杨酸对菊芋耐高氯酸盐胁迫的影响

Effect of Exogenous Salicylic Acid on the Tolerance of Helianthus tuberosus L.to ClO4^-Stress

为探究ClO4-胁迫下外源水杨酸(salicylic acid,SA)对菊芋(Helianthus tuberosus L.)的生理调节作用,以徐州、潍坊和南京3个不同产地耐盐菊芋为试材,进行液培处理,研究NaClO4胁迫条件下(50 mmol/L),SA不同时间间隔喷施处理对菊芋幼苗的形态学指标、根系活力和光合作用及抗氧化能力的影响。结果表明,ClO4-对菊芋幼苗的生长发育可产生不同程度的毒害作用,喷施SA可有效减轻其对植株的胁迫损伤,且不同产地菊芋的变化趋势相似,植物鲜重、叶面积、株高和根长明显改善,叶片中叶绿素含量及荧光参数显著升高,且每天喷施缓解效果最大;而根系活力在间隔1天喷施效果最佳。同时,H2O2含量呈现出随SA喷施频率的增加而上升趋势,当喷施间隔为2天时,平均增加47.69%,喷施间隔为1天时平均增量为50.93%,每天喷施时平均增幅达到最大值56.80%;且超氧化物岐化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活力得到提高,丙二醛(MDA)及游离脯氨酸含量显著降低(P<0.05)。表明SA可通过诱导H2O2作为信号分子增强植株耐受ClO4-的能力。通过灰色关联度分析可知,喷施SA对ClO4-胁迫下叶绿素荧光参数和根系活力影响最大。综上所述,叶面喷施50μmmol/L SA主要是通过影响菊芋叶片和根系,激发H2O2调控抗氧化酶活性的变化,参与体内渗透调节来保护植株光合系统和根系活力,降低ClO4-胁迫对菊芋的伤害,且每天喷施处理的缓解效果最佳,这为菊芋在ClO4-污染土壤中的栽培提供理论指导。

To explore the physiological regulation of exogenous salicylic acid(SA)on Helianthus tuberosus under ClO4-stress,salt-tolerant Helianthus tuberosus L.from three different sites in Xuzhou,Weifang,and Nanjing were used as materials.The effects of exogenous SA on growth,root vitality,photosynthesis,and antioxidant capacity under 50 mmol/L NaClO4 stress were studied by using foliar application and nutrient solution culture to cultivate plants.The results showed that ClO4-stress had different degrees of toxic effects on the growth and development of Helianthus tuberosus seedlings.Spraying exogenous SA could effectively reduce the stress damage to the plants,with similar change trend in Helianthus tuberosus L.from different sites.The biomass content,leaf area,plant height,and root length,as well as the chlorophyll content and fluorescence parameters of the leaves increased significantly,and achieved the maximum alleviation effect under SA spraying every day,while the root activity was better under the SA treatment every two days.At the same time,the content of H2O2 showed an increasing trend with the increases of SA spraying frequency.The increase in H2O2 content of each species was 47.69%when spraying SA every three days,while the increase rate was 50.93%for every two day,and 56.80%for every day.The activities of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)were increased,and the content of both malondialdehyde(MDA)and free proline were significantly decreased(P<0.05),indicating that SA induced H2O2 to act as a signaling molecule to enhance the tolerance of plants in the ClO4-environment.The grey correlation analysis showed that the application of SA had the greatest influence on the chlorophyll fluorescence parameters and root activity of perchlorate stress.In summary,foliar application of 50μmmol/L SA mainly affected the leaves and roots of Helianthus tuberosus.The ClO4-stress damage could be relieved by stimulating H2O2 to participate in the changes of antioxidant enzymes,and regulating the osmotic adjustment ability of plants to protect the photosynthesis and root activity.Spaying SA every day had the best effect.These findings would provide a basis for the further exploration of Helianthus tuberosus in ClO4-contaminated soil.