外源水杨酸改善Cd胁迫下路易斯安娜鸢尾的生长和养分吸收

Improvement on the growth and nutrient absorption of Iris hexagona by exogenous salicylic acid under Cd stress

采用Hoagland溶液培养,研究了外源水杨酸(SA)预处理对镉(Cd)胁迫下路易斯安娜鸢尾生物量、含水量、光合作用、根系活力、Cd积累、矿质养分吸收和抗氧化酶活性的影响.结果表明:Cd胁迫下,SA预处理的植株根叶干质量、根系活力和净光合速率提高.与单独Cd处理相比,SA预处理后的胁迫植株Cd含量无明显变化,而叶片N、P、S含量显著提高,K含量显著下降,根部抗氧化酶活性显著提高.表明SA预处理可明显缓解路易斯安娜鸢尾的Cd伤害,其原因不在于减少Cd吸收量而是提高了对Cd的抗性,矿质元素的吸收积累调节和根部抗氧化酶活性的提高是其毒害缓解的重要原因.

The effects of exogenous salicylic acid（ SA） pretreatment on the biomass,water content,photosynthesis,root vigor,Cd accumulation,nutrient absorption and antioxidant enzyme activity of Iris hexagona under Cd stress were studied by using Hoagland solution culture. The results showed that SA pretreatment promoted dry mass,root vigor and net photosynthetic rate of Cdstressed I. hexagona seedlings. Compared with only Cd treatment,the Cd accumulation of Cd-treated plants with SA pretreatment remained unaffected,however,SA pretreatment increased contents of N,P,S,and decreased K content. Activities of antioxidant enzymes of Cd-treated seedling root were increased under SA pretreatment. In conclusion,the improvement on growth of I. hexagona by SA pretreatment under Cd stress was attributed to improving Cd tolerance rather than reducing Cd uptake. The regulation of mineral element accumulation and the increase of antioxidant enzyme activities could be explained for Cd resistance improvement induced by salicylic acid.