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采用温室砂培试验,研究了不同浓度砷(As)处理对玉米郑单958幼苗生物量积累、光合色素含量、抗氧化系统、As及矿质离子吸收、分布的影响.结果表明:低浓度(<2mg·L-1)的As刺激了玉米幼苗的生长,植株株高、主根长和生物量积累均显著增加;高浓度(>4mg·L-1)As严重抑制了玉米幼苗生长.2mg·L-1As处理下,叶绿素a、叶绿素b和叶绿素a+b含量均达到峰值;随As处理浓度增加,叶绿素含量逐渐下降;电镜观察发现,10mg·L-1As处理下,叶片叶绿体结构遭到破坏,类囊体膜溶解.根系3种抗氧化酶(SOD、POD、CAT)活性均随As浓度增加而增大;叶片3种抗氧化酶活性在8mg·L-1出现峰值,且对As处理的敏感性表现为POD>CAT>SOD.MDA、可溶性糖和可溶性蛋白含量与As浓度呈正相关.高浓度的As明显抑制了P、K、Ca、Fe等元素的吸收.根系对As胁迫的反应比地上部更为敏感,因此根系生长发育指标更适合作为植物As毒害的指示指标.
The effects of arsenic (As) treatment on the biomass accumulation, photosynthetic pigment content, antioxidant system, As and mineral ion absorption and distribution in the seedlings of Zhengdan 958 were studied by greenhouse sand culture experiment.The results showed that: low concentration (< 2mg · L-1) As stimulated the growth of maize seedlings, the plant height, main root length and biomass accumulation increased significantly. High concentration (> 4mg · L-1) As inhibited the growth of maize seedlings seriously. -1As treatment, the content of chlorophyll a, chlorophyll b and chlorophyll a + b peaked. With the increase of As concentration, the content of chlorophyll decreased gradually. Under electron microscope, the chloroplast structure was damaged under 10 mg · L-1As treatment, Thylakoid membrane lysis. The activities of three antioxidant enzymes (SOD, POD and CAT) in roots increased with the increase of As concentration. The activities of three antioxidant enzymes in leaves were peaked at 8 mg · L -1, Sensitivity showed POD> CAT> SOD.MDA, soluble sugar and soluble protein content positively correlated with As concentration.As high concentration As significantly inhibited the absorption of P, K, Ca, Fe and other elements.The root response to As stress Aboveground is more sensitive, so root growth and development indicators more suitable as a plant As poison Indicators of harm.