水分胁迫下玉米幼苗对外源原儿茶醛的生理响应

以玉米(Zea may L.)品种"郑单958"为材料,采用0.15 g.mL-1聚乙二醇(PEG-6000)模拟水分胁迫,研究外源原儿茶醛根施预处理对玉米幼苗叶片相对含水量(RWC)、活性氧代谢系统、抗氧化酶类以及渗透调节物含量的影响。结果表明,0.15 g.mL-1PEG-6000胁迫16 h,玉米叶片的活性氧代谢系统(丙二醛含量、细胞膜透性、超氧阴离子自由基水平)、超氧化物歧化酶(SOD)与过氧化物酶(POD)活性、以及主要渗透调节物(可溶性蛋白、可溶性糖)均极显著升高,而RWC、抗坏血酸过氧化物酶(APX)活性极显著降低;原儿茶醛(0.5~25 mg.L-1)预处理可极显著抑制水分胁迫下玉米幼苗叶片活性氧代谢系统以及渗透调节物含量的上升,并诱导SOD、POD和APX等抗氧化酶类活性提高,提高叶片RWC。说明原儿茶醛能够提高玉米幼苗的抗氧化能力,减少水分胁迫诱导的活性氧自由基积累,缓解膜脂过氧化,有效增强植株抗水分胁迫的能力。

Physiological Responses of Maize Seedlings to the Exogenous Protocatechuic Aldehyde Pretreatment under Water Stress

This paper was studied to understand the physiological responses of maize seedlings to the exogenous protocatechuic aldehyde(PCA)pretreated under water stress.Zea may L.cultivar,"Zhengdan 958" was used for the experiments.The seedlings of maize were pretreated by exogenous protocatechuic aldehyde for three days,and then were transferred to a solution with 0.15 g·mL-1 PEG-6000 for water stress treatment.After 16 h,the leaves of the seedlings were used for the measurements of the relative water content RWC,active oxygen metabolism system(malondialdehyde(MDA) content,cell membrane permeability,O2-· level),antioxidant enzyme activities(superoxide dismutase(SOD),peroxidase(POD),ascorbate peroxidase(APX))and the contents of major osmoregulation substances(soluble protein,soluble sugar contents).The results showed that(1) The 0.15 g·mL-1 PEG-6000 treatment led to significant improvement of active oxygen metabolism system,SOD、POD activity and major osmoregulation substance while RWC level,and APX activity decreased significantly in the leaves of maize.(2) The pretreatment of protocatechuic aldehyde(0.5-25 mg·L-1) alleviated the events of water stress induced in the leaves and increased RWC level、the activities of antioxidant enzymes such as SOD,POD and APX.It suggested that the root application of exogenous protocatechuic aldehyde could improve the antioxidative ability of maize seedlings and thus are advantageous to the resistance of plants to water stress.