外源抗坏血酸对铜胁迫菊苣幼苗生长的缓解效应

为探究外源抗坏血酸(AsA)对铜(Cu)胁迫下菊苣幼苗生长的缓解效应,本研究以普那菊苣为试验材料,采用溶液培养法研究外源AsA对50μmol·L^-1Cu胁迫下菊苣幼苗的生长、Cu积累和生理特性的影响。结果表明,50μmol·L^-1Cu胁迫严重抑制了菊苣幼苗的叶绿素含量、光合作用和生物量的积累,加剧了细胞膜脂质过氧化程度,降低了抗氧化酶(SOD、POD、CAT、APX)活性以及可溶性蛋白含量。外源AsA降低了根系对Cu的吸收和转运,缓解了Cu胁迫对菊苣幼苗的伤害,具体表现为根系、茎叶及总干物质量提高;减少了光合色素(叶绿素a、叶绿素b、总叶绿素以及类胡萝卜素)的降解,提高了光合作用参数;降低脂质过氧化对细胞膜的损伤;提高了抗氧化酶活性、可溶性蛋白含量以及内源AsA含量。总之,外源AsA通过提高Cu胁迫下菊苣幼苗光合作用特征、抗氧化酶活性和渗透调节物质的含量,缓解了Cu胁迫对菊苣幼苗生长的毒害作用。该结果为外源AsA应用于缓解植物Cu毒害及丰富菊苣耐Cu机制提供依据。

Mitigative effect of exogenous ascorbic acid on the growth of copper-stressed chicory (Cichorium intybus)seedlings

This research explored the mitigative effect of exogenously applied ascorbic acid(AsA)on the growth,Cu accumulation and physiological characteristics of chicory(Cichorium intybus)seedlings under copper stress(Custress).Cu-stress was achieved by growing seedlings in hydproponic culture with 50μmol·L^-1 Cu²⁺added to the culture solution.It was found that Cu-stress at 50μmol·L^-1 severely suppressed the chlorophyll content,and photosynthesis and biomass accumulation of the chicory seedlings.Cu-stress also increased the degree of cell membrane lipid peroxidation,and reduced soluble protein contents and the antioxidant activities of superoxide dismutase,peroxidase,catalase and ascorbate peroxidase.In contrast,exogenous AsA decreased the absorption and transport of Cu by the root system and ameliorated the damage of Cu-stress to chicory seedlings.Specifically,exogenous AsA increased the root system,shoot and total dry matter biomass,decreased the degradation of photosynthetic pigments(chlorophyll a,chlorophyll b,total chlorophyll,and carotenoid)and enhanced the photosynthetic parameters,reduced the damage of lipid peroxidation to the cell membrane,and enhanced the antioxidant activities,soluble protein levels and endogenous AsA concentration.These results provide reference data for the application of exogenous AsA in mitigating Cu toxicity to plants and enhancement of the Cu tolerance mechanism of chicory.