氟污染对玉米幼苗生长及生理特性的影响

为探讨氟污染对农作物的影响，以玉米为供试材料，采用砂基培养的方法，研究了不同浓度的氟（F）对玉米幼苗形态、生物量、光合参数、叶绿素含量、抗氧化酶活力以及丙二醛含量的影响。结果表明，与对照相比，低浓度 F（≤0.25 mmol·L^-1）对玉米幼苗生长无明显抑制现象；随着溶液中F浓度的增加，玉米幼苗生长显著受到抑制，叶长、株高生长变慢，叶面积减小；根系和地上部干物质积累下降；叶片中叶绿素合成受阻，光合速率降低；同时丙二醛（MDA）含量增加；过氧化物酶（POD）活性明显升高，而超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性均表现出一定的下降趋势。说明氟的存在不利于植物的正常生长，研究结果还为进一步揭示氟污染机理以及氟污染的综合治理提供了理论依据。

Effects of Fluoride Pollution on the Growth and Physiological Characteristics of Maize Seedlings

Fluoride （F）, a common phytotoxic air, water and soil pollutant is commonly released to the environment by a number of industrial processes. The maize was used as an experimental material and the effects of different concentrations of fluoride（0, 0.25, 0.5, 5, 10 mmol·L^-1） on the growth and physiological characteristics of maize seedlings were studied using sand cultivation, the plant modality, biomass, parameters of photosynthesis, chlorophyll contents, activities of three anti-oxidative enzymes and malondialdehyde（MDA） contents were all determined. The results were as follows：contrasting to the control of maize seedlings without F, when the F concentration was lower than 0.25 mmol ·L^-1, the growth of seedlings was stimulated. With the increase of F concentration, the seedling growth was obviously restrained, that was, the leaf length and plant height slowed down markedly, the leaf area reduced, the root/shoot dry weight accumulation decreased and the chlorophyll synthesis in leaves was inhibited and the photosynthesis rate decreased as well. On the other hand, the MDA content and the peroxidase （POD） activities increased while superoxide dismutase （SOD） and catalase （CAT） activities decreased under higher F concentration. The results indicated that the high F concentration was not conducive to the growth of maize seedlings, it also provided theoretical basis for probing into physiological mechanism of fluoride pollution and its comprehensive controlling.