控释碘肥对生菜富碘及若干生理特性的影响

Effects of controlled-release iodine fertilizers on iodine accumulation and some physiological characteristics of lettuce

通过温室盆栽试验,以普通碘肥为对照,研究了包膜控释碘肥对生菜富碘及某些生理特性的影响。结果表明,施碘处理与不施碘相比显著提高生菜叶片的碘含量。在两种施碘水平下(I 10和20 mg/kg,土),与普通碘肥相比,控释碘酸钾和控释碘化钾均显著提高生菜叶片的碘含量,分别提高了46.60%～61.16%、46.59%～58.53%;同时提高了生菜生物量、叶片叶绿素含量、维生素C含量及抗氧化酶活性[超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)],降低了生菜叶片硝态氮和丙二醛(MDA)含量;碘酸根离子处理的土壤碘的淋失率高于碘离子处理;施用控释碘酸钾和控释碘化钾后,土壤淋溶液中碘淋失量峰值出现时间延后,碘淋失率较普通碘肥分别降低了45.99%～50.97%、39.18%～46.29%,差异显著。碘肥用量试验的结果表明,与施碘10mg/kg相比,施碘20 mg/kg时显著提高了生菜叶片的碘含量,但对生菜品质及生理指标无显著影响。与普通碘肥相比,控释碘肥不仅显著提高了生菜叶片对碘的富集,还减少了碘素从土壤中的流失量,提高了碘肥的利用率。施用控释碘肥是培育富碘蔬菜的有效途径之一。

A greenhouse pot experiment was conducted to assess the effects of controlledrelease iodine fertilizers on the iodine accumulation and physiological response of lettuce in comparison with traditional iodine fertilizers. The plants were subjected to different iodine fertilizers containing two levels of iodine as iodate or iodide, 10 and 20 mg/kg soil. The results show that all the treatments with iodine applied significantly increase the iodine contents in leaves of lettuce. The leaf iodine contents developed from the controlledrelease potassium iodate and the controlledrelease potassium iodide are significantly enhanced by 46.60%-61.16% and 46.59%-58.53% in comparison with the corresponding traditional iodine fertilizers, respectively. The biomass amounts （fresh mass and dry mass of shoot and root） and leaf chlorophyll contents of lettuce grown with the controlledrelease iodine fertilizers are higher than those of the traditional iodine fertilizers. The growthpromoting function is also associated with the increases of vitamin C and activities of superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT） in lettuce leaves. Application of the controlledrelease iodine fertilizers results in the reduced NO-3-N content and diminished lipid peroxidation （MDA） content of lettuce leaves. Amount of iodine in leachate peaked with controlledrelease iodine fertilizers are higher than those of the traditional iodine fertilizers. The controlledrelease potassium iodate and the controlledrelease potassium iodide also significantly reduce the iodine leached rates by 45.99%-50.97% and 39.18%-46.29% compared to the traditional fertilizers, respectively. When iodine applied rate is 20 mg/kg soil, the leaf iodine content is significantly higher than that of the 10 mg/kg soil, while no significant differences are found in other indexes. Overall, the controlledrelease iodine fertilizers increase iodine accumulation in lettuce leaves, prevent iodine leaching and improve iodine use efficiency, and are proven to be the optimum for cultivating iodineenriched vegetables.