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本研究以优质高产甘蓝型油菜(湘农油571)为试验材料,通过苗期土培和溶液培养试验,分析了硫肥对外源施硒条件下土壤硒赋存形态和硒价态变化的影响,旨在揭示硫调控油菜硒吸收的作用机制.结果表明,5 mg·kg-1硒和150 mg·kg-1硫对油菜生长都有一定的促进作用,但这种促进都没有达到显著水平;施硫可以显著降低油菜地上部和根的硒含量,最高降幅分别为64.0%和39.1%;施硫可以显著降低土壤pH值,最高可降低0.65个单位,显著增加土壤有机质含量,最高可增加1.76 g·kg-1;施硫可以显著降低水溶态硒和铁锰氧化物结合态硒含量并显著增加有机结合态硒含量,而对交换态和残渣态硒含量的影响不显著;施硫可以显著降低水溶态并显著增加交换态中四价硒的含量,对这两种形态中的六价硒含量都表现为显著的降低作用,对负二价硒含量没有显著的影响;油菜对两种硒价态的吸收差异与硫密切相关,无硫时,六价硒处理的苗期油菜地上部和根的硒含量为四价硒处理的7.3倍和3.2倍,而硫浓度为2 mmol·L-1时,其硒含量却不及四价硒处理的32.6%和8.7%.总体上,施用适量硫肥在改善作物生长的同时可以通过降低土壤pH值和提高有机质含量促使水溶态硒在土壤中向铁锰氧化物结合态和有机结合态的钝化并抑制硒向六价态的转化来降低油菜对硒的吸收,对合理调控富硒地区作物硒含量,保证我国居民饮食质量和安全、土壤硒资源长效利用及区域经济发展具有重要意义.
In this study, high-quality and high-yielding Brassica napus (Hunan Agricultural Oil 571) as the material, through the soil culture and solution culture experiments at seedling stage, the effects of sulfur fertilizer on the distribution of selenium and selenium in soil under external application of selenium In order to reveal the mechanism of sulfur regulation of selenium uptake in rapeseed.The results showed that 5 mg · kg -1 selenium and 150 mg · kg -1 sulfur promoted the growth of rapeseed but did not reach significant level ; Applying sulfur can significantly reduce the selenium content in shoots and roots of rapeseed with the maximum decrease of 64.0% and 39.1%, respectively. Applying sulfur can significantly reduce the soil pH by a maximum of 0.65 units, increase the content of soil organic matter significantly and increase the maximum 1.76 g · kg-1. Sulfur application could significantly reduce the content of selenium and iron-manganese oxide bound selenium and significantly increase the content of organic bound selenium, but had no significant effect on exchangeable and residual selenium contents. Significantly reduce the water-soluble state and significantly increase the exchangeable tetravalent selenium content of both forms of hexavalent selenium content showed a significant reduction, negatively bivalent selenium content had no significant effect; rape pairs of two Absorption difference of selenium valence It is closely related to sulfur. When sulfur-free, the selenium content of shoots and roots in seedlings of hexavalent-selenium was 7.3 times and 3.2 times higher than that of tetravalent selenium treatments, respectively. When the concentration of sulfur was 2 mmol·L-1, The content was less than 32.6% and 8.7% of selenium-selenium treatment.In general, the application of proper amount of sulfur fertilizer could improve the growth of crops and promote the dissolution of water-soluble selenium into Fe-Mn oxide in the soil by reducing soil pH and increasing the content of organic matter State and organic combination of passivation and inhibition of selenium into the hexavalent state to reduce the absorption of selenium rapeseed, selenium content of crops in the selenium content regulation, to ensure that our residents diet quality and safety, long-term use of soil selenium resources and Regional economic development is of great significance.