中文摘要：

以谷子（Setaria italica（L.）Beauv.）为研究材料,从拔节期开始持续浇灌1.88、15mmol·L^-12种氮供应水平营养液,从抽穗期开始对材料进行增强UV-B辐射处理（14.7μW·cm^-2）,研究了谷子叶片中总叶绿素、可溶性物质及紫外吸收物质的含量在开花期期间的变化。结果表明：与较高氮供应水平相比,无论是否进行增强UV-B辐射,较低氮供应水平明显降低了谷子叶中总叶绿素、可溶性蛋白的含量,但提高了其紫外吸收物质的含量;与较低氮供应水平相比,较高氮供应水平下的谷子叶中总叶绿素含量在开花期初期和中期,可溶性蛋白含量在开花期中期对增强UV-B辐射处理更敏感;氮供应水平虽然对开花期中期至末期的谷子叶片可溶性糖含量有显著影响,但在整个增强UV-B辐射处理期间,该指标对增强UV-B辐射并不敏感。上述结果表明,较低氮供应水平可促进谷子叶片在开花期期间紫外吸收物质的积累,有利于增强其抵抗UV-B辐射能力,但仍应寻求一个合理范围的氮供应水平,以平衡谷子生殖生长和提高对UV-B辐射抗性的需求。

英文摘要：

The aim of the present study is to investigate the responses of the contents of leaf chlorophyll,soluble substances and UV-B absorbing compounds of foxtail millet（ Setaria italica（ L.）Beauv.） at flowering stage to enhanced UV-B radiation treatment and whether the possible effect varied with nitrogen supply. The plants of foxtail millet were fertilized at two different nitrogen supply levels（ 1.88 and 15 mmol·L……-1） from the beginning of jointing stage and stressed by an enhanced UV-B radiation treatment（ 14.7 μW·cm-2） from the beginning of heading stage. The results showed that chlorophyll content and soluble protein content decreased evidently,while UV-B absorbing compounds content increased in leaves of foxtail millet under the lower nitrogen supply level compared to the group under the higher nitrogen supply level during the treatment period,with or without enhanced UV-B radiation. Chlorophyll content from the beginning to middle of flowering stage and soluble protein content at the beginning of flowering stage in leaves of foxtail millet under the higher nitrogen supply level were more sensitive to the enhanced UV-B radiation treatment than under the lower nitrogen supply level. Leaf soluble sugar content was not sensitive to the enhanced UV-B radiation treatment,whereas it was significantly affected by nitrogen supply level from the middle to the end of flowering stage. The study indicated that the lower nitrogen supply level could improve the resistance of plants against UV-B radiation by promoting the accumulation of UV-B absorbing compounds in leaves of foxtail millet at flowering stage; however,a reasonable range of nitrogen supply level should be adopted to balance the requirements between reproductive growth and improvement of the resistance to UV-B radiation.