【摘要】 研究了生长在1.875 mmol.L-1和15 mmol.L-1硝态氮素水平条件下的谷子(Setaria italica(L.)Beauv.)开花期间在进行强度为7.12 kJ.m-.2d-1增强UV-B辐射处理时叶片类黄酮含量、苯丙氨酸解氨酶(PAL)和保护酶活性变化差异。主要结果表明在开花期无论是否进行增强UV-B辐射处理,较低水平氮素均比较高水平氮素更有利于提高谷子叶片PAL活性;叶片类黄酮含量除在进行增强UV-B处理时较低氮素条件下生长的谷子在开花末期显著高于较高氮素条件下生长的谷子外,受氮素水平影响不甚明显。而在开花期不进行与进行增强UV-B辐射处理,氮素水平对叶片保护酶的影响有所差异:不进行增强UV-B辐射处理,整个开花期氮素水平对谷子叶片SOD活性有显著影响而对ASP活性无显著影响,对CAT和POD活性则在开花期部分阶段有显著影响。进行增强UV-B辐射处理,整个开花期氮素水平对谷子叶片SOD与CAT活性有显著影响而对ASP、POD活性影响不显著。更多还原

【Abstract】 The purpose of this study was to investigate the effects of different nitrogen conditions on anti-UV-B matter and protective enzymes in leaves of the millet plant in the florescence period.Potted millet(Setaria italica(L.) Beauv.) plants grown outdoors,under 1.875 mmol·L-1 and 15 mmol·L-1 nitrogen respectively,were exposed to enhanced UV-B radiation(7.12 kJ·m2·d-1) for experimentation.Determined were the contents of flavonoids,activities of phenylalanine ammonia-lyase(PAL),ascorbate peroxidase(ASP),catalase(CAT),peroxidase(POD) and superoxide dismutase(SOD).PAL activity in leaves of millet plants grown under the lower nitrogen condition was increased significantly compared to that under the higher nitrogen condition.Contents of flavonoids in leaves of millet plants had no significant difference between the lower and higher nitrogen conditions during the period of florescence,no matter whether exposed to enhanced UV-B radiation or not,except that a significant increase occurred in the content of flavonoids when under the lower nitrogen condition and enhanced UV-B radiation during the end of florescence.These results suggested that no matter whether the treatment of enhanced UVB radiation was imposed or not in the florescence period,different nitrogen conditions evidently did not affect the content of flavonoids in millet leaves,although the lower nitrogen condition was more favorable to improved PAL activity in millet leaves than was the higher nitrogen condition.Furthermore,in leaves of millet plants grown under the lower nitrogen condition,SOD activity was increased significantly all the time;CAT activity was decreased significantly only in the mid-term of the florescence period;POD activity was increased significantly only in the early and the late florescence period;and,ASP activity was not increased significantly compared to that under the higher nitrogen condition unless exposed to enhanced UV-B radiation during the whole florescence period.Meanwhile,with exposure to enhanced UV-B radiation in the florescence period,CAT activity was decreased while SOD activity was increased,both significantly,in leaves of millet plants grown under the lower nitrogen condition compared to those under the higher nitrogen condition.However,ASP and POD activities had no significant difference in leaves of millet plants grown under either the lower or higher nitrogen conditions.Thus,the results implied that the effects of different nitrogen conditions on protective enzymes in millet leaves were limited during the florescence period,especially under conditions of exposure to enhanced UV-B radiation.更多还原