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通过分根培养的方法,用聚乙二醇(PEG6000)模拟水分胁迫,研究3种氮形态(NO 3--N,NH 4+-N,50%NO 3--N+50%NH 4+-N)及其供应部位对局部根区水分胁迫下玉米生长的影响。水分胁迫处理16d后,测定叶绿素荧光参数及茎、叶、根形态指标。结果发现,同一氮形态下,水氮同区处理(氮供应在非水分胁迫一侧)比水氮异区(氮供应在水分胁迫一侧)更有利于玉米植株的生长;水氮同区处理下光能利用与转化效率较高,半饱和光强(Ik)增加;根、茎、叶长势良好;水氮异区处理下,植株生长减缓。在不同的氮形态比较中,混合氮有利于促进植株生长,Yield、ETR、qP、ETRm、Ik较高。PSⅡ最大光化学效率(Fv/Fm)和PSⅡ潜在活性(Fv/Fo)在水氮同区处理中,呈随着混合氮、硝态氮、铵态氮减低的趋势。
The three nitrogen forms (NO 3 - N, NH 4 + -N, 50% NO 3 - N + 50% NH 4+) were studied by rooting culture with polyethylene glycol (PEG 6000) -N) and its supplying parts on the growth of maize under local root zone water stress. After 16 days of water stress treatment, the chlorophyll fluorescence parameters and the morphological indexes of stem, leaf and root were measured. The results showed that under the same nitrogen form, the same treatment of water and nitrogen (nitrogen supply on the non-water stress side) was more beneficial to the growth of maize than that of water and nitrogen (nitrogen supply on the water stress side) The light utilization and transformation efficiency were higher, and the half-saturation light intensity (Ik) increased. The growth of roots, stems and leaves was good. Under different water-nitrogen treatments, plant growth was slowed down. In the comparison of different nitrogen forms, mixed nitrogen was beneficial to plant growth, Yield, ETR, qP, ETRm, Ik higher. The maximum photochemical efficiency of PSⅡ (Fv / Fm) and the potential activity of PSⅡ (Fv / Fo) tended to decrease with the mixed nitrogen, nitrate nitrogen and ammonium nitrogen in the same treatment of water and nitrogen.