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采用盆栽控水试验,研究干旱胁迫下氮肥水平对玉米光合作用及保护酶活性的生理响应。结果表明,与正常灌水处理相比,干旱胁迫降低玉米叶片的气孔导度(Gs)、蒸腾速率(Tr)、PSⅡ最大光化学效率(Fv/Fm)、PSⅡ量子产量(φPSⅡ)和光化学猝灭系数(qP);增加胞间CO2浓度(Ci)、非光化学猝灭系数(qN)和丙二醛(MDA)含量;保护酶活性(SOD、POD和CAT)升高。干旱胁迫下适量施氮(225 kg/hm2)提高玉米叶片的Gs、Tr、Fv/Fm、φPSⅡ和qP;降低Ci和qN;同时显著提高保护酶活性(SOD、POD和CAT),降低膜质过氧化程度,全面改善叶片光合功能和内在的生理特性。不施氮肥和过量施氮(450 kg/hm2)均表现出与适量施氮处理相反的变化趋势。
The pot experiment was conducted to study the physiological responses of photosynthesis and protective enzyme activity to nitrogen stress in maize under drought stress. The results showed that compared with the normal irrigation treatments, the drought stress reduced the stomatal conductance (Gs), transpiration rate (Tr), maximum photochemical efficiency of PSⅡ (Fv / Fm), PSⅡ quantum yield (φPSⅡ) and photochemical quenching (qP), increase of intercellular CO2 concentration (Ci), non-photochemical quenching coefficient (qN) and malondialdehyde (MDA) content. The activity of protective enzymes (SOD, POD and CAT) increased. Nitrogen (225 kg / hm2) increased the Gs, Tr, Fv / Fm, φPSⅡ and qP of maize leaves under drought stress and decreased Ci and qN, while significantly increased the activity of protective enzymes (SOD, POD and CAT) Peroxidation, to improve the photosynthetic function and intrinsic physiological characteristics of leaves. No nitrogen fertilizer and excess nitrogen (450 kg / hm2) showed the opposite trend with the amount of nitrogen treatment.