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光合速率在日出后随着光强的增强而急速升高,4月20日是小麦光合最强。净光合速率日变化随施氮量的增加而下降,水胁迫处理显著低于高水处理;不同时段变化净光合速率随施氮量和土壤含水量的增加而增加,但总的趋势是降低的。小麦蒸腾速率日变化总体趋势是在日出后随着光强的增强而急速升高、随光强的减弱而降低。小麦蒸腾速率日变化曲线为单峰型,中午最高。叶片蒸腾速率日变化随土壤水分供应增加而增加,随氮肥供应增加而下降;不同供水供氮条件下,叶片蒸腾速率的分异在日中尤其是上午比较明显。蒸腾速率从4月10日一直呈现下降趋势。小麦叶片水分利用率日变化曲线为“L”型,即早上较高,中午和下午都非常低。4月20日叶片水分利用率最高,5月10日最低。叶片对不同土壤水分和氮控制的反映为高氮低水高水分利用率,反之,则水分利用率较低。不同水、氮在上午对叶片水分利用率影响差异比较明显,下午则趋于一致。
Photosynthesis rate rises rapidly with the increase of light intensity after sunrise, April 20 is the strongest of photosynthesis in wheat. The diurnal variation of net photosynthetic rate decreased with the increase of nitrogen application rate, and the water stress treatment was significantly lower than that of high water treatment. The net photosynthetic rate of net photosynthesis increased with the increase of nitrogen application rate and soil water content, but the general trend was decreased . The general trend of diurnal variation of transpiration rate of wheat is that it increases rapidly with the increase of light intensity after sunrise and decreases with the decrease of light intensity. The daily variation of transpiration rate of wheat was unimodal and highest at noon. The diurnal variation of leaf transpiration rate increased with the increase of soil water supply and decreased with the supply of nitrogen fertilizer. The differentiation of leaf transpiration rate under different water and nitrogen supply conditions was more obvious in the morning, especially in the morning. Transpiration rate from April 10 has been showing a downward trend. The daily variation of water use efficiency of wheat leaves was “L”, which was higher in the morning and very low in the afternoon and afternoon. April 20 leaves the highest water use efficiency, the lowest on May 10. The control of leaf moisture on different soil moisture and nitrogen reflect the high water use efficiency of high nitrogen and low water, otherwise, the water use efficiency is low. Different water, nitrogen in the morning on the water use efficiency of leaves more obvious differences, the afternoon tends to be the same.