In order to explore the effect of water and fertilizer on photosynthetic characteristics of different wheat varieties ,the net photosynthetic rate ,transpiration rate and instantaneous water use efficiency of Aikang 58 and Zhoumai 18 were measured at jointing stage ,anthesis stage and grain-filling stage under different water and fertilizer conditions in loam alluvial soil in Tongxu county .The water conditions included no irrigation ,mild drought stress and full irrigation ,the times of nitrogen fertilizer topdressing included zero ,once(reviving to jointing stage )and twice (jointing and grain filling stage) .The results showed that the photosynthetic rate of two wheat varieties increased with the growth of wheat ,and the treatment with additional fertilizer at join-ting and grain filling stage under mild drought stress was beneficial to improve photosynthetic rate compared with other treatments ,especially Aikang 58 .The effect of different water and fertilizer conditions on transpiration rate of Zhoumai 18 at different growth stage was greater than that on Aikang 58 .At jointing stage ,the transpiration rate of the treatment with additional fertilizer at jointing and grain filling stage under mild drought stress was the lowest for Zhoumai 18 ,while it was lower for Aikang 58 .At flowering stage ,the highest one of the transpiration rate for two wheat varieties was the treatment with additional fertilizer at reviving to jointing stage without ir-rigation ,and the second was the treatment with additional fertilizer at jointing and grain filling stage under mild drought stress ,the treatment without topdressing with full irrigation was lowest for Zhoumai 18 ,while the treatment without topdressing under mild drought stress was lowest for Ankang 58 .At grain filling stage ,the highest one of the transpiration rate for two wheat varieties was the treatment without topdressing and irrigation ,the lowest one was the treatment without topdressing and the treatment with additional fertilizer at reviving to jointing stage under mild drought stress .The instantaneous water use efficiency of two wheat varieties first decreased and then increased with the growth of wheat ,but the increase range was different ,which of Zhoumai 18 was greater than Aikang 58 .In a word ,mild drought stress was conducive to improve the net photosynthetic rate and instantaneous water use efficiency ,and decrease transpiration rate ,espe-cially the treatment with additional fertilizer at join-ting and grain filling stage ,and the photosyn-thetic capacity of Zhoumai 18 was higher than Aikang 58 .%为探明水肥条件对不同小麦品种光合特性的影响，在通许县壤质潮土不同水分（不灌水、轻度干旱胁迫、充分灌溉）和氮肥追施次数（不追肥、返青-拔节期追肥、拔节期追肥＋灌浆期追肥）条件下分析了不同小麦品种（矮抗58和周麦18）在拔节期、扬花期和灌浆期的净光合速率、蒸腾速率、叶片瞬时水分利用效率。结果表明：2个小麦品种的净光合速率总体均随小麦生育期的推进而提高，增加幅度均以轻度干旱胁迫拔节期追肥＋灌浆期追肥处理最大，尤其是矮抗58。水肥处理对周麦18不同生育时期的蒸腾速率影响较大，而对矮抗58影响较小。拔节期，周麦18蒸腾速率以轻度干旱胁迫拔节期追肥＋灌浆期追肥处理最低，矮抗58蒸腾速率以该处理较低；扬花期，2个小麦品种蒸腾速率均以不灌水返青-拔节期追肥处理最高，周麦18以充分灌溉不追肥处理最低，矮抗58以轻度干旱胁迫不追肥处理最低，两品种均以轻度干旱胁迫拔节期追肥＋灌浆期追肥处理次之；灌浆期，从2个小麦品种蒸腾速率平均值来看，蒸腾速率以不灌水不追肥处理最高，轻度干旱胁迫不追肥处理和轻度干旱胁迫返青-拔节期追肥处理最低。2个小麦品种叶片瞬时水分利用效率均随生育期推进先降低后升高，但升高幅度不同，周麦18高于矮抗58，2个品种总体以轻度干旱胁迫条件下更利于小麦叶片瞬时水分利用效率的提高，尤其是拔节期追肥＋灌浆期追肥处理。总之，轻度干旱胁迫有利于提高小麦蒸腾速率、降低蒸腾速率、提高叶片瞬时水分利用效率，尤其是拔节期追肥＋灌浆期追肥处理，且周麦18光合利用能力高于矮抗58。
展开▼
