不同耕作方式与氮肥类型对夏玉米光合性能的影响

Effects of Tillage Methods and Nitrogen Fertilizer Types on Photosynthetic Performance of Summer Maize

为了探讨不同耕作方式与氮肥类型对夏玉米光合性能的影响及其作用机制,本试验以玉米杂交种郑单958为供试材料,通过快速叶绿素荧光诱导动力学曲线(OJIP)及820 nm光吸收等技术,深入研究了玉米花后叶片叶绿素含量、含氮量、气体交换参数、光系统II(PSII)、光系统I(PSI)及二者间的协调性。两年研究结果表明,与常规尿素相比,施用控释尿素均可显著提高玉米花后穗位叶叶绿素含量、净光合速率(Pn)及后期气孔导度(Gs),明显改善光系统间协调性。与旋耕相比,深松可进一步加强施氮对玉米叶片光合性能的促进作用。控释尿素结合深松可显著提高叶绿素含量及Pn,明显改善叶片PSII反应中心供体侧和受体侧性能,增强电子由PSII向PSI的传递,使花后叶片PSII与PSI间协调性显著增加,有利于产量形成期光合性能稳定。光合性能的提高显著增加了穗粒数和单株籽粒产量,最终提高玉米产量。因此,深松与控释尿素结合可有效地协调PSII与PSI,提高夏玉米光合性能,促进玉米增产。

In order to understand the effects of different tillage methods and nitrogen fertilizer types on photosynthetic performancesand their mechanism,the characteristics of photosystem II(PSII),photosystem I(PSI)and the coordination between them inear leaves of maize(cultivar,Zhengdan958)were studied by using fast chlorophyll fluorescence-induction kinetics and820nmlight-absorption curves.Two-year field experiment indicated that,compared with normal urea,controlled-release urea significantlyincreased the chlorophyll content,net photosynthetic rate(Pn)and stomatal conductance(Gs)of ear leaves after anthesis,and significantly improved the coordination between PSII and PSI.Compared with rotary tillage,subsoiling significantly increasedthe photosynthetic performances in ear leaves during reproductive stage.Subsoiling method combined with controlled-release urea application could significantly increase chlorophyll content,improve the performances of electron donor andacceptor sides of electron transport chain in PSII reaction center,and enhance the distribution of electron transported from PSII toPSI as well.Consequently,the coordination between PSII and PSI after anthesis was significantly improved,which is conduciveto the stability of photosynthetic performances during maize reproductive stage.The improvement of photosynthetic performances under subsoiling method and controlled-release urea treatment significantly enhanced Pn in ear leaves and increased grain numberper ear and grain yield per plant,and eventually increased maize yield.Therefore,subsoiling combined with controlled-releaseurea could effectively improve photosynthetic performances by increasing the coordination between PSII and PSI,which is themajor reason for increasing maize yield.