Effects of Nitrogen Fertilizer Level on Chlorophyll Fluorescence Characteristics in Flag Leaf of Super Hybrid Rice at Late Growth Stage

摘要

To compare the effects of slow-release nitrogen fertilizer at six different levels on the flag leaf chlorophyll fluorescence characteristics of super hybrid rice,a field fertilization experiment was conducted with super hybrid rice Y Liangyou 1 as a test material.The photosynthetic electron transport rate (ETR),effective quantum yield (EQY),photochemical quenching coefficient (q P),and non-photochemical quenching coefficient (NPQ) of flag leaves were measured at the initial heading,full heading,10 d after full heading and 20 d after full heading stages.Results showed that the values of ETR,EQY and q P increased with rice development from initial heading to 20 d after full heading,whereas the NPQ decreased.During the measured stages,ETR,EQY and q P increased initially and then decreased as nitrogen application amount increased,but they peaked at different nitrogen fertilizer levels.The maximum ETR and EQY values appeared at the treatment of 135 kg/hm 2 N.In conclusion,the optimum nitrogen amount for chlorophyll fluorescence characteristics of super hybrid rice was 135 180 kg/hm 2.