Effect of Nitrogen Fertilization On Photosynthetic Performance of Ear Leaves in Different Stay-Green Maize Inbred Lines at Grain-Filling Stage.

Abstract: At grain filling stage, the regulatory mechanisms of nitrogen fertilization on photosynthetic performance of stay-green maize inbred line Qi 319 (Q319) and non-stay-green maize inbred line HuangZao 4 (HZ4) were studied. Fast chlorophyll fluorescence induction kinetics curve and 820 nm light absorption curve were examined in these experiments. The results from a two-year study showed that nitrogen fertilization has significant effects on promoting the net photosynthetic rate (Pn) in leaves at grain-filling stage and the single palnt grain yield at harvesting stage (P<0.05) of Q319, whereas there is no substantial effect on HZ4. JIP-test analysis showed that nitrogen fertilization significantly increased the electron donor and acceptor performances in the reaction center of photosystem II (PS II) (P<0.05). The increased performance of the electron transport chain after the electron acceptor in the PSII reaction center was greater in Q319 than that in HZ4, therefore it reduced the excessive excitation energy production by PSII and significantly improved the coordination between PSII and PSI. Although the performance of the electron transport chain after the electron acceptor in the PSII reaction center was increased in HZ4, the increase was not big enough to improve the coordination between PSII and PSI, therefore the yield of Pn and the single plant is still significantly lower than that of Q319.