光照强度和氮素水平对玉米生长发育、光合生理及干物质积累的影响

Effects of Light Intensity and Nitrogen Level on the Growth,Photosynthetic Physiology and Dry Matter Accumulation of Maize

【目的】探明光氮互作条件下玉米生长发育特征及光合生理机制,为通过合理施肥缓解玉米弱光胁迫提供科学依据。【方法】采用盆栽试验,研究不同光照强度和氮素水平对玉米生长发育、光合生理及干物质积累的影响。【结果】中低氮水平下,遮阴处理的玉米生育后期株高较自然光处理有所降低;不同施氮水平灌浆期上部叶、穗位叶和下部叶叶面积也均小于自然光处理,下降幅度分别为13.0%~35.9%、6.1%~28.5%和9.7%~26.4%,生育前期功能叶片叶绿素含量和全生育期净光合速率也有不同程度降低,拔节期叶中可溶性糖含量显著下降11.1%~46.5%(P<0.05);中高氮水平下,遮阴处理玉米总生物量显著降低33.1%~49.7%(P<0.05)。遮阴条件下,低氮处理的不同部位叶片叶面积、净光合速率及根长均高于高氮处理,叶中可溶性糖含量及总生物量也分别较中高氮处理增加19.4%~108.3%和51.1%~85.6%。【结论】遮阴条件下,玉米生长发育受抑制且低氮处理较中高氮处理更有助于玉米干物质累积。

[Purpose]As for light and nitrogen,the characteristics of growth and photosynthetic physiology of maize(Zea may L.)were studied,in order to provide scientific basis for alleviating lowlight stress through rational fertilization.[Methods]Pot experiments were conducted to study the effects of different light intensities and nitrogen levels on the growth,photosynthetic physiology and dry matter accumulation of maize.[Result]Plant height of maize under shading treatment was lower than those of natural light treatment in low and middle nitrogen levels.The areas of upper leaf,ear leaf and lower leaf at the filling stage in different nitrogen levels were decreased by 13.0%-35.9%,6.1%-28.5%and 9.7%-26.4%,respectively,compared with the natural light treatment;the chlorophyll contents of the functional leaves at the early growth stage and net photosynthetic rate at the whole growth stage were decreased to different degrees.Soluble sugar contents in leaves at the jointing stage were decreased significantly by 11.1%-46.5%,and total biomass under shading treatment was decreased by 33.1%-49.7%in middle and high nitrogen levels.The leaf areas of different parts,net photosynthetic rate and root length of low nitrogen treatment were higher than those of high nitrogen treatment,and soluble sugar content in leaves and total biomass under shading treatment were also increased by 19.4%-108.3%and 51.1%-85.6%respectively,compared with medium and high nitrogen treatments.[Conclusion]Under shading condition,the growth and development of maize were restrained,and low nitrogen treatment was beneficial to dry matter accumulation compared with middle and high nitrogen treatments.