光、氮及其互作对玉米光合特性与物质生产的影响

以豫玉22为试验材料,采用盆栽试验,设置2种遮光处理和3个氮肥水平,研究光、氮及其互作对玉米光合特性和物质生产的影响。结果表明,相对于不遮光处理,抽雄前3 d开始遮光、吐丝后10 d恢复自然光照处理玉米叶片光合速率和叶绿素a含量下降,叶绿素b和总叶绿素含量升高,胞间CO2浓度上升;成熟期不施肥、施肥120、240 kg/hm2的干物质积累量分别降低33.66%、31.69%、24.84%,产量分别降低52.50%、49.10%、40.92%。抽雄前3 d开始遮光、吐丝后10 d恢复自然光照处理,随施氮量的增加,叶片中叶绿素a、叶绿素b、总叶绿素含量以及光合速率均显著上升,成熟期施肥240 kg/hm2处理干物质积累量分别比不施肥、施肥120 kg/hm2增加42.45%、17.39%,产量分别增加59.93%、22.24%。弱光胁迫条件下增施氮肥可以改善玉米的光合特性,增加玉米干物质积累量,减少玉米产量损失。

Effects of Light, Nitrogen and Their Interaction on Photosynthetic Traits and Matter Accumulation of Maize

A pot experiment was conducted using maize cultivar YY22 with three nitrogen levels(N1:0 kg/ha, N2:120 kg/ha, N3:240 kg/ha) and two light treatments(L1:no shading, L2:shading after 3 days before tasselling, and restored natural light treatment after silking) to study the effects of light, nitrogen and their interaction on photosynthetic traits, matter accumulation and yield of maize. The results showed that, compared with L1 treatment, L2 not only reduced the leaf photosynthetic rate, chlorophyll a, chlorophyll b, and total chlorophyll content, but also decreased dry matter accumulation and yield. With the increasing of nitrogen application, the leaf photosynthetic rate, chlorophyll a, chlorophyll b and total chlorophyll content were significantly increased, while dry matter accumulation at maturity and yield of N3 increased respectively over than N1 and N2 by 42.45%, 17.39% and 59.93%, 22.24% under L2. So, nitrogen can partially alleviate the effect of damage by weak light stress and improve photosynthetic traits, increase dry matter accumulation and yield.