高寒区玉米叶片光合参数日变化及其与环境因子关系

Relationship Between Diurnal Changes of Net Photosynthetic Rate and Environmental Factors in Leaves of Maize in Alpine Cold Region

为探明高寒区玉米叶片光合相关参数日变化特性,以“隆平702”玉米品种为材料,在安图县松江镇南道村进行田间试验,利用Li-6400光合仪在抽雄吐丝期测定叶片净光合速率(P_(n))、气孔导度(G_(s))、蒸腾速率(Tr)、胞间CO_(2)浓度(C_(i))以及当天的光合有效辐射(PAR)、空气温度(T)和空气相对湿度(RH),分析叶片光合相关参数日变化及其与环境因子的关系。结果表明:高寒区玉米叶片P_(n)与Tr的日变化均为双峰曲线变化,P_(n)的峰值分别出现在10:00和14:00;Tr的峰值分别出现在10:00和13:00;G_(s)的最大值出现在10:00,随后呈下降趋势;C_(i)呈先下降后上升的趋势;06:00—10:00,P_(n)与PAR,T,RH分别呈极显著正相关、显著正相关、极显著负相关(r=0.927,r=0.574,r=-0.765);14:00—18:00,P_(n)与PAR,T,RH的相关性分别为r=0.921,r=0.553,r=-0.712;06:00—10:00时,G_(s)与PAR极显著正相关(r=0.772),与RH呈显著负相关(r=-0.550);10:00—14:00,G_(s)与PAR呈显著正相关(r=0.545),与RH呈正相关(r=0.482);06:00—10:00,Tr与PAR呈极显著正相关(r=0.953),与RH均呈极显著负相关(r=-0.857);06:00—10:00,C_(i)与PAR呈极显著负相关(r=-0.655)。可见,空气温度和光合有效辐射偏低、空气相对湿度偏高是限制该高寒区域玉米光合物质生产的主要因子。

The characteristics of photosynthetic parameters of maize leaves in alpine region were investigated.Field experiments were carried out in Nandao village,Songjiang town,Antu county,using Longping 702 maize varieties as materials,net photosynthetic rate(P_n),stomatal conductance(G_s),transpiration rate(T_r),intercellular CO_(2) concentration(C_i),photosynthetically active radiation(PAR),air temperature(T),and air relative humidity(RH)of maize leaves were determined using a Li-6400photosynthetic apparatus during the extraction and male-spraying period.The relationship between photosynthetic parameters and environmental factors was analyzed.The results showed that:the changes of leaf P_(n) and Tr of maize in alpine region were double peak curve,the peak of P_(n) appeared at 10:00 and 14:00,respectively.T_r peaks were around 10:00 and 13:00,respectively.G_s maximum reached at 10:00,followed by a downward trend.Ci decreased first and then increased.At 6:00—10:00,P_(n) showed an extremely significantly positive correlation,a significantly positive correlation,and an extremely significantly negative correlation with PAR,T,and RH,respectively(r=0.927,r=0.574,r=-0.765);At 14:00—18:00,the correlation between P_n and PAR,T,and RH was r=0.921,r=0.553,r=-0.712,respectively;At 06:00—10:00,G_s showed an extremely significantly positive correlation with PAR(r=0.772)and a significantlt negative correlation with RH(r=-0.550);At 10:00—14:00,G_s showed a significantly positive correlation with PAR(r=0.545)and a positive correlation with RH(r=0.482);At 06:00—10:00,T_r showed an extremely significantly positive correlation with PAR(r=0.953),and an extremely significantly negative correlation with RH(r=-0.857).At 06:00—10:00,C_i showed an extremely significantly negative correlation with PAR(r=-0.655).The results showed that low air temperature and photosynthetically active radiation and high air relative humidity are the main factors limiting the production of photosynthetic materials in maize.