运用两种光谱仪（SPAD-502叶绿素仪与Sunscan植物冠层分析仪）分析了华北平原不同耐热型春玉米品种的光合性能对灌浆期高温的光谱学特征响应。 田间试验于2011年—2012年在河北省吴桥县进行。 品种选用天玉198、 兴玉998与天润606, 设置2个播种期（4月15日与4月25日）, 于灌浆期测定3个光谱特征值, 即叶绿素相对含量（SPAD）、 叶面积指数（leaf area index, LAI）与光合有效辐射（photosynthetically active radiation, PAR）。 结果表明, 播种期4月15日与4月25日相比, 春玉米灌浆期≥33 ℃日最高气温的天数与日均温分别增加了3.5 d和0.8 ℃, 而日照时数、 降雨量、 气温日较差及生育期长短均相似; 天玉198与兴玉998、 天润606相比, 耐热指数（stress tolerance indices, STI）分别高2.9%, 11.0%; 根据STI由大到小的顺序, 将天玉198、 兴玉998与天润606分别定为耐热型、 较耐热型与不耐热型品种; 播种期4月15日, 天玉198比兴玉998、 天润606的产量分别高4.1%, 13.7%, SPAD分别高12.5%, 19.6%, LAI分别高5.3%, 5.6%, PAR分别高4.0%, 14.0%; 播种期4月25日, 产量分别高1.3%, 2.8%; SPAD分别高3.5%, 6.0%, LAI分别高1.7%, 4.1%, PAR分别高-4.4%, 0.9%; 三个品种在高温胁迫环境下产量差异显著, 耐热型品种具有显著的产量、 SPAD与LAI优势（p＜0.05）。 播种期4月15日相对于4月25日, 天玉198、 兴玉998、 天润606的产量分别降低了3.2%, 5.9%, 12.6%; SPAD分别降低了8.6%, 12.4%, 15.7%; LAI分别降低了11.7%, 17.6%, 19.8%; PAR分别降低了3.4%, 11.3%, 14.5%; STI与SPAD的降幅（r=-0.883, p＜0.05）、 LAI的降幅（r=-0.853, p＜0.05）均呈显著负相关, 与PAR的降幅（r=-0.923, p＜0.01）呈极显著负相关; SPAD的降幅与PAR的降幅（r=0.872, p＜0.05）呈显著正相关; LAI的降幅与PAR的降幅（r=0.943, p＜0.05）呈极显著正相关。 综上所述, 耐热型春玉米品种在灌浆期受高温胁迫时, 能够在个体层面保持相对较高的叶绿素含量, 在群体层面保持相对较高的叶面积, 进而保持了较高的光能截获与利用, 削弱了高温对光合的抑制程度, 缩小了产量降幅, 实现了高产与稳产; 品种的耐热性可以通过其光谱特征（SPAD, LAI和PAR）对高温的响应作为鉴定与评价的主要指标之一, 为利用光谱特征研究玉米耐热性提供了依据。

This paper discussed the response of spectral characteristics on high temperature at grain filling stage of different spring maize varieties by adopting two spectrometer (SPAD-502 Chlorophyll Meter and Sunscan Plant Canopy Analyzer), and analyzed the impact of high temperature on the photosynthetic properties of spring maize in North China Plain. The test was conductedfrom the year 2011 to 2012 in Wuqiao County, Hebei Province. This test chose three different varieties, i.e. Tianyu 198 (TY198), Xingyu 998 (XY998) and Tianrun 606 (TR606), then two sowing date (April 15th and April 25th) was set. We analyzed chlorophyll relative content (SPAD), leaf area index (LAI) and photosynthetically active radiation (PAR) at grain filling stage. The results showed that the days of daily maximum temperature above 33 ℃ and the mean day temperature at grain filling stage in spring maize sowing on April 15th increased 3.5 d and 0.8 ℃, respectively, compared to that sowing on April 25th, moreover the sunshine hours, rainfall, diurnal temperature and length of growing period were similar. Compared with XY998 and TR606, TY198’s stress tolerance indices (STI) increased by 2.9% and 11.0%, respectively. According to STI from high to low order, TY198, XY998 and TR606 respectively as heat resistant type, moderate heat resistant type and thermolabile type variety. TY198, compared with XY998 and TR606 sowing on April 15th, yield increased by 4.1% and 13.7%, SPAD increased by 12.5% and 19.6%, LAI increased by 5.3% and 5.6%, PAR increased by 4.0% and 14.0%. Sowing on April 15th, yield increased by 1.3% and 2.8%, SPAD increased by 3.5% and 6.0%, LAI increased by 1.7% and 4.1%, PAR increased by -4.4% and 0.9%. Three varieties had significant yield differences in the environment of high temperature stress, heat resistant type have significant (p<0.05) advantage in the aspect of yield, SPAD and LAI. The production of TY198, XY998 and TR606 sowing on April 15th compared to that sowing on April 25th decreased by 3.2%, 5.9% and 12.6%, and SPAD decreased by 8.6 %, 12.4% and 15.7%, LAI decreased by 11.7%, 17.6% and 19.8%, PAR decreased by 3.4%, 11.3% and 14.5%; STI had a significant negatively correlated with SPAD fall range (r=-0.883, p<0.05) and LAI fall range (r=-0.853, p<0.05), and highly significantly negatively correlated with PAR fall range (r=-0.923, p<0.01); while SPAD fall range and PAR fall range showed a significant positive correlation (r=0.872, p<0.05); LAI fall range and PAR fall range were significantly positive correlation (r=0.943, p<0.05). In conclusion, heat tolerant type varieties of spring maize under high temperature stress at gain filling stage could maintain a relatively high content of chlorophyll at the individual level, a relatively high leaf area at the group level, and then keep a higher luminous energy interception and utilization, and weakened inhibition magnitude of high temperature on photosynthetic capacity, reduced the yield fall range, then achieved high and stable yield. The heat tolerance in varieties could be one of the main indicators for identification and evaluation the response to high temperature by spectral characteristics (SPAD, LAI and PAR). Thus it provides a basis by using spectral characteristics to study heat tolerance on maize.