高油115籽粒灌浆期光能利用效率

在种植密度为3万株 hm^-2的大田条件下，研究了高油115上、中和下部叶片灌浆期光能利用和耗散特性。结果表明，高油115净光合速率（P_n）、蒸腾速率（T_r）、气孔导度（G_s）、叶色值等均显著低于普通玉米农大108（P<0.05），细胞间隙CO₂浓度（C_i）和水分利用效率（WUE）略低于普通玉米（P>0.05）；PSⅡ最大光能转化效率（F_v/F_m）显著低于农大108；PSⅡ活性（F_v/F_o）略低于普通玉米（P>0.05）。高油115表观电子传递速率低于农大108，在相同光能下，高油玉米热耗散比例较普通玉米高，光能利用效率明显低于普通玉米叶片，3个叶位中中部叶差异最大，表明高油115光合速率较低主要是因光能利用率偏低造成的。在高油玉米育种和栽培中应选用高光效自交系配组和改善肥水条件以提高光能利用率。

Light Energy Utilization Efficiency of High Oil Corn 115 at Grain Filling Stage

High oil corn is a value-added corn type，which contains more oil and higher quality protein than normal corn. At present high oil corn has not been widely planted by farmers because its grain yield is lower than that of normal corn. The yield of high oil corn is restricted by lower net photosynthetic rate. A field experiment with a planting density of 30 000 plants ha^-1 was carried out to reveal the reason of lower net photosynthetic rate of high oil corn. The technique of chlorophyll fluorescence was used to measure light energy utilization efficiency of high oil corn. Light energy utilization and dissipation of upper, middle and basal leaves of high oil corn 115 in grain filling stage was studied. Compared with ND108，net photosynthetic rate (P_n), transpiration rate (T_r), stomal conductance (G_s) of were significantly lower（P<0.05）; intercellular CO₂ concentration (C_i) and water use efficiency of HOC115 (WUE) were slightly lower in ND108 (P>0.05). PSⅡ maximal photochemical efficiency (F_v/F_m) of HOC115 was lower significantly than that of ND108. PSⅡ activity (F_v/F_o) of HOC115 was slightly lower than that of ND108 (P>0.05). Apparent relative electron transportation rates of HOC115 were lower than that of ND108. Compared with ND108, the proportion of light energy used in heat dissipation by HOC115 was higher when light energy was constant. This result indicated that light energy utilization efficiency of HOC115 is lower than that of ND108. The largest light utilization efficiency difference between HOC115 and ND108 was observed in middle leaves. In conclusion, photosynthetic rate of HOC115 is lower mostly due to lower light energy utilization efficiency. In high oil corn breeding and cultivation, we should select high photosynthetic inbred lines and improve the growing conditions with suitable fertilizer and irrigation to enhance their light use efficiency.