Abstract: Significant differences of photosynthetic rate (Pn) in the leaves of two maize (Zea mays) strains (‘Shuang 105’ and ‘40×44’) growing in the field were observed. Compared with the strain of ‘Shuang 105’, the strain of ‘40×40’ had higher Pn, higher photo-chemical efficiency of PS Ⅱ (Fv/Fm and △F/Fm') at different development stages. Meanwhile, it had better plant height and leaf area, but it's content of chlorophyll was lower. According to the results of the experiment, ‘Shuang 105’ had higher concentration of intercellular CO₂ (Ci) though it had lower stomatal conductance (Gs) and Pn. Hence, the differences in Pn between the two strains did not result from the difference in Gs, but probably from that in light reaction system.

Key words: photosynthetic rate, stomatal conductance, photochemical efficiency, maize

摘要： 田间生长的两个玉米品系"双105"和"40×44"叶片净光合速率(Pn)存在显著差异。在不同的生长阶段,"40×44"Pn值均比"双105"高10%~32%,而且PSII光化学效率(Fv/Fm和△F/Fm')也较高,表现为植株较高,叶片较大,但叶绿素含量较低。尽管"双105"品系具有较低的光合速率和较低的气孔导度(Gs),但其胞间CO₂浓度(Ci)却略高于"40×44"。因此,这两个玉米品系叶片光合速率的差异并非气孔因素,而可能源于光合机构的光反应系统。

关键词: 光合速率, 气孔导度, 光化学效率, 玉米