Physiological basis of the difference in net photosynthetic rate of leaves between two maize strains

摘要

Significant differences in net photosynthetic rate (P_N) of leaves between two. maize (Zea mays L.) strains (Shuang 105 and 40 X 44) grown ill tile field were observed. At several growth stages, P_N of 40 X 44 was higher than that of Shuang 105 (from 10.3 to 32.5 ). Moreover, the strain 40 X 44 had a higher plant height, larger leaf area, lower chlorophyll content, and higher photochemical efficiency of photosystem 2 (PS2) (F_v/F_m and #DELTA#F/F_m') than strain Shuang 105. Shuang 105, which showed lower P_N, had lower stomatal conductances (g_s) but slightly higher intercellular CO_2 concentrations (C_i) than those of 40~44. Hence the differences in P_N between the two strains did not result from the difference in g_s, but probably from that in light reaction system.