华北水利水电大学学报(自然科学版)

为探明拔节期和灌浆期旱涝急转对夏玉米光合特性与产量的影响，采用测坑试验，分别在夏玉米拔节期和灌浆期设置旱转轻涝(LF)和旱转重涝(SF)2个旱涝急转处理，以适宜水分处理(CK)为对照，测定叶片叶绿素相对含量(SPAD)、净光合速率(P_n)、蒸腾速率(T_r)、气孔导度(G_s)、胞间CO₂浓度(C_i)以及最终产量。结果表明：旱胁迫处理期间，各处理叶片的SPAD、P_n、T_r和G_s随胁迫时间的延长逐渐降低；旱涝急转处理过程中，P_n、T_r和G_s随着涝胁迫持续时间的延长呈先上升后下降的趋势；旱涝急转结束时，P_n、T_r和G_s均小于CK;旱涝急转结束后，P_n、T_r和G_s呈现逐渐恢复的过程，LF的恢复速度快于SF,C_i与P_n、T_r和G_s呈相反的变化趋势。拔节期旱涝急转LF和SF产量与CK相比显著降低13.60%和18.88%,灌浆期降低5.24%和10.86%;SF处理对减产的影响更显著。夏玉米在拔节期发生旱涝急转对光合特性以及产量的影响较大，生产上尽量避免该阶段发生旱涝急转。

To investigate the impacts of drought-waterlogging abrupt alternation(DWAA) during the jointing and filling stages on photosynthetic characteristics and yield of summer maize, a pit experiment was conducted. Two DWAA treatments—drought followed by light waterlogging(LF) and drought followed by severe waterlogging(SF)—were applied during these critical stages, with a well-watered treatment(CK) as the control. Key parameters including leaf chlorophyll relative content(SPAD), net photosynthetic rate(P_n), transpiration rate(T_r), stomatal conductance(G_s), intercellular CO₂ concentration(C_i), and final yield were measured. Results showed that during drought stress, SPAD, P_n, T_r, and G_s gradually decreased across all treatments as stress duration increased. In the DWAA process, P_n, T_r, and G_s initially increased and then decreased with prolonged waterlogging stress. At the end of DWAA, these parameters were consistently lower than those of CK. Post-DWAA, P_n, T_r, and G_s exhibited gradual recovery, with LF demonstrating faster recovery than SF. C_i displayed an inverse trend compared to P_n, T_r, and G_s. Compared to CK, yields under LF and SF treatments during the jointing stage significantly decreased by 13.60% and 18.88%, respectively, while reductions during the filling stage were 5.24% and 10.86%. SF exerted a more pronounced impact on yield loss. The study indicates that DWAA during the jointing stage critically impairs photosynthetic performance and yield formation in summer maize, suggesting the necessity to avoid such stress events during this phase in agricultural practice.