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小麦叶片在晴天的表观量子效率(AQY)和光系统Ⅱ光化学效率(Fv/Fm)有明显的日变化,中午前后降低,表明小麦叶片在田间条件下发生了光抑制。AQY和Fv/Fm在下午光照减弱后很快恢复的事实说明,光抑制发生的主要机理可能是非辐射能量耗散的增加。中午前后光呼吸速率(P_r)的增加,既削弱了净光合,也降低了光合效率。在强光下连续抑制光呼吸3小时,会明显地降低净光合速率,加重光合作用的光抑制。这些结果说明,光呼吸在强光和高温条件下的增强。对于消耗光合午休时的过剩能量,防止发生更严重的光抑制,免除光合机构发生不可逆的破坏,具有重要的作用。
The apparent quantum yield (AQY) and photosystem Ⅱ photochemical efficiency (Fv / Fm) of wheat leaves in the sunny days had obvious diurnal changes, and decreased around noon, suggesting that the photosynthesis of wheat leaves under field conditions was photoinhibited. The fact that AQY and Fv / Fm resume soon after the afternoon light weakens suggests that the main mechanism of photoinhibition may be the increase of non-radiative energy dissipation. The increase of photorespiration (P_r) around noon not only weakened the net photosynthesis, but also reduced the photosynthetic efficiency. Continued inhibition of photorespiration for 3 hours in bright light significantly reduced net photosynthetic rate and aggravated photosynthesis inhibition. These results show that photorespiration is enhanced under high light and high temperatures. For the consumption of photosynthesis lunch when the excess energy to prevent the occurrence of more serious photoinhibition, photosynthetic institutions to avoid irreversible damage, has an important role.