以吉单261和京单28两个玉米品种为试验材料,研究水分胁迫对玉米叶片光合特性及叶绿素荧光参数的影响.结果表明:水分胁迫下玉米叶片的最大净光合速率、光补偿点、光饱和点和表观量子效率均显著下降;基础荧光显著增加,最大荧光、可变荧光和PSⅡ光化学效率显著降低;随着光强增加,水分胁迫条件下的光化学猝灭系数和实际光化学效率下降幅度明显加剧;非光化学猝灭系数和表观电子传递速率增加幅度则明显减缓.表明水分胁迫使玉米叶片光合性能减弱,PsⅡ反应中心开放部分的比例减少,光合电子传递能力下降,PSⅡ潜在活性受到抑制,过多的光能多是以非光化学猝灭等其他形式耗散掉,从而保护光合机构免受伤害.

Use maize Jidan 261 and Jingdan 28 as materials. Research the effects of water stress on chlorophyll fluO₂ rescence parameters of maize leaf. The result sho wed that the light2saturated net photosynthetic rate, light compensation point and light saturation point and values of intrinsic quantumefficiency for CO₂uptake were decreased on water stress. The basis fluorescence of the maize leaveswas significantly increased. The max fluorescence, the variable fluorescence and photochemical efficiency were significantly decreased. With the increased of light, The photochemical quenching coeffi2 cient and actual photochemical efficiency were significantly decreased. But the non2photochemical quenching coefficient and apparent electron transport rate were increased slowly. Result showed that the photosynthesis competence ofmaize leaf was lo wer under stress.The inverse proportion of PS ò was unfolded slowly.The capability of electron transport of photO₂ synthesis was decreased, and PS ò latency active was restrained. The superabundance light was dissipation by other aP₂ proach such as non2photochemical quenching mode.To protected photosynthetic structures from injure.