【作者】 张国斌； 郁继华； 颉建明； 冯致；

【机构】 甘肃农业大学农学院；

【摘要】 以辣椒（Capsicum annuum L）幼苗为材料,研究了低温弱光胁迫对辣椒幼苗叶片中气体交换参数、叶绿素荧光淬灭特性和光能分配的影响。结果表明:低温弱光导致辣椒幼苗叶片中净光合速率（P_n）不同程度的下降,细胞间隙CO₂浓度（C_i）浓度上升,而气孔限制值（L_s）则下降,引起P_n下降的原因主要是非气孔因素;低温弱光胁迫后辣椒幼苗叶片的PSⅡ最大光化学效率（F_v/F_m）、PSⅡ光合电子传递量子效率(φ_PSⅡ)、光化学淬灭系数（q_p）和天线转化效率（F_v′/F_m′）均不同程度地降低,但偏低温（19℃/12℃）90μmol·m^-2·s^-1弱光处理下几乎不下降;同时,吸收光强分配于光化学反应的部分(P_rate)减少,而天线热耗散(D_rate)和反应中心的能量耗散（E_x）比例上升,但天线热耗散为主要的过剩光能分配途径。从整体看,临界低温弱光使上述参数变化的程度要比偏低温弱光明显,而弱光的作用在不同的低温区影响不同。更多还原

【Abstract】 Effects of low temperature and poor light on Chlorophyll content,gas exchange,chlorophyll fluorescence quenching and absorbed light allocation in leaves of pepper （Capsicum annuum L.） seedlings were studied.The results showed that net photosynthetic rate and stomatal limitation value decreased,however intercellular CO₂ concentration decreased.The cause of reduction of net photosynthetic rate in pepper seedlings under low temperature and poor light stress might be mainly non-stomata limitation.F_v/F_m,（?）_PS（?）,q^P and F_v′/F_m′,decreased with degree increasing and time prolonging of low temperature and poor light.At the same time,P_rate decreased,but D_rate and E_? increased under low temperature and poor light.D_rate was the main way of superfluous light allocation.In all,the change of the above parameters were smaller under lower temperature （19℃/12℃） than critical temperature （15℃/80℃）,but poor light had different influence on different low temperature plot.更多还原