低温胁迫对茄子幼苗叶片气体交换、PSⅡ光化学效率和光能分配的影响

Effects of low temperature stress on gas exchange,photochemical efficiency of PSⅡ and light energy allocation in eggplant seedling leaves

研究了低温胁迫对茄子幼苗叶片气体交换、PSⅡ光化学效率及光能分配的影响。结果表明,低温胁迫10 d后,净光合速率(Pn)、气孔导度(Gs)和气孔限制值(Ls)显著下降;PSⅡ潜在活性(Fv/Fo)、PSⅡ最大光化学效率(Fv/Fm)、天线转化效率(Fv’/Fm’)、实际光化学效率(ΦPSⅡ)、光化学猝灭系数(qP)均低于对照,胞间CO2浓度(Ci)、非光化学猝灭(NPQ)和PSⅡ激发能压力(1-qP)均高于对照,激发能在两个光系统间的分配不平衡性(β/α-1)增大。当光照增强时,低温胁迫下茄子幼苗叶片吸收的光能中应用于光化学反应的份额(P)显著降低,天线热耗散的份额(D)显著增加。天线热耗散是耗散过剩能量的主要途径。

Effects of low temperature stress on gas exchange, photochemical efficiency, and absorbed light energy allocation were studied in eggplant seedling leaves. The results indicated that after low temperature stress for 10 days, the photosynthetic rate （Pn）, stomatal conductance （Gs） and stomatal limit value （Ls ） were significantly decreased, meanwhile, potential photochemical efficiency （Fv/Fo）, maximum photochemical efficiency of PS Ⅱ （Fv/Fm）, efficiency of excitation captured by open PSII centers （ Fv＇ / Frn＇ ）, actual PS Ⅱ efficiency （ ФPS Ⅱ ） and photochemical quenching index （qP） were also decreased. However, intercellular CO2 concentration （ Ci ）, non-photochemical quenching （NPQ） and high excitation pressure （1-qP） were increased, and the deviation from full balance between PSⅠ and PSⅡ （β/α- 1 ） was improved, compared with the control. The proportion of the photochemical reaction of PS Ⅱ （P） allocated by absorbed light energy was reduced and the proportion of antenna heat dissipation （D） was increased. Antenna heat dissipation was the main way for excessive energy dissipation.