沿海沙地5种相思树叶绿素荧光参数夏季日变化

Diurnal changes of chlorophyll fluorescence parameters in 5 Acacia species on coastal sand in summer

以直杆大叶、厚荚、卷荚、肯氏和纹荚5个品种相思树为材料,研究叶绿素荧光参数在夏季的日变化规律.结果表明,5种相思树在12:00-16:00表现出不同程度的光抑制,光系统Ⅱ(PSⅡ)最大光能转换效率(F v/F m)和PSⅡ潜在活性(F v/F0)分别为0.730-0.854和2.711-5.592.在温度最高的14:00,5种相思树F v/F m和F v/F0的大小均为:直杆大叶>肯氏>厚荚>纹荚>卷荚,16:00的大小均为:肯氏>直杆大叶>厚荚>纹荚>卷荚.卷荚的最小初始荧光(F0)明显大于其他树种,而F v/F m和F v/F0均显著小于其他树种,表明其开放的PSⅡ反应中心的光量捕捉效率低于其他树种.

Diurnal changes of chlorophyll fluorescence parameters in 5 different Acacia plantations in summer were studied. Rosults showed that degrees of fight inhibition in different Acacia species were different from 12：00 to 16：00. The maximum energy conver- sion efficiency of photosystemⅡ（PSⅡ） （Fv/Fm） and potential activity （Fv/Fo） were 0.730 -0.854 and 2.711 -5.592 respec- tively. The change of Fv/Fm and Fv/Fo of different Acacia species showed the similar trend, that was at 14：00, A. auriculi 〉 A. cun- ninghami 〉 A. crassicarpa 〉 A. auiacacarpa 〉 A. cincinnata i while at 16 ： 00, A. cunninghami 〉 A. auriculi〉 A. crassicarpa 〉 A. aulo- cocarpa 〉 A. cincinnata. The minimal fluorescence （ Fo ） of A. cincinnata was obviously higher than that of other Acacia species, but Fv/Fm and Fv/Fo were significantly lower than those of the other four Acacia species, and its energy capture e/Hciency of opening PS 11 reaction center was lower than that in other Acacia species.