摘要
为了探讨夜间低温对滇南地区主要栽培的小粒种咖啡(Coffeaarabica)和大粒种咖啡(Coffea liberica)光合作用的影响,于西双版纳雾凉季对盆栽幼苗进行了连续3d的4℃夜间低温处理,并于原地恢复3d,测定了叶片的一些生理生态指标。结果表明,经4℃夜间低温处理3d后,虽然两种咖啡非辐射耗散能力增强,胡萝卜素/叶绿素(Car/Chl)升高,但净光合速率(Pn)、气孔导度(Gs)和黎明原初光化学效率(Fv/Fm)降低,初始荧光(Fo)升高,以及过氧化氢(H2O2)和丙二醛(MDA)的积累,表明夜间低温对两种咖啡光合机构均产生了明显的破坏,导致净光合速率下降的气孔因素和非气孔因素同时存在。虽然正常条件下两种咖啡净光合速率没有显著差异,但与大粒种咖啡相比,低温处理后,小粒种咖啡的Pn,Fv/Fm下降的比例小,MDA积累的量少,且在3d的恢复后基本可以恢复到原初值,表明小粒种咖啡相对比较耐寒,这与其较强的非辐射耗散能力,较大的Car/Chl及较强的恢复能力有关。
To explore the effects of nocturnal low temperature on photosynthesis of Coffea liberica and Coffea arabica,the two dominant coffee species in Southern Yunnan,the potted seedlings were exposed to nocturnal low temperature (4℃) for 3 days and then recovered for another 3 days under ambient environment during the cool and foggy season of Xishuangbanna in 2003.The photosynthesis parameters and the content of H 2O 2 and MDA were measured in mature leaves of the two species.The results showed that after three day's nocturnal low temperature exposure,although thermal dissipation capacity (NPQ) and Car/Chl ratio increased,the net photosynthetic rate (Pn),stomatal conductance (Gs) and initial photochemical efficiency of photosystem II (Fv/Fm) at dawn decreased greatly in leaves of the two species,accompanied with the accumulation of H 2O 2 and MDA,which suggested that their photosynthetic apparatuses were destroyed,and both stomatal and non-stomatal limitation contributed to the decrease of net photosynthetic rate.There were no significant differences of photosynthetic ability between the two coffee species in normal conditions.But compared to C.liberica,C.arabica had less decrease of Pn and Fv/Fm,less accumulation of MDA after nocturnal low temperature exposure,and recovered more quickly than C.liberica.That means that C.arabica is more chilling-tolerant than C.liberica.The mechanism is related with its higher Car/Chl ratio,heat dissipation capacity and higher ability to recover.
出处
《生态学杂志》
CAS
CSCD
北大核心
2005年第5期478-482,共5页
Chinese Journal of Ecology
基金
中国科学院和云南省合作资助项目(WK20007)。
关键词
夜间低温
光合速率
丙二醛
小粒种咖啡
大粒种咖啡
nocturnal low temperature,photosynthetic characteristics,MDA,Coffea arabica,Coffea liberica.
