风箱果和紫叶风箱果叶片光系统Ⅱ功能对秋季低温的响应

Response of Photosynthetic Function of photosystem Ⅱ in Leaves of Physocarpus amurensis Maxim and P. opulifolius in Autumn Low Temperature Stress in Cold Regions

以风箱果(Physocarpus amurensis Maxim)和紫叶风箱果(Physocarpus opulifolius"Diabolo")为材料,利用快速叶绿素荧光动力学技术研究了两种植物叶片光系统Ⅱ(PSⅡ)特点对北方秋季自然低温胁迫的响应。结果表明:在正常温度时,风箱果和紫叶风箱果叶片的叶绿素荧光参数均无显著差异;在秋季低温胁迫时,风箱果叶片的快速叶绿素荧光诱导动力学(OJIP)曲线变化幅度明显大于紫叶风箱果,其PSⅡ反应中心光化学活性对低温胁迫更为敏感,风箱果叶片J点和K点相对可变荧光强度(VJ和VK)增加幅度明显大于紫叶风箱果,风箱果叶片PSⅡ供体侧放氧复合体(OEC)活性和受体侧电子由初级电子受体(QA)向次级电子受体(QB)的传递过程更易受到低温的抑制。紫叶风箱果叶片超氧阴离子(O-2)产生速率和H2O2质量摩尔浓度,在秋季低温胁迫时的增加幅度明显小于风箱果,L点的相对可变荧光强度(VL)增加幅度也明显小于风箱果,活性氧导致风箱果叶片类囊体膜的损伤程度大于紫叶风箱果。在秋季低温胁迫时,紫叶风箱果光合机构的伤害程度明显低于风箱果;在高寒区秋季,紫叶风箱果比风箱果更具有抗寒性。

The responses of photosystem Ⅱ（ PS Ⅱ） function in leaves of native Physocarpus amurensis Maxim and the introduced P. opulifolius ＂Diabolo＂to natural low temperature in autumn of Northern China were investigated using the fast chlorophyll fluorescence induction dynamics. The chlorophyll fluorescence parameters in leaves of P. amurensis and P. opulifolius under normal temperature were no significant differences. However,under the low temperature in autumn,the O-JI-P fluorescence induction dynamics curve（ OJIP） in leaves of P. amurensis was changed greater than that in P. opulifolius,and the PSⅡ reaction center photochemical activity was more sensitive to low temperature because the relative variable fluorescence（ VJand VK） at the J and K points in leaves P. amurensis was significantly greater than that in P. opulifolius,and the activities of oxygen-evoling complex（ OEC） on the PSⅡ donor side and electron transfer process from electron receptor quinine A（ QA） to B（QB） on receptor side were more susceptible to low temperature. Superoxide anion（O-2） production rate and H2 O2 content in the leaves of P. opulifolius under low temperature stress in autumn were significantly lower than that in P. amurensis,and relative variable fluorescence（ VL） at point L was significantly smaller than that in P. amurensis. This result showed that reactive oxygen species caused irreparable damage to the thylakoid membrane in leaves of P.amurensis more than that in P. opulifolius. Therefore,the damage degree of PSⅡ in leaves of P. opulifolius under low temperature was significantly lower than that in P. amurensis,and P. opulifolius is suitable for areas at rather low temperature.