越冬期不同产地绿竹叶绿素荧光参数的动态变化

测定了4个产地绿竹在越冬期叶绿素荧光参数的动态变化,分析了不同产地绿竹抵御低温的适应机制。结果表明:绿竹对低温反应敏感,在越冬期内,其叶绿素初始荧光(F0)、非光化学猝灭系数(qN)有所升高,而最大荧光(Fm)、可变荧光(Fv)、PSⅡ最大光能转换效率(Fv/Fm)、PSⅡ潜在活性(Fv/F0)、光化学猝灭系数(qP)、PSⅡ实际光量子效率(ΦPSⅡ)等指标呈现出与月平均气温相一致的动态变化,即先下降后上升。低温胁迫后绿竹叶片通过光合作用调节而形成自我保护机制,随着低温胁迫的增强,PSⅡ潜在活性和原初光能转化效率受到抑制,光合作用能力减弱,温度达到最低时光抑制明显,一旦胁迫缓解,叶片光合能力有所恢复;温州绿竹光能转化效率较高,具有较强抗低温能力,福安、尤溪绿竹居中,漳州绿竹抗寒性最弱。

Dynamics of chlorphyll fluorescence parameters of Bambusa oldhamii from different producing areas in overwintering

The dynamics of chlorophyll fluorescence parameters were mensurated on leaves of Bambusa oldhamii Munro from four producing areas in overwintering,the adaptive mechanism of bamboo against low temperature and the difference of responses from different original were discussed.It shows that initial fluorescence yield(F0) and non-photochemical quenching coefficient(qN) are slightly higher in overwintering,while maximum fluorescence yield(Fm),variable fluorecence yield(Fv),maximum photochemical efficiency of PSⅡ(Fv/Fm),potential activity of PSⅡ(Fv/F0),photochemical quenching coefficient(qP),actual photochemical efficiency of PSⅡ(ΦPSⅡ) are affected by temperature,the dynamics of which is the same as monthly mean temperature,i.e.decreased first and increase behind.It is speculated that self-protective mechanism comes into being through regulating photosynthesis under cold stress,i.e.with the enhancement of cold stress,the potential activity and efficiency of primary conversion of light energy of PSⅡ,are inhibited,the photosynthesis capacity are decreased,photoinhibition is the most significant in the lowest temperature,and leaf photosynthetic capacity can be recovered while the stress relieved.Meanwhile the conversion efficiency of B.oldhamii from Wenzhou is higher which has the strongest ability to resist low temperature,followed by B.oldhamii from Fu′an and Youxi,and B.oldhamii from Zhangzhou has the lowest ability to resist low temperature.