三种不同衰老类型牡丹叶片叶绿素荧光特性的比较

以三种不同衰老类型的牡丹品种卷叶红、大胡红和肉芙蓉为试材,比较其叶片在不同时期的强光下叶绿素荧光特性的差异,探讨牡丹叶片光抑制发生的机理和叶片衰老差异的原因。结果显示,7月中旬至8月下旬,与大胡红和肉芙蓉相比,卷叶红的PSⅡ最大光化学效率(Fv/Fm)、PSⅡ电子传递量子产率(PSⅡ)和光化学猝灭系数(qP)下降较小,且保持了较高的非光化学猝灭系数(NPQ)。表明叶黄素循环的热耗散迅速增加,提高了对强光的适应,而可逆失活和不可逆破坏则加重了光合机构的损伤,这造成了衰老的先后次序为肉芙蓉、大胡红、卷叶红。Fv/Fm、NPQ、qP和PSⅡ对光强响应的差异明显,使之可以作为鉴定耐光抑制能力大小的指标。

Comparison of Chlorophyll Fluorescence Characters in Tree Peony Leaves among Three Different Senescence Types

Using three tree peony cultivars with different senescence types,Juanyehong(J),Dahuhong(D) and Roufurong(R),the experiment was performed to compare the chlorophyll fluorescence characters in their leaves during different periods,and investigate the possible mechanism of photoinhibition and the causes of leaf senescence at different stages.Compared with Dahuhong and Roufurong,the maximum photochemical efficiency of PSⅡ(Fv/Fm),the quantum efficiency of electron transport of PSⅡ(PSⅡ) and photochemical quenching coefficient(qP) of Juanyehong descended the lest while its non-photochemical quenching coefficient(NPQ) was the highest in later August.Changes of chlorophyll fluorescence parameters showed xanthophyll cycle was enhanced rapidly and the adaptation to strong radiation increased,but reversible inactivation and irreversible damage aggravated the damage of photosynthetic apparatus.As a result,the senescence order of three tree peony was Roufurong,Dahuhong,Juanyehong.The significant differences of Fv/Fm,NPQ,qP and FPSⅡ in response to strong light among different cultivars showed that they might serve as the reference indices to evaluate the light-resistant capacity.