利用快相叶绿素荧光参数综合评价3种丁香的耐盐性

A comprehensive evaluation of salt resistance in three clove varieties by the fast fluorescence transient parameters

以紫丁香(Syringa oblata)、白丁香(S.oblata var.alba)和暴马丁香(S.reticular var.mandshurica)为试验材料,利用快相叶绿素荧光技术研究了叶片光系统Ⅱ(PSⅡ)对盐胁迫的快速响应,并通过PSⅡ功能参数对丁香耐盐性进行了综合评价。结果表明:盐胁迫下3种丁香叶片的盐害表型特征和耐盐阈值与叶绿素荧光参数的变化趋势基本相符,随着盐浓度的增加,3种丁香叶片PSⅡ电子受体库容量降低,电子由Q A向Q B的传递过程受到抑制,最终导致PSⅡ向PSⅠ的电子传递能力降低,以吸收光能为基础的光合性能指数受到明显抑制。随着盐浓度的增加,3种丁香叶片的φD o和DI o/RC均呈增加趋势,即在盐胁迫下3种丁香叶片均可以通过增加热耗散的比例来降低激发能的产生,提高叶片的耐盐性,但过高的热耗散比例也降低了电子传递的能量比例(φE o和ET o/RC降低)。3种丁香叶片的各叶绿素荧光参数之间均存在显著或极显著的相关关系,通过隶属函数法对3种丁香叶片PSⅡ功能耐盐能力进行综合评价,结果发现盐胁迫下白丁香的PSⅡ功能耐盐性最强,暴马丁香次之,紫丁香最差。

Syringa oblata, S. oblata var. alba and S. reticular vat. mandshurica were used as test materials to investi- gate physiological reactions of photosystem Ⅱ in leaves under NaC1 stress using the fast fluorescence transients tech- niques. And a comprehensive appraisal of photosystem Ⅱ functions on the salt-tolerance was estimated in clove varie- ties. The results showed that the salt damage phenotypic characteristics and salt tolerance threshold values were basically the same as the trend of changes in chlorophyll fluorescence parameters in leaves of three clove. Along with the increas- ing of salt concentration, photosystem Ⅱ functions of three clove varieties were decreased, storage capacity PS Ⅱ elec- tronic receptors were reduced, and electrons from QA to QB were inhibited. The inhibitions leaded to a reduction on elec- tron transport from PSⅡ to PS I , and the photosynthetic performance index on energy absorption basis （PIAss ） was significantly inhibited. φDo and DIo/RC in leaves of three clove varieties showed an increasing trend. That was to say, the excitation energy could be reduced by increasing the ratio of heat dissipation in leaves of three clove varieties under salt stress, and the leaf salt-tolerance could be improved. However, the exorbitant ratio of heat dissipation also reduced the energy ratio of electron transport （ φEo and ETo/RC were decreased）. There were significant or highly significant cor- relations among different chlorophyll fluorescence parameters in leaves of three clove varieties. The subordinative fuzzy function was used to evaluate comprehensively salt tolerance, results showed that the ordination of salt-tolerance in photo- system 11 functions from high to low was as follow：S, oblata var. alba 〉 S. reticular var. mandshurica 〉 Syringa oblata.