盐胁迫下德景天叶片超微弱发光与光合作用的关系

以德景天(Sedum hybridum)为材料,分析NaCl胁迫及活性氧调控NaCl胁迫下德景天叶片UWL与光合作用的变化及两者之间的关系。结果表明,在盐胁迫过程中,对照和盐胁迫下景天叶片的净光合速率(P_n)、蒸腾速率(T_r)、气孔导度(G_s)、胞间二氧化碳浓度(C_i)和叶绿素a(Chla)、叶绿素b(Chlb)和叶绿素总量(Chl)均呈下降趋势,同时UWL强度下降;盐胁迫下以上光合指标均低于对照,同时UWL强度也低于对照。进一步采用H_2O_2和苯甲酸钠处理盐胁迫过程中,NaCl处理(对照)、NaCl+H_2O_2处理和NaCl+苯甲酸钠处理下景天叶片的P_n、T_r、G_s、C_i、Chla、Chlb和Chl均下降,同时UWL强度下降;H_2O_2处理的以上光合指标均低于对照,UWL强度也低于对照;苯甲酸钠处理的光合指标和UWL强度均高于对照。相关性分析也表明,盐胁迫下及活性氧处理盐胁迫下UWL强度均与各光合指标呈明显正相关。结果说明,盐胁迫下及活性氧处理盐胁迫下,UWL强度随着景天叶片光合作用的下降而降低,光合作用与UWL的产生有关。

The relationship between ultraweak luminescence and photosynthesis under salt stress of Sedum hybridum

The study was to investigate the relationship between the change of ultraweak luminescence (UWL) and photosynthetic characteristics under NaCl stress and the active oxygen-regulated NaCl stress in Sedum hybridum. The results showed that: in the process of salt stress, the net photosynthetic rate (P_n), transpiration rate (T_r), stomatal conductance (G_s), intercellular carbon dioxide (C_i) and chlorophyll a (Chla), chlorophyll b (Chlb), chlorophyll (Chl) continued to decline; meanwhile, the UWL intensity was decreasing too. All aforementioned photosynthetic characteristics and UWL intensity under salt stress were lower than those of CK. In the salt stress regulated by H₂O₂ and sodium benzoate, P_n, T_r, G_s, C_i, Chla, Chlb and Chl treated with NaCl (CK), NaCl+ H₂O₂, NaCl+sodium benzoate were all decreased and the UWL intensity was also decreased. These photosynthetic characteristics and UWL intensity treated with NaCl+ H₂O₂ were lower than those of CK, while those treated with NaCl+ sodium benzoate were higher than those of CK. Correlation analysis showed that there was a significant positive correlation between UWL intensity and photosynthesis under both the salt stress and reactive oxygen-regulated salt stress. The results indicated that UWL intensity decreased along with the decline of photosynthesis under salt stress, which indicated that photosynthesis should play a role in source and generation of UWL.