干旱胁迫下德景天叶片超微弱发光与活性氧的关系

The relationship between ultraweak luminescence and reactive oxygen under drought stress in the Sedum hybridum leaf

以德景天为试材,研究其在聚乙二醇(PEG6000)模拟干旱胁迫处理及施加过氧化氢(H_2O_2)和苯甲酸钠处理PEG模拟干旱胁迫下的超微弱发光(UWL)和活性氧的变化及二者之间的关系。结果表明,在干旱胁迫过程中,PEG处理和对照的德景天叶片超氧阴离子(O_2^-)产生速率、丙二醛(MDA)含量和相对电导率均持续上升,UWL均下降;在整个干旱胁迫过程中,PEG处理的O_2^-产生速率、MDA含量和相对电导率均高于对照,UWL强度均低于对照。施加H_2O_2和苯甲酸钠处理PEG模拟干旱胁迫过程中,PEG+H_2O_2处理、PEG+苯甲酸钠处理和PEG处理(对照)的O_2^-产生速率、MDA含量和相对电导率均持续上升,UWL均下降。在整个干旱胁迫过程中,H_2O_2处理的O_2^-产生速率、MDA含量和相对电导率均高于对照,苯甲酸钠处理后三者均低于对照;H_2O_2处理的UWL强度均低于对照,苯甲酸钠处理的UWL强度均高于对照。在德景天干旱胁迫及活性氧处理干旱胁迫过程中,UWL强度均随着活性氧的积累而下降;干旱胁迫下,施加H_2O_2处理加剧了活性氧的上升积累,同时加剧了UWL强度下降;施加苯甲酸钠处理缓减了活性氧的上升积累,同时缓减了UWL强度的下降。以上结果说明,干旱胁迫引发UWL强度降低,活性氧积累不是引起UWL变化的主要来源。有可能活性氧是UWL的来源之一,但存在其他因素对UWL的影响更强,导致活性氧的变化并不能体现UWL的变化趋势。

The dynamic variation of ultraweak luminescence （UWL） and its relationship with reactive oxygen were studied during the simulated drought stress with PEG6000 solution and？hydrogen peroxide （H2O2） treatment, and sodium benzoate treatment under the PEG simulated drought stress process in Sedum hybridum. The results showed that the superoxide anion radical（O2-）production rate, malondialdehyde （MDA） content and relative electric conductivity of the PEG treatment and CK in the drought stress process increased continually, while the UWL intensity decreased. Meanwhile, the O2- production rate, MDA content and relative electric conductivity of the PEG treatment were all higher than those of CK except that the UWL intensity was lower than that of CK in the whole drought stress process. During H2O2 treatment and sodium benzoate treatment under the PEG simulated drought stress process, the O2- production rate, MDA content and relative electric conductivity under PEG＋H2O2 treatment, PEG＋sodium benzoate treatment and PEG （CK） increased continually, while the UWL intensity decreased. In whole drought stress process, the O2- production rate, MDA content and relative electric conductivity under H2O2 treatment were all higher than those of CK, except that the UWL intensity was lower than that of CK. However, the O2- production rate, MDA content and relative electric conductivity under benzoate treatment were all lower than those of CK, except that the UWL intensity was higher than that of CK. During the PEG simulated drought stress with H2O2 treatment and sodium benzoate treatment under the simulated drought.stress process in Sedum hybridum, UWL intensity decreased with the accumulation of active oxygen. H202 treat- ment aggravated the accumulation of reactive oxygen as well as the decline of UWL. Sodium benzoate treatment slowed down the accumulation of reactive oxygen as well as the decline of UWL. Based on the results, we con- cluded that drought stress could cause the decrease of UWL intensity, and the accumulation of reactive oxygen species was not the main source of UWL. It is possible that reactive oxygen species is one of the sources of UWL, but other factors have more influence on UWL, and the change of reactive oxygen species could not reflect the change trend of UWL.