Ptushenko V V, Ptushenko O S, Samoilova O P, Solovchenko A E
Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, 119234, Russia.
Biochemistry (Mosc). 2017 Jan;82(1):67-74. doi: 10.1134/S0006297917010072.
The kinetics of irradiation-induced changes in leaf optical transparence (ΔT) and non-photochemical quenching (NPQ) of chlorophyll fluorescence in Tradescantia fluminensis and T. sillamontana leaves adapted to different irradiance in nature was analyzed. Characteristic times of a photoinduced increase and a dark decline of ΔT in these species were 12 and 20 min, respectively. The ΔT was not confirmed to be the main contributor to the observed middle phase of NPQ relaxation kinetics (τ = 10-28 min). Comparison of rate of photoinduced increase in ΔT and photosystem II quantum yield recovery showed that the former did not affect the tolerance of the photosynthetic apparatus (PSA) to irradiances up to 150 µmol PAR·m·s. Irradiance tolerance correlated with the rate of "apparent NPQ" induction. Considering that the induction of apparent NPQ involves processes significantly faster than ΔT, we suggest that the photoprotective mechanism induction rate is crucial for tolerance of the PSA to moderate irradiance during the initial stage of light acclimation (first several minutes upon the onset of illumination).
分析了紫露草和银毛紫露草叶片在自然条件下适应不同光照强度时，辐射诱导的叶片光学透明度变化（ΔT）和叶绿素荧光非光化学猝灭（NPQ）的动力学。在这些物种中，光诱导的ΔT增加和暗下降的特征时间分别为12分钟和20分钟。未证实ΔT是观察到的NPQ弛豫动力学中间阶段（τ = 10 - 28分钟）的主要贡献因素。光诱导的ΔT增加速率与光系统II量子产率恢复速率的比较表明，前者对光合机构（PSA）在高达150 μmol PAR·m·s光照强度下的耐受性没有影响。光照耐受性与“表观NPQ”诱导速率相关。考虑到表观NPQ的诱导涉及比ΔT快得多的过程，我们认为光保护机制诱导速率对于光适应初始阶段（光照开始后的最初几分钟）光合机构对中等光照强度的耐受性至关重要。
