Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. Georgi Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria.
Faculty of Biology, Sofia University 'St. Kliment Ohridski', 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria.
Molecules. 2021 Oct 1;26(19):5958. doi: 10.3390/molecules26195958.
Single-walled carbon nanotubes (SWCNT) have recently been attracting the attention of plant biologists as a prospective tool for modulation of photosynthesis in higher plants. However, the exact mode of action of SWCNT on the photosynthetic electron transport chain remains unknown. In this work, we examined the effect of foliar application of polymer-grafted SWCNT on the donor side of photosystem II, the intersystem electron transfer chain and the acceptor side of photosystem I. Analysis of the induction curves of chlorophyll fluorescence via JIP test and construction of differential curves revealed that SWCNT concentrations up to 100 mg/L did not affect the photosynthetic electron transport chain. SWCNT concentration of 300 mg/L had no effect on the photosystem II donor side but provoked inactivation of photosystem II reaction centres and slowed down the reduction of the plastoquinone pool and the photosystem I end acceptors. Changes in the modulated reflection at 820 nm, too, indicated slower re-reduction of photosystem I reaction centres in SWCNT-treated leaves. We conclude that SWCNT are likely to be able to divert electrons from the photosynthetic electron transport chain at the level of photosystem I end acceptors and plastoquinone pool in vivo. Further research is needed to unequivocally prove if the observed effects are due to specific interaction between SWCNT and the photosynthetic apparatus.
单壁碳纳米管 (SWCNT) 最近作为一种调节高等植物光合作用的有前途的工具引起了植物生物学家的关注。然而，SWCNT 对光合作用电子传递链的确切作用模式仍不清楚。在这项工作中，我们研究了聚合物接枝 SWCNT 对光系统 II 的供体侧、电子传递链和光系统 I 的受体侧的叶面应用的影响。通过 JIP 测试分析叶绿素荧光的诱导曲线和构建差分曲线表明，高达 100mg/L 的 SWCNT 浓度不会影响光合作用电子传递链。300mg/L 的 SWCNT 浓度对光系统 II 供体侧没有影响，但会引起光系统 II 反应中心失活，并减缓质醌库和光系统 I 末端受体的还原。820nm 调制反射的变化也表明，SWCNT 处理叶片中光系统 I 反应中心的再还原速度较慢。我们得出结论，SWCNT 很可能能够在体内将电子从光系统 I 末端受体和质醌库水平从光合作用电子传递链中转移出来。需要进一步的研究来明确证明观察到的效应是否是由于 SWCNT 与光合作用装置之间的特定相互作用。
