Department of Molecular Biology and Genetics, Faculty of Science, Necmettin Erbakan University, 42090, Konya, Turkey.
Department of Biotechnology, Faculty of Science, Selcuk University, 42130, Konya, Turkey.
Chemosphere. 2024 May;356:141937. doi: 10.1016/j.chemosphere.2024.141937. Epub 2024 Apr 8.
Based on their chemical structure and catalytic features, carbon dots (CDs) demonstrate great advantages for agricultural systems. The improvements in growth, photosynthesis, nutrient assimilation and resistance are provided by CDs treatments under control or adverse conditions. However, there is no data on how CDs can enhance the tolerance against chromium toxicity on gas exchange, photosynthetic machinery and ROS-based membrane functionality. The present study was conducted to evaluate the impacts of the different concentrations of orange peel derived-carbon dots (50-100-200-500 mg L CD) on growth, chlorophyll fluorescence, phenomenological fluxes between photosystems, photosynthetic performance, ROS accumulation and antioxidant system under chromium stress (Cr, 100 μM chromium (VI) oxide) in Lactuca sativa. CDs removed the Cr-reduced changes in growth (RGR), water content (RWC) and proline (Pro) content. Compared to stress, CD exposures caused an alleviation in carbon assimilation rate, stomatal conductance, transpiration rate, carboxylation efficiency, chlorophyll fluorescence (F/F) and potential photochemical efficiency (F/F). Cr toxicity disrupted the energy fluxes (ABS/RC, TR/RC, ET/RC and DI/RC), quantum yields and, efficiency (ΨE and φR), dissipation of energy (DI/RC) and performance index (PI and PI). An amelioration in these parameters was provided by CD addition to Cr-applied plants. Stressed plants had high activities of superoxide dismutase (SOD), peroxidase (POX) and ascorbate peroxidase (APX), which could not prevent the increase of HO and lipid peroxidation (TBARS content). While all CDs induced SOD and catalase (CAT) in response to stress, POX and enzyme/non-enzymes related to ascorbate-glutathione (AsA-GSH) cycle (APX, monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR), the contents of AsA and, GSH) were activated by 50-100-200 mg L CD. CDs were able to protect the AsA regeneration, GSH/GSSG and GSH redox status. The decreases in HO content might be attributed to the increased activity of glutathione peroxidase (GPX). Therefore, all CD applications minimized the Cr stress-based disturbances (TBARS content) by controlling ROS accumulation, antioxidant system and photosynthetic machinery. In conclusion, CDs have the potential to be used as a biocompatible inducer in removing the adverse effects of Cr stress in lettuce plants.
基于其化学结构和催化特性，碳点（CDs）在农业系统中显示出巨大的优势。在控制或不利条件下，CD 处理可提高生长、光合作用、养分吸收和抗性。然而，关于 CD 如何增强对铬毒性的耐受性，即在气体交换、光合作用机制和基于 ROS 的膜功能方面的耐受性，尚无数据。本研究旨在评估不同浓度的橙皮衍生碳点（50-100-200-500mg/L CD）对生菜生长、叶绿素荧光、光系统间表型通量、光合作用性能、ROS 积累和抗氧化系统的影响铬胁迫（Cr，100μM 六价铬氧化物）。CDs 去除了 Cr 降低的生长（RGR）、水分含量（RWC）和脯氨酸（Pro）含量的变化。与胁迫相比，CD 暴露导致碳同化率、气孔导度、蒸腾速率、羧化效率、叶绿素荧光（F/F）和潜在光化学效率（F/F）的缓解。Cr 毒性破坏了能量通量（ABS/RC、TR/RC、ET/RC 和 DI/RC）、量子产率和效率（ΨE 和 φR）、能量耗散（DI/RC）和性能指数（PI 和 PI）。添加 CD 可改善这些参数。受胁迫的植物具有高的超氧化物歧化酶（SOD）、过氧化物酶（POX）和抗坏血酸过氧化物酶（APX）活性，但不能阻止 HO 和脂质过氧化（TBARS 含量）的增加。虽然所有 CDs 都能诱导 SOD 和过氧化氢酶（CAT）对胁迫的反应，但 POX 和与抗坏血酸-谷胱甘肽（AsA-GSH）循环相关的酶/非酶（APX、单脱氢抗坏血酸还原酶（MDHAR）和脱氢抗坏血酸还原酶（DHAR）、AsA 和 GSH 的含量）被 50-100-200mg/L CD 激活。CDs 能够保护 AsA 的再生、GSH/GSSG 和 GSH 氧化还原状态。HO 含量的降低可能归因于谷胱甘肽过氧化物酶（GPX）活性的增加。因此，所有 CD 的应用都通过控制 ROS 积累、抗氧化系统和光合作用机制，最大限度地减少了 Cr 胁迫引起的干扰（TBARS 含量）。总之，CDs 具有作为生物相容性诱导剂的潜力，可消除生菜植物中 Cr 胁迫的不利影响。
