Graphene quantum dots-induced physiological and biochemical responses in mung bean and tomato seedlings

Abstract

Different physiological and biochemical responses in mung bean (Vigna radiata L.) and tomato (Solanum lycopersicum L.) seedlings induced by graphene quantum dots (GQDs) (250-1500 mg L −1) were studied. Results showed that both seeds exposed to GQDs can still germinate normally. However, the growth of the seedlings after germination was adversely affected by the GQDs, and mung bean was more sensitive than tomato. In hydroponic experiments, the appropriate concentration of GQDs enhanced the accumulation of chlorophyll in mung bean (250-1250 mg L −1) and tomato (250-500 mg L −1) seedlings after exposure for 2 weeks. High concentrations of GQDs (1000-1500 mg L −1) led to an increase in the H 2 O 2 , malondialdehyde (MDA), proline, glutathione (GSH) levels, as well as increased catalase (CAT) and glutathione reductase (GR) activities in seedlings of both species. In addition, the migration of GQDs into plants was observed. Results showed that high concentrations of GQDs had an adverse effect on the growth of both plants, and mung bean seedlings were more sensitive than tomato seedlings. In addition, the problem of nanocontamination was suggested and the resulting food safety problems warrant further investigation.

Putrescine-functionalized carbon quantum dot (put-CQD) nanoparticles effectively prime grapevine (Vitis vinifera cv. ‘Sultana’) against salt stress

“…Iron-NPs were also shown to enhance proline content of grapevine under control and salinity conditions [ 31 ]. This enhancement was reported following QD application, as well [ 45 ], in accordance with the current study.…”

“…Exogenous application of PAs decreased MDA levels in plants under salinity [ 24 , 26 , 27 , 44 ]. Furthermore, graphene QD application at low doses decreased MDA content [ 45 ]. Mozafari et al [ 31 ] observed similar mitigating effect of iron-NPs on decreasing MDA content of grapevine under salinity.…”

Putrescine-functionalized carbon quantum dot nanoparticles (Put-CQD) effectively prime grape (Vitis vinifera cv. Sultana) against salt stress

“…Exogenous application of PAs decreased MDA levels in plants under salinity [24,26,27,44]. Furthermore, graphene QD application at low doses decreased MDA content [45]. Mozafari et al [31] observed similar mitigating effect of iron-NPs on decreasing MDA content of grapevine under salinity.…”

“…In terms of the effect of nanomaterials, iron-NPs enhanced APX, SOD and POD enzymatic activities of grapevine under salinity conditions [31]. Feng et al [45] reported enhanced CAT activity at lower graphene QD concentration, likely due to enhanced oxidative stress that reduces biosynthesis of antioxidant enzymes like CAT. Gohari et al [12,13] reported positive effect of MWCNTs-COOH and TiO 2 NPs on SOD, CAT, APX and GP enzymatic activities under both control and salt stress conditions, in line with the current nding.…”

“…Most phenolics are stimulated under biotic and abiotic stresses (Lim et al, 2015), such as under salinity conditions [52]. Feng et al [45] reported increased phenolics following application of low concentration of QDs. In addition, MWCNTs-COOH treatment enhanced plant phenolics under salinity conditions [12].…”