| With the progress of science and technology and the rapid development of nanotechnology,the application of nanomaterials has been more and more concerned by human beings,in the industrial field of nanomaterials has been very good application and development.Carbon quantum dots(CDs)were used to investigate whether nanomaterials could also be used in agriculture and environmental protection,such as promoting plant growth(including promoting plant growth in adverse conditions),biological imaging and other related aspects.Carbon quantum dots(CDs)are a new kind of nanomaterials.Because of their small size and excellent water solubility,they can be absorbed by the roots of plants with water.To refine the study,we synthesized two metal doped carbon quantum dots:Magnesium nitrogen co-doped carbon quantum dots(Mg-N-CDs)and cerium-nitrogen co-doped carbon quantum dots(Ce-N-CDs).First,Mg and N co doped carbon quantum dots(Mg-N-CDs)as an example to research the Arabidopsis thaliana.The effects of Mg-N-CDs on the growth and development of A.thaliana was examined.The absorption and distribution of Mg-N-CDs in A.thaliana roots and leaves and the relative expression levels of related genes(E2Fa and Histone H4)in the cell cycle of A.thaliana seedlings were also determined.Results showed that Mg-CDs could accelerate the growth of A.thaliana roots.They were widely distributed in the cell wall and cytoplasm of the roots and chloroplasts of the leaves,and the relative expression levels of E2Fa increased first and then decreased with the increase in Mg-N-CDs concentration,as did that of H4.Further analysis indicated that Mg-N-CDs affected the cell cycle of A.thaliana seedlings,thus resulting in root elongation,which may be due to the shortened cell cycle,resulting in more cell division,thereby promoting root length.These results indicate that Mg-N-CDs has great application potential in promoting plant growth.In addition,we also designed its effect on plant growth under UV-B radiation.UV-B radiation can affect plant growth and cause damage to plants.We explored the bioimaging and mitigation of UV-B damage of Mg-N-CDs.Mg-N-CDs has low toxicity,stability and good biocompatibility.Under UV-B radiation(10.08 KJ/m~2/d),root length and plant height of wheat seedlings were inhibited by 39.8%and 57.4%,fresh weight decreased by 35.3%,total chlorophyll content decreased by 30%,and SOD,POD and CAT activities in wheat leaves were also decreased.When Mg-N-CDs was applied to wheat seedlings exposed to UV-B,the above indexes were significantly restored and the defense enzymes were activated,which enhanced the antioxidant effect of wheat.We also analyzed genes related to glutathione synthesis,and the expression of ATPS decreased by 31.6%after UV-B treatment.The expression of ATPS was upregulated after the addition of Mg-N-CDs.Mg-N-CDs also upregulates the expression of glutathione related genes(CS and GS)to enhance the antioxidant capacity of plants,which plays a positive role in improving the UV-B radiation damage of wheat.This finding confirms the potential of Mg-N-CDs to enhance plant intrinsic functions,such as antioxidant and photosynthesis,and enhance plant tolerance to environmental stress.Therefore,Mg-N-CDs can be used as a regulator to reduce UV-B damage to plants,laying a foundation for its application in environmental protection and agricultural production.These results indicate that Mg-N-CDs can not only promote root growth,but also be used as a regulator,which has great application potential in the agricultural field.Cerium–Nitrogen co–doped carbon quantum dots(Ce-N-CDs),a novel type of carbon-based nanomaterials,are prepared using hydrothermal synthesis.Ce-N-CDs demonstrate low toxicity,stability,and satisfactory biocompatibility.Effects of Ce-N-CDs on Arabidopsis root growth were analyzed at physiological and molecular levels in this study.Ce-N-CDs(0.04 mg/m L)promoted the growth of primary root(PR)and root tip meristem(RAM).Ce-N-CDs effectively regulated the expression of cell cycle-related genes and promoted the growth of PR and RAM by enhancing cell division capacity of the RAM and activity of stem cells niche.The expression of auxin synthesis genes was upregulated after treatment with Ce-N-CDs,and the increased abundance of auxin transporters PIN1,PIN2,and PIN7 led to the increased accumulation of auxin and promotion of root growth.Thus,Ce-N-CDs can potentially promote plant growth and bioimaging.Therefore,Ce-N-CDs has potential value in promoting plant growth and biological imaging.In summary,these results lay a foundation for the application of nanomaterials in agricultural production,environmental protection and biological imaging. |
