碳量子点对模式植物拟南芥的生物效应研究

以模式植物拟南芥（Arabidopsis thaliana（L.）Heynh）为材料，从生理及分子层面研究碳量子点（Carbon quantum dots，CQDs）对拟南芥生物效应的影响。结果显示，CQDs能被拟南芥根部吸收并连续运输到叶片，对种子萌发率无明显影响，但能显著促进幼苗主根伸长和株重的增加。幼苗叶片叶绿体中色素含量随CQDs浓度的升高而显著降低。脯氨酸与丙二醛含量随CQDs浓度的升高呈先上升后下降趋势。超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性随CQDs浓度的升高呈先上升后下降趋势，在抗氧化酶系统中起主导作用；叶片内源过氧化氢（H₂O₂）的积累随CQDs浓度的升高而升高，具有显著的浓度依赖效应。与其他纳米材料处理不一样的是，硫同化及胁迫相关基因在CQDs处理后表达量下调，这可能与CQDs粒子本身的特性有关。

Biological effects of carbon quantum dots on model plant Arabidopsis thaliana

Based on the model plant Arabidopsis thaliana (L.) Heynh, we studied the biological effects of carbon quantum dots (CQDs), a new nanomaterial, and investigated their distribution and transportation, effects on growth and development, photosynthetic pigment content, oxidative stress, and stress-related gene expression levels in A. thaliana. Results showed that CQDs could be absorbed by the roots of A. thaliana and transported continuously to the leaves, which had no significant effect on seed germination rate, but significantly promoted the growth of seedling roots and plant weight. With the increase in CQD concentration, the pigment content in the chloroplast of seedlings decreased significantly, whereas the content of proline and malondialdehyde increased at first and then decreased. Superoxide dismutase (SOD) and catalase (CAT) played a leading role in the antioxidant enzyme system, and showed increasing and then decreasing activity as CQD concentration increased. The accumulation of endogenous hydrogen peroxide (H₂O₂) in leaves also indicated that CQDs could induce oxidative stress with concentration-dependent effects. Sulfur assimilation and stress-related genes were down-regulated after CQD treatment, which might be related to the characteristics of the CQD particles themselves. These results are of great significance for exploration of the molecular mechanisms of the bio-effects of nanomaterials on plants and for evaluating their biosafety.