Tomato plant (Solanum lycopersium Mill.) is among the highly cultivated vegetable crops worldwide. With the increase in cadmium (Cd)-polluted area, the risk of tomato safe production has increased. Therefore,ahydroponic experiment was conducted to study the effects of silicon (Si) on the growth, nutrient uptake and Cd accumulation of tomato seedlings. Tomato seedlings were grown in Yamazaki’s nutrient solutionwith fourdifferent Cd levels (0.5, 1, 2 and 3 mg/L) along with four Si treatment levels (0, 1, 2 and 3 mmol/L). The results showed that the addition of Si improved the growth and activities of antioxidant enzymes (SOD and CAT) as well as the nutrient uptake (Ca, Mg, Fe, Mn and Zn) of tomato seedlings under different Cd exposure levels compared to Cd treatment alone. The addition of Si decreased the Cd content in the roots and shoots of tomato seedlings, and the Cd content in the roots and shoots was lowest when the Si concentration was 3 mmol/L. In conclusion, the negative effect of Cd on the growth of tomato seedlings was alleviated by Si-induced increases in biomass, activities of antioxidant enzymes and nutrient uptake and inhibition of Cd uptake.

As a globally significant economic crop, pepper (Capsicum annuum L.) plants display excessive plant height (etiolation) in greenhouse production under an undesirable environment, leading to lodging-prone plants with reduced stress resistance. In the present study, we provided supplementary ultraviolet-B (UV-B, 280–315 nm) light to pepper plants grown in a greenhouse to assess the influences of UV-B on pepper growth, with an emphasis on the molecular mechanisms mediated through the gibberellin (GA) signaling pathway. The results indicated that UV-B significantly decreased the plant height and the fresh weight of pepper plants. However, no significant differences were observed in the chlorophyll content of pepper plants grown under natural light and supplementary UV-B radiation. The results of the transcriptomic and metabolomic analyses indicated that differentially expressed genes (DEGs) were significantly enriched in plant hormone signal transduction and that UV radiation altered the gibberellin synthesis pathway of pepper plants. Specifically, the GA3 content of the pepper plants grown with UV-B radiation decreased by 39.1% compared with those grown without supplementary UV-B radiation; however, the opposite trend was observed in GA34, GA7, and GA51 contents. In conclusion, UV-B exposure significantly reduced plant height, a phenotypic response mechanistically linked to an alteration in GA homeostasis, which may be caused by a decrease in GA3 content. Our study elucidated the interplay between UV-B and gibberellin biosynthesis in pepper morphogenesis, offering a theoretical rationale for developing UV-B photoregulation technologies as alternatives to chemical growth inhibitors.

Graphene oxide (GO) has shown great potential in agricultural applications, however, its concentration-dependent effects on cucumber (Cucumis sativus L.) growth, nutrient absorption, and root architecture remain unclear. In the present study, a hydroponic experiment was conducted with different GO concentrations (0.5, 1.0, and 2.0 mg L−1) and setting the non-GO treatment (0.0 mg L−1) as the control for cucumber plants (cv. Qingbaizao). The results showed that low to moderate concentrations (0.5–1.0 mg L−1) significantly promoted cucumber growth, increased shoot and root biomass, enhanced the accumulation of nitrogen, phosphorus, and potassium, and optimized root architecture by increasing cellulose and hemicellulose content. In contrast, high GO concentrations (2.0 mg L−1) exhibited significant inhibitory effects, reducing plant growth indicators, inhibiting nutrient accumulation, particularly in shoots, damaging root structure, and leading to obvious damage to root apical vascular bundles and disrupted the structural integrity of root tips. Further analysis revealed that the regulatory effect of GO on cucumber growth was closely related to its influence on root uptake capacity and root architecture optimization, as differentially expressed genes in ‘GO and Control’ comparison was remarkably enriched in phenylpanoid biosynthesis. This study systematically explores the concentration-dependent responses of cucumber growth, nutrient accumulation, and root architecture to GO, clarifies the suitable concentration range of GO for cucumber growth promotion, and provides theoretical basis and technical reference for the rational application of GO in cucumber cultivation.

Carbon dots (CDs) are promising nanomaterials for improving plant photosynthesis and growth, yet their regulatory roles under varied light regimes remain poorly elucidated. In this study, four treatments, namely natural light (Control), foliar application of carbon dots (CDs), shading (S), and shading combined with CDs (S-CDs), were established to investigate the impacts of foliar-applied CDs on leaf anatomy, photosynthetic performance, and biomass allocation in greenhouse-cultivated pepper (Capsicum annuum L. cv. Hongguan No.3) under different light regimes. Results showed that under natural light, CDs significantly increased the total chlorophyll content by 56.5% and palisade tissue thickness by 26.1%, while enhancing fruit yield by 34.4% without altering vegetative biomass. Shading alone triggered shade-avoidance responses (i.e., increased plant height and reduced leaf thickness), and reduced the net photosynthetic rate by 14.9% and fruit yield by 14.8%. Notably, the combined S-CDs treatment restored photosynthetic rate to control levels and improved fruit yield relative to shading alone, while maintaining shading-promoted morphological elongation and spongy tissue expansion. These findings demonstrate that foliar-applied CDs function as photosynthetic enhancers under normal-light conditions and light-compensatory agents under shading, via elevating the net photosynthetic rate and optimizing leaf anatomical structure. Our results provide new insights into the light-dependent regulatory roles of CDs in plant growth and offer a potential strategy for enhancing crop productivity under low-light conditions in protected cultivation.