Promoting the Growth of Mung Bean Plants through Uptake and Light Conversion of NaYF₄:Yb,Er@CDs Nanocomposites

Abstract

In recent years, the application of nanomaterials in promoting plant growth and augmenting photosynthesis has aroused great interest. Herein, carbon dots (CDs) are combined with NaYF4:Yb,Er to achieve an enhanced upconversion red emission. The effects of the obtained NaYF4:Yb,Er@CDs nanocomposites on the growth of mung bean plants are investigated. It is found that an appropriate concentration of the NaYF4:Yb,Er@CDs nanocomposites (0.5 mg/mL) can enhance the water absorption ability of hydroponic mung beans and promote their growth after incubation for 7 days. Confocal imaging shows that the nanocomposites can transfer from the roots to the stems and leaves. Interestingly, after spraying the nanocomposite solution on the surface of the mung bean seedling leaves and placing them under sunlight for 2 weeks, the root/stem lengths and wet/dry weight clearly increase. Moreover, the photosynthetic rate of the mung bean seedling is found to increase by more than 2 times, while the transpiration rate and stomatal conductance are improved by 144 and 148%, respectively. Such a promoting effect is ascribed to the ability of the NaYF4:Yb,Er@CDs nanocomposites to convert near-infrared (NIR) radiation into red light, which is beneficial for plant photosynthesis. This work provides a promising strategy for promoting plant growth by the application of nanomaterials.

Carbon-Based Nanomaterials for Sustainable Agriculture: Their Application as Light Converters, Nanosensors, and Delivery Tools

“…Carbon nanomaterials can work with up-conversion optical materials to promote nIR light conversion to enhance plant photosynthesis [101,102]. Doping CDs into the up-conversion material NaYF4: Yb, Er, CDs can shift the green emission of NaYF4: Yb, Er to red light [103]. Mung beans sprayed with NaYF4: Yb, Er@CD nanocomposite showed a significantly increased photosynthetic rate [103].…”

Nanomaterials as Nanofertilizers and Nanopesticides: An Overview

“…[58] In the study by Xu et al NaYF4:Yb,Er combined with CDs showed efficiently an increase in the length of root/stem as well as the weight of dry/wet of mung bean seedlings by using spraying these nanocomposites. [59] In another research by Aji et al [60] the beneficial influence of CDs exhibited in enhancement of plant growth of Ipomoea aquatic. In this study, the CDs derived from the peels of dragon fruit not only acted as nutrients carrier of nitrogen-phosphor-potassium (NPK) fertilizer but also were as supplementation in the enhancement of plant growth.…”

Influence of Luminescent Nanomaterials on Plant Growth and Development

“…This is the first report on employing the unique dual‐emission trait to augment plant photosynthesis. In 2020, this research team prepared far‐red CDs that can convert ultraviolet light into far‐red emission [57] (Figures 7a, 7b) and NaYF 4 :Yb,Er@CDs nanocomposites that can convert NIR irradiation into red light (Figures 7c, 7d) [58] …”