The impact of carbon dot nanomaterials on two cultivars of common wheat

Abstract

We are, without a doubt, facing some of the biggest agricultural challenges to date, with projected increases in crop demands and climate change severely threatening crop production. Furthermore, current projected increases in crop yields are not high enough to meet demand in the coming decades. Historically, agricultural intensification has increased crop yields, yet current agricultural practices are unsustainable and contribute to environmental destruction. Therefore, there is a pressing need for new technologies to aid in sustainably intensifying agriculture. Carbon dot (CD) nanomaterials have been presented as sustainable biostimulants, able to enhance nutrient uptake and use efficiency in plants; herein, their effects on two cultivars of common wheat, Triticum aestivum cv. Apogee and Paragon, are investigated. Firstly, confocal microscopy confirmed successful uptake of CDs from soil. Then, CDs were revealed to significantly increase photosynthetic activity in a number of ways; the chlorophyll contents of flag leaves was increased and the expression of chlorophyl a-b binding proteins was upregulated, increasing light-harvesting capacity; oxygen-evolving enhancer proteins were upregulated, and the rate of electron transport was significantly increased; the rate of non-photochemical quenching (NPQ) was decreased and NPQ-related genes were down-regulated; and photoprotective mechanisms were up-regulated, including increased flavanol production, ROS scavenging, and modulated photosystem stoichiometry, shown by the up-regulation of photosystem I genes and down-regulation of photosystem II genes. Importantly, dual application of CDs and NPK fertilisers enhanced crop yields and ear development, more so than CD or fertiliser treatment alone. Overall, CDs are a promising biostimulant candidate for use in agriculture and enhance NPK fertiliser use. Further work is needed to quantify the optimum concentrations of CDs and NPK fertilisers, and with optimum concentrations likely to be cultivar-dependent, further work is needed to assess how best to tailor application to a wider range of wheat cultivars.

Date of Award	6 Dec 2022
Original language	English
Awarding Institution	University of Bristol
Supervisor	Heather M Whitney (Supervisor) & Keara A Franklin (Supervisor)