Bio-synthesized calcium carbonate (CaCO3) nanoparticles: Their anti-fungal properties and application as nanofertilizer on Lycopersicon esculentum growth and gas exchange measurements

Abstract

Bio-synthesized calcium carbonate nanoparticles (CaCO3 NPs) have gained attention because of their cost-effectiveness, minimal toxicity, biological compatibility, cytological compatibility, pH sensitivity, gradual biological degradability and ecological friendliness. As the global population is expected to rise to billions, innovative strategies to enhance crop production are necessary to address poverty challenges. This study assesses the effect of the bioinspired CaCO3 NPs as nanofertilizers on the development, gas exchange and yield parameters of tomatoes (Lycopersicon esculentum) and their antifungal activity. The trial was conducted in a 2×4 completely randomised design (CRD) with four replicates. The treatments consisted of different CaCO3 NPs concentrations (Control = 0 mg/L, 50 mg/L, 150 mg/L and 250 mg/L) on two tomato cultivars (Money-maker and Heinz-1370), and the antifungal activity of the CaCO3 NPs was tested against pathogens that cause diseases in tomato plants. The results demonstrate that CaCO3 NPs exhibit moderate antifungal activity against Cladosporium cladosporioides, Fusarium oxysporum and Penicillium halotolerans at minimum inhibitory concentration (MIC) values of 125, 250 and 500 µg/mL. Results further show that 250 mg/L exhibits the highest number of leaves on Money-maker, while 150 mg/L gave the highest number of leaves at week 8 for Heinz-1370. The application of 150 mg/L yielded the highest number of flowers in both cultivars compared to other treatments. Remarkably, different CaCO3 NP concentrations varied the gas exchange parameters and revealed that at concentrations higher than 150 mg/L, the efficiency of water use during the vegetative and fruiting stages was lowered. The highest fruit weight of the Money-maker was observed at 50 mg/L, whereas Heinz-1370’s fruit weight was higher at 250 mg/L, indicating that the two cultivars are affected differently by the foliar application of CaCO3 NPs. Therefore, the findings of this study suggest that the inclusion of a green synthesis of CaCO3 NPs as a nanofertilizer has the potential to promote tomato growth and yield.