Rapid investigation of the alteration in biochemical profile of maize seedlings treated with aluminium oxide nanoparticles using spectroscopic techniques

[Display omitted] •Assessed the potential of spectroscopic techniques for rapid and non-destructive evaluation of the impact of Al2O3 NPs on maize plants.•The fluorescence and ultraviolet–visible spectroscopic analysis show a decrease in photosynthetic pigments, indicating toxicity of Al2O3 NPs.•The confocal micro-Raman measurements show a decrease in biochemicals, revealing negative effects of treated NPs on plants.•The results show that Al2O3 NPs exert an inhibiting effect on maize plants in a dose-dependent manner.•The study highlights that spectroscopic techniques can be used to monitor crop health status effectively and before the stress manifest visibly. The present study demonstrates the applicability of non-destructive and rapid spectroscopic techniques, specifically laser-induced fluorescence, ultraviolet–visible, and confocal micro-Raman spectroscopy, as non-invasive, eco-friendly, and robust multi-compound analytical methods for assessing biochemical changes in maize seedling leaves resulting from the treatment of aluminium oxide nanoparticles. The recorded fluorescence spectrum of the leaves shows that the treatment of different concentration of aluminium oxide nanoparticles decreases the chlorophyll content as observed by the increase in fluorescence emission intensity ratio (FIR = I685/I734). The analysis of ultraviolet–visible absorption measurements reveals that the amount of chlorophyll a, chlorophyll b, total chlorophyll and carotenoid decrease for treated plants with respect to untreated seedlings. Likewise, the analysis of the acquired Raman spectrum depicts that the treatment of different concentration of aluminium oxide nanoparticles exhibits toxic effect on the maize plants and reduces the level of biochemicals like cellulose, carbohydrates, carotenoid, lignin, proteins, pectin and aliphatics compared to untreated seedlings. The results obtained in the present study indicate that the effects of the treatment of different concentration of the aluminium oxide nanoparticles on maize seedlings can be estimated at an early stage, rapidly and cost effectively using spectroscopic techniques.