Non-destructive detection of ionic species in plants under Cr(III) stress using LIBS

Aims Plants serve as bioindicators of environmental heavy metal pollution. Rapid, non-destructive techniques for plant elemental analysis are essential for understanding pollutant uptake and nutrient interactions. This study aimed to develop a novel approach integrating Laser-Induced Breakdown Spectroscopy (LIBS) with guttation fluid for non-destructive monitoring of elemental dynamics in Alocasia under Cr (III) stress. Methods Guttation fluid (easy to collect and with a large volume) was collected non-destructively from hydroponically cultivated Alocasia plants subjected to Cr (III) stress. LIBS analysis was performed on fluid samples using a liquid-to-solid enrichment strategy to enhance trace detection. Signal validation was conducted via comparison with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) measurements. Results Guttation fluid elemental composition strongly correlated with plant tissues. Under Cr(III) stress, Cr signal intensity increased with stress concentration, while Mg and Ca signals decreased by approximately 30–40%. The accumulation of Cr in guttation fluid continued to rise to a peak and then decreased (likely associated with root damage). LIBS results showed significant correlation with those obtained by ICP-MS (R 2  = 0.995 for Cr(Ⅰ)). The method achieved a detection limit of 20.3 ppb for Cr with excellent linearity (R 2  = 0.963). Conclusion This LIBS-guttation fluid approach provides a reliable, non-destructive means to monitor plant responses to heavy metal stress, offering potential for environmental biomonitoring and crop safety assessment.