Titanium dioxide nanoparticle (TiO2) mitigation of water-deficit stress in micropropagated sweet potato (Ipomoea batatas) plantlets
摘要
Sweet potato, a vital tropical food crop, is often challenged by abiotic stresses, particularly water-deficit stress. The potential of titanium dioxide (TiO2) nanoparticles to mitigate the adverse effects of water-deficit stress on micropropagated sweet potato plants was investigated. Plants were cultured in Murashige and Skoog basal medium supplemented with varying concentrations of TiO2 nanoparticles (0–150 mg L−1) under water-deficit stress imposed by 0.22 M D-sorbitol (-5.4 MPa). Results demonstrated that water-deficit stress significantly reduced root number. However, the addition of TiO2 nanoparticles at concentrations of 50 and 100 mg L−1 led to a notable increase in root count. Plants treated with 50 mg L−1 TiO2 exhibited an average root count of 3.80 ± 0.41, while those treated with 100 mg L−1 TiO2 had an average root count of 3.10 ± 0.42. TiO2-treated plants exhibited thicker and longer roots, which are advantageous for water absorption. While shoot length was highest in the control, the positive effects of TiO2 nanoparticles on root development were evident. The highest root length was observed in plants treated with 150 mg L−1 TiO2 (21.07 ± 0.91 cm), which was not significantly different from those treated with 100 mg L−1 TiO2 (19.89 ± 0.61 cm). The shortest root length was observed in plants treated with 70 mg L−1 TiO2 (3.13 ± 0.95 cm). The optimal concentration of TiO2 nanoparticles that enhanced the morphological and physiological traits of sweet potato plantlets under water-deficit stress was found to be between 100 and 150 mg L−1. These findings suggest that TiO2 nanoparticles could be a promising strategy for improving sweet potato production in arid and semi-arid regions.