Effect of nanosized anatase TiO2 on germination, stress defense enzymes, and fruit nutritional quality of Abelmoschus esculentus (L.) Moench (okra)

• Published in: Arabian journal of geosciences 2020-02, Vol.13 (3), Article 120
• Main Authors: Ogunkunle, Clement Oluseye, Adegboye, Esther Faderera, Okoro, Hussein Kehinde, Vishwakarma, Vinita, Alagarsamy, Karthik, Fatoba, Paul Ojo
• Format: Article
• Language: English
• Subjects: Abelmoschus esculentus; Agricultural land; Anatase; Ascorbic acid; Carbohydrates; Chlorophyll; Earth and Environmental Science; Earth science; Earth Sciences; Ecotoxicology; Enzymes; Food plants; Fruits; Germination; Glutathione; Glutathione reductase; L-Ascorbate peroxidase; Leaves; Malondialdehyde; Nanoparticles; Nutrient deficiency; Nutritive value; Okra; Original Paper; Particle size; Peroxidase; Phytotoxicity; Plants; Quality assurance; Reductases; Roots; Seed germination; Soil; Stress; Superoxide dismutase; Surgical implants; Titanium dioxide; Toxicity
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-020-5121-6

Due to wide-scale generation/use of titanium dioxide (TiO 2 ) nanoparticles, significant release into agricultural soil is inevitable. This has caused great ecotoxicological concern due to their unclear fate in plants, most especially food crops. This study aimed to compare the impact of anatase nano-TiO 2 of two primary diameters ( n TiO 2 [50 nm] and b TiO 2 [68 nm]) on stress enzymes and seed nutritional quality of okra ( Abelmoschus esculentus ) plant. Compared to control, b TiO 2 significantly promoted seed germination in okra while chlorophylls were only enhanced significantly by n TiO 2 and reduced by b TiO 2 . The results of biochemical experiments implied that both nano-TiO 2 particles significantly reduced ascorbate peroxidase (APX) and glutathione reductase (GR) activity levels in roots. Conversely in leaves, APX activity level was significantly reduced by the both nano-TiO 2 particles, while GR activity was promoted. Interestingly, both nano-TiO 2 particles significantly increased superoxide dismutase activity in roots and leaves, indicating that nano-TiO 2 induced toxicity to okra plant. The accumulation of malondialdehyde in leaves was significantly high in okra plants exposed to b TiO 2 , and this underpins the fact that the large-sized nano-TiO 2 portends phytotoxicity to the leaves. In this study, the degree of response of stress enzymes to nano-TiO 2 was particle size. Fruit quality analysis indicated a decrease in Ca, Mg, and Fe contents which was particle size–dependent and dose-dependent. In addition, the proximate compositions (except carbohydrate) of fruits were all negatively altered by both nano-TiO 2 particles. Conclusively, the results suggest that particle size is a factor in the phytotoxicity and the individual effect of both nano-TiO 2 particles on okra plant was dose-dependent.