Enhancing agronomic traits of finger millet (Eleusine coracana (L.) gaertn) through seed nano-priming using silicon dioxide nanoparticles (SiO2NPs)

The current study conducted usage of seed nano-priming using silicon dioxide nanoparticles (SiO₂NPs) to assess its impact on the morphological and yield parameters, along with biochemical attributes of Eleusine coracana (L.) Gaertn. Seeds were primed with different concentrations of SiO₂NPs (25, 50, 75, 100, and 125 mg L⁻¹) for 10 h, with respect to the untreated control. The morphological parameters were observed at tillering, ear head, and harvest stages, and at harvest stage in control plants the shoot length was 81.1 ± 1.4 cm with 12.5 ± 0.4 number of leaves. Nano-priming increased these parameters, and maximum shoot length (99.5 ± 1.1 cm) and number of leaves (14.8 ± 0.5) were recorded for plant nano-primed with 100 mg L⁻¹ SiO₂NPs. Similarly, yield parameters like number of fingers/spike (8.2 ± 0.4), length of fingers (spikelets)/spike (15.5 ± 0.7 cm), grain yield/plant (8.5 ± 0.2 g), and straw weight/plant (15 ± 0.3 g) were also significantly higher in plant nano-primed with 100 mg L⁻¹ SiO₂NPs in comparison to control plant. Estimating the pigment contents suggested that the contents were higher in reproductive stage than vegetative stage plants for both control and nano-primed plants. The chlorophyll a (360.48 ± 4.59 μg g⁻¹ FW), chlorophyll b (277.60 ± 3.32 μg g⁻¹ FW), total chlorophyll (638.08 ± 2.83 μg g⁻¹ FW), and carotenoid (184.31 ± 2.78 μg g⁻¹ FW) contents were lowest in control plant. Their amounts were significantly increased after nano-priming with 100 mg L⁻¹ SiO₂NPs except chlorophyll b which was higher at 125 mg L⁻¹ SiO₂NPs, and it was as follows: chlorophyll a (535.05 ± 8.29 μg g⁻¹ FW), chlorophyll b (376.31 ± 5.70 μg g⁻¹ FW), total chlorophyll (897.55 ± 1.51 μg g⁻¹ FW), and carotenoid (279.47 ± 2.75 μg g⁻¹ FW). Similar trend was recorded for antioxidant enzyme activities where the activities of superoxide dismutase (SOD, 23.92 ± 0.60 U g⁻¹ FW), catalase (CAT, 47.91 ± 1.56 U g⁻¹ FW), and guaiacol peroxidase (GPX, 5.49 ± 0.03 U g⁻¹ FW) were highest in reproductive stage plant primed with 100 mg L⁻¹ SiO₂NPs. Present study confirmed the role of SiO₂NPs on growth and biochemical responses in E. coracana, and also the better growth of plants can be correlated with the increased pigment contents and activities of antioxidant enzymes. This study suggests the use of SiO₂NPs as growth enhancer at moderate concentration, and it can be considered an effective strategy for enhancing the production of this crop and emphasizing the need for its careful usage for agricultural purposes.