Silica Nanomaterials Promote Rice Tillering and Yield by Regulating Rhizosphere Processes, Nitrogen Uptake, and Hormone Pathways
Le Yue, Jing Wang, Xuesong Cao, Chuanxi Wang, Chuanxin Ma, Feiran Chen, Bingxu Cheng, Feng Yan, Zhenyu Wang, Baoshan Xing
Abstract
Nanotechnology has attracted worldwide attention as an effective method for sustainable crop production. Herein, silica nanomaterials (SiO 2 NMs) with different sizes and concentrations were applied in paddy soils to explore their effects on rice seedlings. SiO 2 NMs of 8 nm size at 50 mg·kg –1 exhibited the best performance to increase rice growth as compared with the control and conventional Si fertilizer (sodium silicate, Na 2 SiO 3 ). SiO 2 NMs could be a slow-release Si fertilizer to enhance the availability of monosilicic acid in rhizosphere. More interestingly, SiO 2 NMs significantly enhanced the rice tiller number by 100% over the control, while Na 2 SiO 3 showed little effects. The promotion mechanisms of rice tillering by SiO 2 NMs are as follows: SiO 2 NMs enhanced the N content by 109.8 and 21.2% in shoots and roots, respectively, by optimizing root exudates and rhizosphere soil bacterial community; SiO 2 NMs increased the content ratio of cytokinin/auxin by 140.8% and decreased the content of GA 1 and GA 4 (GA = gibberellic acid) by 38.4 and 58.3%; and SiO 2 NMs up-regulated the tillering-related gene expressions (e.g., OsMOC, OsFON, and OsTB ) by 50.6–282.8%. In addition, the SiO 2 NM treatment significantly elevated the rice grain yield after the whole growth period. The findings highlight the promising potential of SiO 2 NMs for sustainable crop production.