KH2PO4-based PK/UiO-66 nanoparticles for efficient nutrient delivery and plant growth promotion of pea seedlings

Abstract

Current agricultural practices involving foliar fertilization are hampered by significant challenges, including poor nutrient retention on leaf surfaces and consequently low utilization efficiency. To address this, we developed a novel nanoparticle-based foliar delivery system, consisting of P and K-loaded UiO-66 metal–organic framework nanoparticles (PK/UiO-66 NPs). This system was engineered to exhibit superior foliar adhesion and controlled nutrient release. The unique structure and chemical properties of PK/UiO-66 NPs conferred exceptional performance, ensuring a prolonged and steady nutrient supply to plants even after exposure to simulated rainfall. Compared to control groups, pea seedlings treated with PK/UiO-66 NPs demonstrated remarkable growth enhancement, with stem length increasing by up to 24.4% and pod fresh weight surging by 106.6%. The nano-formulation exhibited excellent resistance to rain washout and controlled-release characteristics. PK/UiO-66 NPs released only 62.3% of their P content after 48 hours, in stark contrast to conventional KH₂PO₄ solution, which released over 90% within 2 hours. Furthermore, transcriptomic analysis provided molecular insights into the mechanism of action, revealing that PK/UiO-66 NPs significantly upregulated genes associated with photosynthesis, plant hormone signalling, and overall plant development. This study not only presents a highly effective approach to improve foliar fertilization efficiency, but also establishes a promising platform for the design of advanced, sustainable nano-fertilisers for modern agriculture.