Unveiling the Real-Time plant growth dynamics using wearable fiber Bragg grating sensors with enhanced Resilience for Agricultural Intelligence

Abstract

Accurate and continuous monitoring of plant growth under drought stress is essential for understanding plant growth responses during dynamic irrigation regimes. However, conventional measurement techniques are often invasive, labor-intensive, or lack the resolution and temporal continuity required for detecting subtle growth changes under variable water conditions. Therefore, this study introduces a highly sensitive, non-invasive wearable Fiber Bragg Grating (FBG) sensor system for real-time monitoring of eggplant fruit expansion. These wearable FBG sensors were embedded with flexible silicone strips and demonstrated a measurement range upto to 25.40 mm, a high resolution of 2.75 × 10^-4 mm, and a sensitivity of 3.36 nm/mm. Designed for field adaptability, the sensors could operate continuously for 7 to 15 days without recalibration or performance degradation. A comparative analysis of eggplant growth under irrigated and drought conditions revealed significant reductions in circumferential expansion, reflecting the growth-impeding consequences of water-deficit signaling pathways. The sensors were tested under two irrigation and two drought phases and exhibited excellent agreement with the standard cylindrical ring tower method (R² = 0.9989). Under normal irrigation, fruits expanded by 24.64 mm and 25.40 mm, while drought conditions reduced growth to 10.15 mm and 11.78 mm, confirming significant inhibition of fruit expansion. Additionally, diurnal growth patterns were observed, with midday shrinkage and nocturnal expansion, reflecting a linear trend influenced by water availability. These results demonstrate the capability of our wearable FBG sensors to detect subtle growth variations and drought-induced changes, offering a reliable tool for studying plant water stress responses and enhancing precision irrigation strategies.