Real-Time In Situ\nTracking of the Penetration and\nUptake Behavior of Nano-pesticides in Tea Plants Using Surface-Enhanced\nRaman Spectroscopy

In situ monitoring of the uptake\nand transportation process\nof\nnano-pesticides during crop growth remains challenging thus far. In\nthis report, the different three sizes of surface-enhanced Raman spectroscopy\nprobes of nano-pesticides loaded with ferbam and acetamiprid are representative\nnon-systemic or systemic pesticides, respectively. The probes were\nverified to have strong signals of the Raman spectrum enhancement\neffect. They were further applied on the leaves and roots of tea plants.\nWithin 5 h, the nano-pesticides of 50 nm and 100 nm except 150 nm\nprobes could rapidly penetrate young tea leaves to a depth of about\n150–290 μm. Whereas none of the probes were observed\nto penetrate mature leaves and roots of tea plants. The result showed\nthat the penetration rate depended on the size of the nano-pesticides\nand the structure or maturity of the plant tissue rather than the\nloaded pesticides. The penetration rate of small-sized nano-pesticides\nin young tea leaves is the fastest.