Figure 4.

Delivery and sampling of biomolecules in xylem. a) Delivery of luciferin into the petiole xylem; by providing external luciferase, ATP, and Mg²⁺, the whole leaf emits light (exposure time 30 s, image adjusted for display purpose). b) Two arrays of phytoinjectors loaded with different payloads (luciferin for blue injectors and luciferase for red ones, blue and red here are only for display purpose) targeting petiole's xylem concurrently. By providing external ATP and Mg²⁺, the leaf vein emits light (exposure time 120 s, image adjusted for display purpose). c) Sampling of luciferin and Mg²⁺ delivered to petiole xylem by Cs₂₀SF₈₀ phytoinjectors using an SF phytosampler (exposure time 30 s for dark field). d) Swelling of and water movement in a phytosampler injected into agar gel indicating the possible use to sample plant fluids. e) Corresponding water penetration length with time. f) A phytosampler injected into toluidine blue agar gel becomes blue in 1 min. Data are mean ± s.d (n = 3).