Fig. 2. Chelatable, redox-active Fe accumulation in wheat leaves after Bgt attack. (A) Wheat epidermis 24 hpi with Bgt stained for Fe³⁺ after pretreatment with the Fe³⁺ chelator DFO. (B) In situ calcein staining of Fe³⁺ in wheat leaves 24 hpi with Bgt before (left panel) and after (right panel) treatment with the Fe chelator DFO. (C) Wide-range X-band EPR spectrometry of wheat leaves 24 hpi with (blue solid line) or without (black broken line) Bgt inoculation. Insets are the enlarged high-resolution scanning for high-spin and low-spin Fe³⁺, respectively. The g values of high-spin Fe³⁺ are indicated. Spectral intensities were normalized relative to sample amount. Two independent experiments showed similar results. agt, appressorial germ tube; c, conidium; ha, halo; gc, guard cell; N, epidermal nucleus; pa, papilla. Scale bar, 20 µm.