Plant materials and Reagents
The three A. lancea accessions were collected from wild locations (sources and morphological descriptions are listed in Table S1). Chemical standards (>98% purity) including atractylodin, hinesol, β-eudesmol, atractylone, atractylenolide I, atractylenolide II and selina-4(15),7(11)-dien-8-one were purchased from Rongchengxinde (Beijing, China).
Sample preparation for LCM and DESI/PI-MSI.
The fresh AR were trimmed into a cylinder shape (2 cm high) and placed in desired orientation on the plastic embedding rings (Bensheim, Germany). Rings were fixed with the holding clamp of the rotary microtome (Leica RM2265) and 70 μm thin tissue sections were made at -18℃. The slices were mounted on polyethylene terephthalate (PET) microscope slides with steel frames (76 × 26 mm, 1.4 µm; Leica Microsystems, Germany) and stored temporarily at -20℃. For DESI/PI-MSI, the same approach was employed, but plain glass slides (76 × 26 mm, 1.2 mm;Fan chuan, China) were used.