The remaining seedlings were used for the measurement of root anatomy. Fresh
cross-sections in apical and basal root regions (with similar diameter about
0.8e1 mm, and 8e9 cm in length), were cut by hand with a sharp razor. The
transverse sections were then stained with Phloroglucinol and concentrated
hydrochloric acid to detect lignification (Armstrong and Armstrong, 2001, 2005).
Finally, specimens were examined and photographed using an Olympus BX40
photomicroscope.