Fig. 4

Comparative radial anatomy of a radicle, crown root, and large lateral and small lateral root. (A) Radicle transverse section, ∼1.5 cm from the root tip. (B) Crown root transverse section, ∼6 cm from the root tip. (C) Large lateral root transverse section ∼2 cm from the root tip. (D) Small lateral root transverse section. All rice root types display closely related radial anatomies but with variations of the number of mesodermal cell layers. Pictures are not at the same scale. ep, epidermis; ex, exodermis; sc, sclerenchyma; me, mesodermis; ae, aerenchyma; en, endodermis; pe, pericycle. Scale bars, 50 μm. All observations were made under UV illumination. Crown and large lateral roots were collected from 40-day-old plants, while radicles and small lateral roots were collected from 1-week-old seedlings.