Figure 2.

Primary root defects of drh2. A, Seven-day-old wild-type and mutant seedlings. The primary root length of the mutant is about 4-fold less than that of the wild type (arrowheads). The shorter primary root of drh2 was due to a reduced growth zone, as indicated by the emergence of root hairs closer to the root tip compared with the wild type (white vertical bars in the inset). B, In 11-d-old seedlings, differences in root architecture between the wild type and mutant become more apparent. In addition to the short primary root, drh2 seedlings had about two adventitious roots (arrowheads in the inset) while wild-type seedlings had none. C, At 16 d, drh2 primary roots started to elongate faster compared with the earlier stages of seedling development but were still significantly shorter than in the wild type. Bars = 200 μm for insets in A and B.