Fig. 4.

Phenotypes of mca1-null and MCA1ox lines. (A) A seedling of the MCA1ox line S3, showing browning of the hypocotyl. (Scale bars, 2.0 mm.) (B) An MCA1ox plant (line S1), showing a phenotype with no petals, shrunken siliques, short stems, and small rosettes. (White bars, 1.5 mm; black bars, 1.0 cm.) (C) Ca²⁺-dependent growth phenotypes of MCA1ox seedlings (line S1). Note that the ordinary MS medium contains 3.0 mM CaCl₂. On this medium, MCA1ox seedlings exhibited growth deficiency. (Scale bar, 1.0 cm.) (D) Failure to penetrate the lower, harder agar (1.6%) medium of the primary roots of the mca1-null mutant. Seeds of various lines were placed on the surface of the upper, softer agar (0.8%) medium of the two-phase-agar medium, allowed to grow for 9 days, and then photographed. (Left) Wild type (side view). (Upper Center) mca1-null (side view). (Lower Center) mca1-null (oblique upper view), showing the root tips were coiled at the interface of the two agar media. (Right) mca1-null mutant complemented with wild-type MCA1. Arrowheads represent the interface of the two agar media. (Scale bar, 1.0 cm.) (E) Quantitative representation of the results shown in D. Number of seedlings examined: Wild type, n = 150; mca1-null, n = 150; mca1-null + MCA1, n = 80. ∗, P < 0.01 versus wild type and mca1-null + MCA1.