Fig. 2: OSCA2.1 and OSCA2.2 are required for water-initiated and Ca²⁺-dependent pollen germination in Arabidopsis.

a,b, Pollen germination rates in Arabidopsis single OSCA T-DNA mutants (a) and double or triple mutants (b). n = 3–5 independent experiments. In box plots, the centre line is the median, box edges delineate first and third quartiles and whiskers extend to minimum and maximum values. WT, wild type. c, Pollen germination rates in OSCA2.1 and OSCA2.2 single and double mutants placed side-by-side on the standard germination medium (535 mOsm) for 6 h, as in Extended Data Fig. 3c. Data are mean ± s.d.; n = 3–5 independent experiments. d,e, Micrographs of pollen grains from wild-type and osca2.1/2.2 plants placed on wild-type stigmas and stained with aniline blue. Pollen grains were stained 2 h after pollination (d) and germination rates were counted (e). Data are mean ± s.d.; WT, n = 27 stigmas; osca2.1/2.2, n = 39 stigmas. Scale bars, 50 μm. f–h, Defects of hypo-osmolarity-dependent and Ca²⁺-dependent germination in osca2.1/2.2 pollen. Pollen grains were placed on agarose medium with high or low osmolarity (relative to 535 mOsm) and high or low Ca²⁺ concentration (relative to 2 mM) for 6 h, and were viewed under the microscope (f). f, Germination rates are indicated as a percentage above each image. Scale bars, 50 μm. g,h, Germination rates with 5 mM CaCl₂ and varying osmolarity (g) or low osmolarity (420 mOsm) and varying CaCl₂ concentration (h) in agarose media from experiments similar to f. Data are mean ± s.d.; n = 3 independent experiments for each data point; two-way analysis of variance (ANOVA), P < 0.001.

Source Data