Fig. 2: Quantification of endosperm pressure and of seed growth pattern in iku2.
From: Evidence that endosperm turgor pressure both promotes and restricts seed growth and size
a Expression of pIKU2::VENUS-N7 in the endosperm of seeds at 1 day post-anthesis (z-sum projection of a confocal stack), scale bar: 10 µm (n = 15 seeds from 2 insertions). b Representative Col-0 and iku2 seeds at 10 DPA. Scale bars: 100 µm. c WT and iku2 seed growth patterns (Col-0, 6 independent experiments: 0DPA: n = 428, 1DPA: n = 485, 2DPA: n = 529, 3 DPA: n = 483, 4 DPA: n = 510, 5 DPA: n = 511, 6 DPA: n = 505, 7 DPA: n = 493, 8 DPA n = 501, 9 DPA: n = 446, 10 DPA: n = 447; iku2, 4 independent experiments: 0DPA: n = 275, 1DPA: n = 280, 2DPA: n = 355, 3 DPA: n = 324, 4 DPA: n = 360, 5 DPA: n = 369, 6 DPA: n = 353, 7 DPA: n = 322, 8 DPA n = 304, 9 DPA: n = 237, 10 DPA: n = 336). The black bars show the SD. Areas were compared using two-sided Student tests without adjustments for multiple comparisons, **p < 0.01, **p < 0.001, ****p < 0.0001. d Extraction of Col-0 and iku2 endosperm pressure through stiffness measurements performed by nanoindentation (Col-0: preglobular: n = 15, globular: n = 23, triangular/heart: n = 14, torpedo: n = 51; iku2: preglobular: n = 16, globular: n = 51, triangular/heart: n = 37, torpedo: n = 22). The centerline shows the median; the box limits show the upper and lower quartiles, the whiskers correspond to 1.5× interquartile range. Individual points are superimposed in black. Pressure values were compared using two-sided Student tests without adjustments for multiple comparisons, **p < 0.01, ***p < 0.001. e Time-dependent pressure functions used as inputs in simulations. Two pressure functions were directly fitted from experimental measurements (pool of 4 independent experiments, labeled iku2 and Col-0 pressure drops, Col-0: preglobular: n = 31, globular: n = 109, triangular/heart: n = 84, torpedo: n = 100; iku2: preglobular: n = 51, globular: n = 89, triangular/heart: n = 76, torpedo: n = 106); three others were interpolated as linear combinations of these two functions (resp. 75–25%, 50–50% and 25–75%). f Relative seed radius as a function of time using the pressure drop functions displayed in e as input. All simulations were performed over the 100-parameter value sets best-fitting iku2 experimental data extracted using the iku2 pressure drop function presented in e as an input (Col-0, 6 independent experiments: 0DPA: n = 428, 1DPA: n = 485, 2DPA: n = 529, 3 DPA: n = 483, 4 DPA: n = 510, 5 DPA: n = 511, 6 DPA: n = 505, 7 DPA: n = 493, 8 DPA n = 501, 9 DPA: n = 446, 10 DPA: n = 447; iku2, 4 independent experiments: 0DPA: n = 275, 1DPA: n = 280, 2DPA: n = 355, 3 DPA: n = 324, 4 DPA: n = 360, 5 DPA: n = 369, 6 DPA: n = 353, 7 DPA: n = 322, 8 DPA n = 304, 9 DPA: n = 237, 10 DPA: n = 336). Plain curves display the mean dynamics and confidence intervals show standard deviations. In both panels, markers depict averaged experimental measurements and error bars standard deviations.
