Appendix 1—table 1. Parameter values and definitions.

Symbol	Definition	Value	Units	References
Parameters
$N^{C,\text{tot}}$	Solute number in cell (including ions)	$2\times {10}^{-14}$ –$8\times {10}^{-14}$	mol	Estimated from Table 2-3 in Milo and Phillips, 2015
$N^C$	Solute number in cell (excluding ions)	$2\times {10}^{-16}$ –$8\times {10}^{-16}$	mol	Estimated from p. 106 in Milo and Phillips, 2015
$N^N$	Solute number in nucleus (excluding ions)	$2\times {10}^{-17}$ –$6\times {10}^{-17}$	mol	Fit
${\sigma }_{\text{intact}}^C$	Cell wall surface tension	10 –20	N/m	Minc et al., 2009, Atilgan et al., 2015
${\sigma }_{\text{proto}}^C$	Cell membrane surface tension	$4.5\times {10}^{-4}$	N/m	Lemière et al., 2021
${\sigma }^N$	Nuclear membrane surface tension	$4.5\times {10}^{-4}$	N/m	Estimate
${\nu }_{\text{iso}}^C$	Cell non-osmotic volume fraction	0.25		Main Text Figure 2(D)
${\nu }_{\text{iso}}^N$	Nucleus non-osmotic volume fraction	0.25		Main Text Figure 2(E)
$V_{\text{iso, intact}}^C$	Intact cell isotonic volume	88	µm3	Figure 3—figure supplement 1
$V_{\text{iso, intact}}^N$	Intact nucleus isotonic volume	6.7	µm3	Figure 3—figure supplement 1
$V_{\text{iso, proto}}^C$	Protoplast isotonic volume	81	µm3	Figure 3—figure supplement 1
$V_{\text{iso, proto}}^N$	Protoplast nucleus isotonic volume	6.6	µm3	Figure 3—figure supplement 1
$c_{\text{iso, intact}}$	Isotonic sorbitol concentration	0	M (mol/L)	Figure 2—figure supplement 2
$c_{\text{iso, proto}}$	Isotonic sorbitol concentration	0.4	M (mol/L)	Figure 2—figure supplement 2
Variables
$V^C$	Cell volume		µm3
$V^N$	Nuclear volume		µm3
$c^{\text{out}}$	External osmolarity		M (mol/L)