Table 1. Density of Plasmodesmata on Cell Interfaces of C₃ and C₄ Species.

Species	Mean Cell Interface Area (µm2)	Mean Pitfield Area per Cell Interface (µm2)	Mean Pitfield Area per Cell Interface Area (%)	PD per µm2 Pitfield	PD per µm2 Cell Interface	PD Area per Cell Interface Area (%)
M-BS cell interface
Rice, C3	609 ± 25a	17 ± 1a	2.8 ± 0.1a	35.0 ± 0.4a	1.0 ± 0.1a	0.6 ± 0.02a
Wheat, C3	2704 ± 150b	149 ± 28b	5.5 ± 0.3b	46.9 ± 1.0b	2.6 ± 0.1b	2.0 ± 0.03b
S. viridis, C4	486 ± 14c	61 ± 5c	12.7 ± 0.3c	72.8 ± 0.9c	9.3 ± 0.2c	6.2 ± 0.07c
Maize, C4	1203 ± 32d	137 ± 11b	11.4 ± 0.3d	66.1 ± 0.7d	7.5 ± 0.2d	5.4 ± 0.06d
M-M cell interface
Rice, C3	249 ± 9e	10 ± 2d	4.1 ± 0.1e	38.7 ± 0.4e	1.6 ± 0.1e	1.0 ± 0.02e
Wheat, C3	2246 ± 183b	83 ± 16c	3.7 ± 0.2e	41.3 ± 0.7f	1.5 ± 0.1e	1.2 ± 0.02f
S. viridis, C4	375 ± 7f	32 ± 2e	8.5 ± 0.1f	75.2 ± 0.8c	6.4 ± 0.1f	4.2 ± 0.05g
Maize, C4	810 ± 17g	117 ± 6b	14.4 ± 0.2g	77.5 ± 0.6g	11.2 ± 0.2g	8.0 ± 0.07h

Numbers in the “PD per μm² Pitfield” column are the sum of slopes and intercepts shown in Figure 6. Statistical differences according to MATLAB two-sample t test or SPSS Statistics software at P value < 0.05 are indicated by letters. Values indicated by the same letter within a column are not statistically different.