Table II. Compartmental ion and sugar concentrations of guard cells of closed and open stomata (in mm).
Data relate to V. faba unless noted otherwise. References are as follows: Fischer (1968); Allaway (1973); Raschke et al. (1975); Raschke and Schnabl (1978); Van Kirk and Raschke (1978a, 1978b); MacRobbie (1983b); Clint and Blatt (1989); Talbott and Zeiger (1993, 1996); Thiel et al. (1993); Marschner (1995); Willmer and Fricker (1996); Guo et al. (2003); Dodd et al. (2005, 2007).
| Solute | Apoplast |
Cytosol |
Vacuole |
|||
|---|---|---|---|---|---|---|
| Closed | Open | Closed | Open | Closed | Open | |
| K+ | 0.05–114 | 0.05–24 | 55–93 | 150–247 | 38–92 | 181–454 |
| H+ (pH)a,b | 6.2–7.1 | 4.8–6.5 | 7.4–7.9 | 7.2–7.7 | 5.2–6.5 | 4.0–5.3 |
| Ca2+c | 0.05–1.0 | 0.5–1.7 | 0.1–0.9 µm | 0.09–0.45 µm | 1–5 | 3–22 |
| Cl−d | 0.3–44 | 0.1–7 | 3–20 | 11–50 | 3–40 | 40–124 |
| NO3−a,b | 0.1–0.2 | 1–0.2 | 2–5 | 2–5 | 10–92 | 10–92 |
| PO42−a | 0.3–0.7 | 3–0.7 | 2–6 | 2–6 | 4–92 | 4–92 |
| Mald | 0.5–20 | 0.4–3.5 | 0.1–6 | 2–25 | 5–48 | 41–464 |
| Suc | 0.4–3 | 1–8 | 12–20 | 6–75 | 1–27 | 45–200 |
a
Values are typical for glycophytic plants.
b
Values incorporate data from Commelina communis and Arabidopsis guard cells.
c
Cytosol values are free concentrations.
d
Cl− will exchange with Mal, subject to availability.