Table III.

Ca²⁺ in the external solution (4.0 cm³ of 70 mm KCl) after a 5-min incubation in the light (PPFD 350 μmol m⁻² s⁻¹) at the appropriate temperature of freshly-peeled epidermal strips (approximately 1.0 by 1.5 cm², exact size noted) from intact C. communis and tobacco plants kept at RT under lights

Species	Temperature	Apoplast CaCl2 Concentration cm2/cm3	Increase from C. communis to Tobacco
	°C	m
C. communis	27	2.2 ± 0.8	–
		×10−5
C. communis	7	2.0 ± 0.5	–
		×10−5
Tobacco	27	3.0 ± 1.0	13.6-Fold
		×10−4
Tobacco	7	2.4 ± 0.7	12.0-Fold
		×10−4

Ca²⁺ concentration remaining in the solution as measured with a calcium electrode was expressed on a per cm² epidermis per cm³ medium basis (n = 6).