Table 1.

Means from 8–9 readings of the percentage mass of potassium from X-ray microanalysis

Species	Inside involucre	Exposed	Splitting	Desiccated	Dark	4 h of 100 µm ABA
Phaeoceros laevis
Guard cells	2.1 ± 0.18	0.9 ± 0.07	3.8 ± 0.42	1.6 ± 0.12	2.4 ± 0.16	2.4 ± 0.20
Stomatal condition	Closed	Open	Open	Open	Open	Open
Epidermis	1.7 ± 0.12	1.3 ± 0.10	3.9 ± 0.31	1.5 ± 0.09	2.1 ± 0.18	2.0 ± 0.21
Ratio of K in guard cells to that in epidermal cells	1.24	0.69	0.97	1.06	1.14	1.2
Guard cell K relative to epidermis	Higher	Lower	Same	Same	Higher	Same
Thallus control	0.98 ± 0.07
Anthoceros punctatus
Guard cells	1.2 ± 0.06	0.9 ± 0.05	1.3 ± 0.05	1.1 ± 0.06	1.0 ± 0.04	6.0 ± 0.82
Stomatal condition	Closed	Open	Open	Open	Open	Open
Epidermis	1.0 ± 0.02	1.1 ± 0.02	1.3 ± 0.04	1.2 ± 0.04	0.6 ± 0.03	5.8 ± 0.74
Ratio of K in guard cells to that in epidermal cells	1.2	0.82	1.0	0.92	1.67	1.03
Guard cell K relative to epidermis	Higher	Lower	Same	Same	Higher	Same
Arabidopsis*		Turgid		Wilted
Guard cells		3.36 ± 0.36		1.56 ± 0.12
Stomatal condition	Open			Closed
Epidermis		3.24 ± 0.45		3.91 ± 0.64
Ratio of K guard cells to epidermal cells		1.04		0.40
Ratio of K in guard cells to that in epidermal cells		Same		Lower

*From Duckett et al. (2009).