Table 2. Glu/Gln ratio in fronds of the As-hyperaccumulator ferns P. cretica var. Albo-lineata (Pc-A) and P. cretica var. Parkerii (Pc-P) and the As-non-hyperaccumulator fern P. straminea (Ps) after 23 weeks of exposure to As.

		Ferns
Variants		Pc-A	Pc-P	Ps
Control	$\overline{\mathrm{x}}$ ± SE	0.679±0.068	1.340±0.237	5.580±1.620
	%*	100	100	100
As1	$\overline{\mathrm{x}}$ ± SE	0.278±0.031	0.501±0.104	1.60±0.291
	%*	41.0	37.4	28.6
As2	$\overline{\mathrm{x}}$ ± SE	0.243±0.032	0.148±0.023	0.331±0.031
	%*	35.9	11.1	5.9

Values are mean ± standard error (SE).

* Glu/Gln ratio, where control corresponds to 100%.