Table I.

Cytokinin contents^a in maize cultured cells after treatment with various concentrations of cZ^b

CKsc	cZ
	0 nm	1 nm	10 nm	100 nm	1,000 nm
	pmol g−1 fresh wt
tZ	0.64 ± 0.02	0.60 ± 0.01	0.54 ± 0.03	1.18 ± 0.02	5.96 ± 0.04
tZR	2.00 ± 0.04	2.15 ± 0.10	2.05 ± 0.05	2.67 ± 0.05	7.40 ± 0.17
tZRMP	3.20 ± 0.26	3.29 ± 0.38	3.79 ± 0.59	4.87 ± 0.27	27.57 ± 2.14
cZ	0.23 ± 0.03	0.49 ± 0.00	2.66 ± 0.04	26.84 ± 0.99	45.70 ± 0.93
cZR	2.33 ± 0.02	2.80 ± 0.12	6.33 ± 0.24	43.53 ± 1.91	181.32 ± 8.97
cZRMP	4.70 ± 0.31	4.63 ± 0.44	14.84 ± 1.55	119.45 ± 18.65	>QLd

^aMean value from two replicate samples with the average deviation.

^bAfter treatment of maize cultured cells with cZ for 20 min, cells were harvested and washed twice with water. Then, cytokinin content was analyzed as described in “Materials and Methods.”

^cCKs, cytokinins; tZ, trans-zeatin; tZR, tZ riboside; tZRMP, tZR 5′-monophosphate; cZ, cis-zeatin; cZR, cZ riboside; cZRMP, cZR 5′-monophosphate.

^d>QL, content larger than the quantifiable limit (193 pmol g⁻¹ fresh wt).