Fluorine-Tagged 5-Hydroxytryptophan to Investigate Amino Acid Metabolism In Vivo

Table 2

Growth response of tomato seedlings to different low-dose (1 mL) treatments. Low dose of 5-HTP contains ~0.2 𝜇g m𝐿⁻¹ 5-HTP in 1 mL PBS. Low dose of PF-5-HTP contains ~0.3 𝜇g PF-5-HTP per m𝐿⁻¹ PBS (biologically equivalent to 0.12 𝜇g 5-HTP 𝜇g m𝐿⁻¹). Numbers in the table represent the mean values ± standard deviation. Each value is based on 3 replicates with 4 plants each (12 per treatment).

Treatment	Stem length (cm)	Root length (cm)	Leaf biomass (g)	Root biomass (g)
1 mL PBS	5.0 ± 1.7	6.4 ± 2.0	1.3 ± 0.5	5.5 ± 2.0a
1 mL 5-HTP	6.9 ± 1.7	6.6 ± 1.9	1.7 ± 0.4	8.2 ± 1.7b
1 mL PF-5-HTP	4.8 ± 1.7	5.0 ± 1.2	1.1 ± 0.4	6.8 ± 0.8b

PBS:phosphate-buffered saline; 5:HTTP:5-hydroxytryptophan; PF:5-HTTP:5-hydroxytryptophan tagged with multiple-fluorine atoms. Values with the same letters (a, b) were not significantly different at probability level 𝛼< 0.05 as determined by one-way analysis of variance with the Student-Newman-Keuls multiple-comparison test.