Synthesis of L-ascorbic acid in the phloem

BMC Plant Biology

Table 3 Conversion of ¹⁴C-precursors to AsA in celery tissues

Substrate Tissue	d-[U-¹⁴C]glucose		d-[U-¹⁴C]mannose		l-[1-¹⁴C]galactose
	Parenchyma	Vascular	Parenchyma	Vascular	Parenchyma	Vascular
% Incorporation to AsA^a	1.4 ± 0.06	3.1 ± 0.23	2.7 ± 0.06	5.9 ± 0.23	19.9 ± 0.92	49.8 ± 0.46
Uptake (μCi gFW^-1)^a	0.65 ± 0.07	3.61 ± 0.05	0.32 ± 0.02	3.49 ± 0.05	0.09 ± 0.01	0.67 ± 0.02
Uptake (nmol gFW^-1)^a	2.1 ± 0.23	11.6 ± 0.17	1.0 ± 0.06	11.4 ± 0.17	1.6 ± 0.12	12.2 ± 0.23

^a Values are presented as mean ± S.E., n = 3. Samples were prepared and incubated as described in the text. After incubation samples were extracted with 5% (w/v) PCA containing 5 mM TCEP and AsA purified as described in materials and methods. Radiolabel distribution to AsA was quantified by HPLC using online flow scintillation detection.

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