Table I.

Changes in Glc, Suc, and UDP-Glc content and relative concentration during growth of excised coleoptile sections

Sample	Final Length	Glc	Suc	UDP-Glc
	mm	nmol mg−1 fresh mass		pmol mg−1 fresh mass
Fresh sections	11.0	32.9	5.7	36.7
4.5 h, no sugar	14.7  ± 0.4	23.2	1.9	11.9
9.5 h, no sugar	15.9  ± 0.3	19.9	1.7	7.9
9.5 h, 100 mm Glc	16.4  ± 0.3	40.6	3.9	13.8
9.5 h, 10 mm Gal	14.5  ± 0.3	23.3	1.8	4.7

Sections exactly 11 mm long were sliced with a razor blade 1 to 2 mm below the tip of 3-d-old coleoptiles about 2 to 2.5 cm long. Sections were floated on a medium containing 5 mm potassium phosphate, pH 5.5, 5 mm KCl, 0.01% tetracycline, and 2 × 10⁻⁵ m IAA, and, in some instances, supplemented with 100 mm Glc or 10 mm Gal. The sections were transferred either immediately or after 4.5 or 9.5 h of incubation at 30°C. Matching sets of samples were transferred either immediately or after 3 or 8 h of incubation at 30°C to the same respective media containing radiolabeled Glc and incubated an additional 1.5 h at 30°C. After incubations the sections were rinsed with water and frozen in liquid nitrogen. Length measurements are from 20 coleoptile sections. Values are typical of three independent experiments.