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THE PATHWAY OF TRANSPORT OF APPLIED INDOLYL‐ACETIC ACID THROUGH INTERNODE SEGMENTS
Author(s) -
WANGERMANN ELISABETH
Publication year - 1974
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1974.tb01288.x
Subject(s) - pith , phloem , sucrose , botany , vascular bundle , chemistry , apical dominance , biophysics , biology , biochemistry , shoot
S ummaryHelianthus internode segments were fitted with apical donor blocks containing [ 14 C]IAA and [ 3 H]sucrose, and plain agar basal receiver blocks. After transport, donors, tissue and receivers were oxidized in an ‘Oxymat’ and 14 C and 3 H counted separately. Ageing the segments before transport, or pretreatment with TIBA, greatly reduced the amount of 14 C in the receivers, but had no effect on the 3 H count. Profiles of 14 C were determined after transport of [ 14 C]IAA through similar segments ringed to various depths, or with the pith interrupted. Interruption of the vascular bundles, but not of the pith, caused accumulation of I4 C above the cut in segments transporting IAA basipetally; no accumulation was caused by ringing segments transporting IAA acropetally. It is concluded that active polar transport of IAA takes place in or near the phloem, but by a different mechanism from the one involved in sucrose transport through the phloem of intact plants.