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The Interaction of Human Serum with the Plant Hormone Indole‐3‐Acetic Acid
Author(s) -
HILDEN JØRGEN,
RøNNIKE FOLKE,
SCHOU HENNING
Publication year - 1976
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1976.tb05030.x
Subject(s) - plant hormone , serum concentration , auxin , plant growth , biology , chemistry , biochemistry , botany , endocrinology , gene
It is well known that human serum inhibits the longitudinal root growth in Lupinus albus L and Triticum sativum Lam. This inhibitory effect has been ascribed to the IAA content in human serum, which unfortunately has never been measured quantitatively. Experiments are presented in which Triticum roots are grown in media with pooled human serum and varying concentrations of IAA. In the presence of 10 −5 M p ‐chlorophenoxy‐isobutyric acid (PCIB) and serum, minute IAA additions promoted the growth. This feature hardly could be expected were the serum inhibition in itself an IAA effect. In view of this finding, renewed but unsuccessful attempts were made to demonstrate a similar promotion in media without serum. To explain the observed response curves, it must be further assumed that serum components bind IAA reversibly. In experiments without PCIB in the medium the response curves were similar at a lower level of growth, except that no growth promotion by IAA was discernible. It is concluded, that the inhibiting effect of human serum on the growth of plant roots is not due to free IAA, although IAA in all probability occurs in that fluid.