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MODULATION, BY PHENOLIC COMPOUNDS, OF ENDOGENOUS MANGANESE DURING IAA‐INDUCED GROWTH IN AVENA COLEOPTILE SEGMENTS: AN ELECTRON SPIN RESONANCE STUDY
Author(s) -
KRISHNA T. MOHAN,
BHARTI SUDHAKAR
Publication year - 1983
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.1469-8137.1983.tb02703.x
Subject(s) - coleoptile , endogeny , avena , electron paramagnetic resonance , manganese , chemistry , caffeic acid , biochemistry , antioxidant , biology , nuclear magnetic resonance , botany , organic chemistry , physics
S ummary The behaviour of endogenous manganese (Mn 2+ ) was studied by electron spin resonance spectroscopy during growth induced by indol‐3‐ylacetic acid (IAA) and modulated by phenolic acids in Avena coleoptile segments. Oat coleoptile segments show a characteristic sextet hyperfine spectrum which is similar in appearance to the sextet of Mn 2+ In aqueous solution. Endogenous Mn 2+ shows a concentration response to IAA, Coleoptile segments treated with p ‐hydroxy benzoic acid and 2,4‐dicblorophenol, which inhibit IAA‐induced growth, show a decline in the concentration of endogenous Mn 2+ . Chlorogenic acid and caffeic acid, which synergize IAA‐induced growth, keep endogenous manganese in the reduced state (i.e. Mn 2+ ) probably by donating electrons in the reaction. It appears that conditions inhibitory to IAA‐induced growth are associated with a decreased level of tissue Mn 2+ while those stimulatory to growth seem to be associated with a higher level of endogenous Mn 2+ . The changes in endogenous Mn 2+ may be mediated either by complex formation or by a change in the redox state.