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Exposure of barley plants to low P i leads to rapid changes in root respiration that correlate with specific alterations in amino acid substrates
Author(s) -
Alexova Ralitza,
Nelson Clark J.,
Jacoby Richard P.,
Millar A. Harvey
Publication year - 2015
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/nph.13245
Subject(s) - respiration , amino acid , chemistry , biology , biochemistry , botany
Summary The majority of inorganic phosphate (P i ) stress studies in plants have focused on the response after growth has been retarded. Evidence from transcript analysis, however, shows that a P i ‐stress specific response is initiated within minutes of transfer to low P i and in crop plants precedes the expression of P i transporters and depletion of vacuolar P i reserves by days. In order to investigate the physiological and metabolic events during early exposure to low P i in grain crops, we monitored the response of whole barley plants during the first hours following P i withdrawal. Lowering the concentration of P i led to rapid changes in root respiration and leaf gas exchange throughout the early phase of the light course. Combining amino and organic acid analysis with 15 N labelling we show a root‐specific effect on nitrogen metabolism linked to specific substrates of respiration as soon as 1 h following P i withdrawal; this explains the respiratory responses observed and was confirmed by stimulation of respiration by exogenous addition of these respiratory substrates to roots. The rapid adjustment of substrates for respiration in roots during short‐term P i ‐stress is highlighted and this could help guide roots towards P i ‐rich soil patches without compromising biomass accumulation of the plant.