A Diurnal Component to the Variation in Sieve Tube Amino Acid Content in Wheat
- 16 April 2008
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 147 (2), 912-921
- https://doi.org/10.1104/pp.108.116079
Abstract
We have used high-sensitivity capillary electrophoresis coupled to a laser-induced fluorescence detection method to quantify 16 amino acids in wheat (Triticum aestivum) sieve tube (ST) samples as small as 2 nL collected by severing the stylets of feeding aphids. The sensitivity of the method was sufficient to determine a quantitative amino acid profile of individual STs without the need to bulk samples to produce larger volumes for analysis. This allowed the observation of the full range of variation that exists in individual STs. Some of the total concentrations of amino acids recorded are higher than those reported previously. The results obtained show variation in the concentrations of phenylalanine (Phe), histidine/valine (His/Val), leucine/isoleucine (Leu/Ile), arginine, asparagine, glutamine, tyrosine (Tyr), and lysine (Lys) across the ST samples. These could not be explained by plant-to-plant variation. Statistical analyses revealed five analytes (Tyr, Lys, Phe, His/Val, and Leu/Ile) that showed striking covariation in their concentrations across ST samples. A regression analysis revealed a significant relationship between the concentrations of Tyr, Lys, Phe, Leu/Ile, His/Val, asparagine, arginine, and proline and the time of collection of ST samples, with these amino acids increasing in concentration during the afternoon. This increase was confirmed to occur in individual STs by analyzing samples obtained from stylet bundles exuding for many hours. Finally, an apparent relationship between the exudation rate of ST sap and its total amino acid concentration was observed: samples containing higher total amino acid concentrations were observed to exude from the severed stylet bundles more slowly.Keywords
This publication has 22 references indexed in Scilit:
- Profiling of amine metabolites in human biofluids by micellar electrokinetic chromatography with laser-induced fluorescence detectionAnalytical and Bioanalytical Chemistry, 2007
- Amino acid analysis by micellar electrokinetic chromatography with laser‐induced fluorescence detection: Application to nanolitre‐volume biological samples from Arabidopsis thaliana and Myzus persicaeElectrophoresis, 2005
- High Affinity Amino Acid Transporters Specifically Expressed in Xylem Parenchyma and Developing Seeds of ArabidopsisJournal of Biological Chemistry, 2002
- Interaction between sieve element and companion cell and the consequences for photoassimilate distribution. Two structural hardware frames with associated physiological software packages in dicotyledons?Journal of Experimental Botany, 1996
- Phloem Transport of Amino Acids in Relation to their Cytosolic Levels in Barley LeavesPlant Physiology, 1992
- Amino Acid and Sucrose Content Determined in the Cytosolic, Chloroplastic, and Vacuolar Compartments and in the Phloem Sap of Spinach LeavesPlant Physiology, 1991
- A guide to the use of the exuding-stylet technique in phloem physiologyPlanta, 1984
- Translocation from leaves to fruits of a legume, studied by a phloem bleeding technique: Diurnal changes and effects of continuous darknessPlanta, 1976
- Enhancement of Phloem Exudation from Cut Petioles by Chelating AgentsPlant Physiology, 1974
- SIZE OF PORES AND THEIR CONTENTS IN SIEVE ELEMENTS OF DICOTYLEDONSProceedings of the National Academy of Sciences of the United States of America, 1959