Uptake of amino acids and peptides by developing barley embryos

Tuomas Sopanen (Corresponding Author), Tuija Sinervo, Hannu Ahokas

Research output: Contribution to journalArticleScientificpeer-review

6 Citations (Scopus)

Abstract

Developing embryos of barley (Hordeum vulgare L. cv. Bomi) detached 21–27 days after anthesis took up 1 mM [14C]‐glutamine at pH 5 and 30°C at a rate of about 20 nmol embryo−l h−1 (5 μol g−1h−1). The uptake was inhibited by about 50% by di‐nitrophenol and by about 80% by 300 mM unlabelled glutamine or alanine. The bulk of the uptake appeared, therefore, to be due to carrier‐mediated active transport. The pH optimum of the uptake was 4.5. Leucine, proline, lysine, arginine and as‐paragine were taken up at approximately similar rates as glutamine, and they also inhibited the uptake of glutamine. This, suggests that the uptake of glutamine was at least partly due to an unspecific carrier(s) also shared by other amino acids. The embryos also took up the dipepti.de glycykarcosine; the rate was about 6 nmol embryo−1h−1 (1.5 μol g−1h−1) (2 mM glycylsarcosine, pH 4.5, 30°C). The uptake was inhibited by about 70% by dinitrophenol or by 300 mM glycylglycine. This indicates that the bulk of the uptake was due to carrier‐mediated active transport. The pH optimum of the uptake was about 4.5.

The rates of glutamine and glycylsarcosine uptake increased during the early and middle stages of embryo development (until day 28 after anthesis), but decreased towards the end of the maturation of the grain. These changes, as well as the relatively high activities, suggest that carrier‐mediated active uptake of amino acids, and possibly also that of peptides, plays a role in the nutrition of the developing embryo.

Original languageEnglish
Article number16A
Pages (from-to)347-351
Number of pages5
JournalPhysiologia Plantarum
Volume65
Issue number4
DOIs
Publication statusPublished - 1985
MoE publication typeNot Eligible

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