Reversal of glyphosate inhibition of Sandersonia aurantiaca flower senescence with aromatic amino acids
Jocelyn R. Eason, Jason W. Johnston and Leigh de Vre
Postharvest Biology and Technology Vol: 18 Issue: 1 Pages: 81-84.
2000
บทคัดย่อ
Glyphosate (N-(phosphonomethyl) glycine) is a broad spectrum post-emergence herbicide. This herbicide inhibits the shikimate pathway enzyme EPSP synthase (5-enol pyruvylshikimate 3-phosphate synthase), thereby interfering with aromatic amino acid metabolism. During preliminary investigations with inhibitors of protein and amino acid biosynthesis, we noticed that vase solutions containing glyphosate altered the normal pattern of Sandersonia aurantiaca flower senescence. Further studies showed that although glyphosate (2 mM) was toxic to all green tissue on the flower stem, the senescence of mature flowers (no green tissue) was delayed. Glyphosate-treated flowers did not fade but stayed a bright orange colour and the compressive strength of the flowers was greater (the flowers were less wilted) than the control flowers that were held in water. Treatment of flowers with vase solutions of phenylalanine (2 mM) and tyrosine (2 mM) in the presence of glyphosate reversed the beneficial effect that glyphosate treatment had on flower senescence. The data indicate that a lack of aromatic amino acids may be the cause of delayed fading and wilting of glyphosate-treated sandersonia flowers.