The effect of nutrients on [¹⁴C] tyrosine incorporation in lettuce (Lactuca sativa L.)

Abstract

Incorporation of [¹⁴C] tyrosine into protein of lettuce seedlings was utilized to determine:

1. the effects of complete nutrient versus CaSO₄ and water alone on the incorporation of labeled amino acid into acid‐precipitable material;

2. The effects of complete nutrient versus CaSO₄ and water alone on the growth of seedlings during the first seven days of inhibition;

3. Whether or not this procedure provides a reliable test of inhibition by a known inhibitor of lettuce seeding growth, p‐coumaric acid.

4. We found that the incorporation of labeled amino acid into acid‐precipitable material is optimum only in the presence of complete nutrient, no matter what the conditions in which the seedlings had been grown, or their age. We also found that the seedlings began to show the results of nutrient deprivation within five days of inhibition. The inhibitor p‐coumaric acid stimulated at the low concentration (0.02 mM) and inhibited at higher concentrations tested (to lmM).

Key words:

• Lettuce
• seedling
• protein
• synthesis
• nutrient
• conditions