The effect of δ‐aminolevulinic acid on red light‐induced unrolling of dark‐grown barley leaf sections

Abstract

Unrolling of sections from dark grown barley leaves (Hordeum vulgare L. cv. Klages) was stimulated by red irradiation. The unrolling started after a lag phase of 6‐8 h and was completed after 24 h. The effect of several keto and amino acids on leaf unrolling was compared with their effect on coleoptile segment expansion growth. Of the substances tested δ‐aminolevulinic acid had the most inhibitive effect on leaf unrolling and the least inhibitive effect on coleoptile segment expansion growth. Prolonged treatment caused a strong inhibition of the unrolling but with a short tretment, a stimulation of the unrolling occurred. The inhibitive effect of δ‐aminolevulinic acid was only found if the treatment started within 6‐8 h after the red irradiation. Kinetin and gibberellic acid could decrease the inhibitory effect of δ‐aminolevulinic acid. A possible role for δ‐aminolevulinic acid working as a triggering substance for leaf unrolling is discussed.