Influence of gibberellin A3 and ancymidol on sunflower leaf anatomy

Abstract

The plant growth retardant ancymidol (α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol), when sprayed at 132 mg/L of active ingredient, increased leaf thickness, palisade cell length, and number of cells per unit length, and decreased intercellular space percentage in developing Helianthus annuus L. (sunflower) cv. Mammoth Russian leaves when plants were grown under 400 or 1500 μmol∙s−1∙m−2 photosynthetic photon flux density. Foliar sprays of gibberellic acid at 10–40 mg/L reversed the effects of ancymidol on leaf anatomy. Stomatal density and total stomata per adaxial leaf surface area were increased by ancymidol sprays.