Effects of grandinol and related phloroglucinol derivatives on transpiration and stomatal closure

Grandinol, an inhibitor of seed germination and photosynthesis in Eucalyptus sp., inhibits transpiration and stomatal opening. The acylphloroglucinol structure in grandinol seemed to be essential for these activities. Enhancement of activity was achieved by the introduction of a formyl group into the molecule. Therefore, structural requirements for these activities were very similar to that for the inhibition of seed germination and photosynthesis. Other grandinol-related compounds having two electron-withdrawing groups on the phloroglucinol nuclei were also active in these assays.