Relationship Between Stomatal Aperture and Herbicide Effectiveness in Eucalyptus viminalis Seedlings

SUMMARY

Stomatal apertures of leaves of Eucalyptus viminalis Labill, seedlings were modified by variations in light intensity, application of the metabolic inhibitor phenyl mercuric acetate, and by drought. Differences in herbicide effectiveness of picloram solutions applied to leaves of differing stomatal aperture were consistent with the hypothesis that stomatal aperture can regulate the amount of herbicide entering the leaf.

However, the results indicated that the conditions which are optimum for one requirement for herbicide action (e.g. uptake) may not be optimum for other requirements (e.g. translocation).