Karrikins – effect on plants, interaction with other growth regulators, and potential use in horticulture

Abstract

Karrikins are a group of chemicals found in plant-derived smoke from burning plant material. To date, scientists have concentrated on their effect on seed germination in plants sensitive to smoke. However, there are reports on the effect of karrikins on the physiology and morphology of plants that do not occur in fire areas and are not naturally treated by smoke. These chemicals positively affect the biometric parameters of in vitro cultured plants. Their effect on pollen germination rate in several species has been recently confirmed. They interact with plant growth regulators, enhancing their effects, for example, using them together with auxins, cytokinins, gibberellins, abscisic acid, or ethylene. This paper reviews the present research on karrikins and proposes perspectives for further investigations and applying these chemicals in horticultural production as a new group of plant growth regulators.