anthesis

Anthesis is the period during which a flower is fully open and functional, enabling reproduction. It denotes the onset of the flower’s reproductive phase and may involve pollen release from the anthers, stigma receptivity, or both, depending on the species. In many flowering plants, anthesis is restricted to a short window of time, sometimes a few hours, and its timing can be strongly influenced by temperature, light, humidity, and plant age. Some species exhibit nocturnal anthesis, opening flowers in the evening or night to match their pollinators.

Anthesis is often associated with specific daily rhythms and can be staggered within a plant or among populations. Floral strategies such as protandry (pollen release before stigma becomes receptive) and protogyny (stigma receptive before pollen release) promote cross-pollination and reduce self-fertilization. Dichogamy refers to the temporal separation of male and female function within a flower or plant.

In agricultural and horticultural contexts, anthesis is a key phenological marker. The date of anthesis can influence pollination success, fruit set, and yield, and is used in breeding, crop management, and climate impact studies. In cereals, for example, anthesis describes the stage when anthers emerge and shed pollen, while in many fruit crops it marks peak nectar and pollen availability for pollinators.

Ecologically, anthesis interacts with pollinator behavior and plant–pollinator coevolution. Nectar production, scent, and flower morphology are often synchronized with the anthesis period to maximize visitation.