Kortdagplanten

Kortdagplanten, also known as short-day plants, are a category of flowering plants that require a specific period of darkness to initiate flowering. This means they bloom when the nights are longer than the days. The critical factor for these plants is the length of the uninterrupted dark period, not necessarily the total amount of daylight.

The physiological response to photoperiodism, which includes short-day and long-day plants, is mediated by a pigment called phytochrome. Phytochrome exists in two forms, Pr and Pfr, which interconvert depending on light exposure. A prolonged dark period allows for a sufficient reduction in Pfr, signaling the plant to begin the flowering process.

Examples of short-day plants include chrysanthemums, poinsettias, and strawberries. These plants typically flower in the autumn or winter in temperate climates, as these seasons naturally provide the required long nights. Conversely, in tropical regions, where day length is relatively constant, certain short-day plants may flower year-round or require artificial manipulation of light to induce flowering.

Understanding the photoperiodic requirements of short-day plants is crucial for agricultural and horticultural practices. Growers often use artificial lighting to extend the dark period or use shading techniques to ensure optimal flowering and yield for these species. The precise duration of the critical dark period can vary significantly between different short-day plant species.