Young sunflowers track the Sun
Документальне фото поля соняшників у Шумадії, Сербія; одна мить не доводить добового руху чи точного азимута голівок / Documentary sunflower-field photograph in Šumadija, Serbia; a single frame does not establish daily motion or the heads’ exact azimuth. Credit: Petar Milošević; CC BY-SA 3.0. https://creativecommons.org/licenses/by-sa/3.0 Source: https://commons.wikimedia.org/?curid=11096618
Growing young sunflowers turn their shoot tips from east to west during the day and reorient eastward overnight. This heliotropism involves unequal growth on opposite sides of the stem and a circadian clock. Mature flower heads usually stop tracking and remain oriented east. Thus, the familiar claim that all flowering sunflowers follow the Sun throughout the day needs an age qualification.
