jour long

CONT: La durée du jour commande le rythme sexuel de beaucoup d'êtres vivants : certaines plantes ne fleurissent qu'en jours courts, d'autres seulement en jours longs selon leur sensibilité à la photopériode.

CONT: Some plants are long day, requiring 14 - 16 hours of sunlight per day to flower. Others are short day requiring only 8 - 9 hours. Others are day neutral and unaffected by day length. Photoperiosim also effects the breeding cycles of farm livestock.
OBS: Long-day plants flower only when exposed to day lengths longer than their critical length. These are usually late spring and early summer flowers.