光こう周しゅう性せいこうしゅうせいMeanings1nounphotoperiodism; photoperiodicityBiological term for the response of organisms to the relative lengths of day and night.植しょく物ぶつの開かい花かは光こう周しゅう性せいによって調ちょう節せつされる。Flowering in plants is regulated by photoperiodism.