Flowering induction hypothese 1. Florigen hypothesis(成花素假说) 2 Phytochrome hypothesis(光敏色素假说) 3. Carbon and nitrogen ratio hypothesis(碳氮比 假说)Flowering induction hypotheses 1. Florigen hypothesis （成花素假说） 2. Phytochrome hypothesis （光敏色素假说） 3. Carbon and nitrogen ratio hypothesis (碳氮比 假说）