Effects of different plant hormones on flower induction of Rhododendron pulchrum Determination of the Critical Period of Floral Induction for Hybrid Plants Between Lilium × formolongi and Oriental Hybrid Lily Determination of the Critical Period of Floral Induction for Hybrid Plants Between Lilium × formolongi and Oriental Hybrid Lily Flower induction and physiological response of Citrus reticulata "Shatangju" to low temperature under solar greenhouse condition