关键词: 桂花, SVP, 环境低温, 花芽分化

Abstract: SVP（SHORT VEGETATIVE PHASE）is a kind of MADS-box transcription factor that regulates plant flowering in response to temperature. It plays an important role in flower bud differentiation. In order to explore the effect of SVP gene in Osmanthus fragrans on flower bud differentiation under different temperature treatments，we observed the anatomical structure of the flower bud differentiation process of Osmanthus fragrans‘Yabhong’under different temperatures （19 ℃ and 25 ℃）. The results showed that compared with 25 ℃，the low temperature of 19 ℃ can significantly promote the flower bud differentiation process of Osmanthus fragrans‘Yabhong’，the most significant effects were inflorescence differentiation and pistil differentiation. qRT-PCR analysis showed that the seven OfSVP genes were expressed in different developmental stages of Osmanthus fragrans‘Yabhong’，and the expression of OfSVP4，OfSVP6，OfSVP7 began to decrease from the inflorescence differentiation stage and reached the lowest level in the pistil differentiation stage.，but the expression level of treatment at 19 ℃ was always lower than 25 ℃ treatment. The expression levels of downstream genes FT，SOC1 and GA20ox2 treated at 19 ℃ were basically higher than 25 ℃ treatment，negatively correlated with OfSVP4，OfSVP6，OfSVP7. Therefore，OfSVP4，OfSVP6，OfSVP7 may be a key gene in response to low temperature-induced flower bud differentiation in Osmanthus fragrans，which may affect the process of flower bud differentiation by regulating the expression of FT，SOC1 and GA20ox2.

Key words: Osmanthus fragrans, SVP, ambient temperature, flower bud differentiation