Abstract: Taking ' Hongmian ' cut Chrysanthemum as test material, the black plastic film was used to build shading shed, and six groups of different photoperiod treatments were set up by black film shading method, which were day / night 7 h / 17 h ( recorded as Ph7 ), 8 h / 16 h ( Ph8 ), 9 h / 15 h ( Ph9 ), 10 h / 14 h ( Ph10 ), 11 h / 13 h ( Ph11 ), and long-day ( 13-14 h ) treatment as CK. The effects of different photoperiods on the vegetative growth, flowering and development quality of Chrysanthemum were studied. The time and leaf number of budding, bud breaking, initial flowering and full blooming of different treatments were recorded. The contents of total soluble sugar, sucrose and protein in leaves at different developmental stages were measured and analyzed. The fresh weight of flowers and stems and the distribution rate of dry matter in different organs were measured at the full blooming stage of different treatments. The purpose was to clarify the regulatory effect of different photoperiods on the initial flowering stage and flowering quality of ‘ Hongmian ’ Chrysanthemum, and to propose targeted light supplement suggestions for Chrysanthemum cultivation at different developmental stages. The results showed that,（1）the number of leaves increased with the increase of illumination time, and the increase rate of CK was the largest, followed by Ph11, and Ph7 was the smallest.（2）The flowering time of ' Hongmian ' cut Chrysanthemum was significantly affected by photoperiod. The flowering time of Chrysanthemum under Ph10 treatment was the shortest from seedling stage to budding and flowering. The flowering time of Ph11 from the initial flowering stage to the full blooming stage of petals was the shortest. The flowering time of Ph7, Ph8 and CK was seriously lagging behind.（3）The changes of soluble sugar and protein content in leaves at different developmental stages showed a ' M ' trend, and the two peaks appeared at the flower bud differentiation stage and before flowering. The total soluble sugar content in CK was the highest, followed by Ph11; The contents of soluble protein and sucrose, as the messenger molecules that can perceive photoperiod signals, were the highest in Ph10.（4）Flower fresh weight of Ph11 was the largest, and the effect of flower promotion was significant. Therefore, in order to ensure the quality of cut flowers, the seedling stage should accept more than 11h/d long sunshine conditions, so that the Chrysanthemum seedlings fully vegetative growth and not prematurely induce flower bud differentiation, with 10h/d light conditions for inducing flowers, bud formation and begin to flower color, flower bud differentiation is irreversible, placed in 11h/d light conditions can be the fastest full expansion of petals.

Key words: ‘Hongmian’ Chrysanthemum, Photoperiod, Number of leaves, Flowering period, Soluble sugar, Soluble protein