Abstract: In order to explore the flowering effect of different photoperiods and its relationship with hormones and growth,Hongmian autumn chrysanthemum was used as test material,and five photoperiod treatments were set up.The natural photoperiod(long-day photoperiods) in summer in Nanjing was used as control.Photosynthetic pigments(chlorophyll a,chlorophyll b,carotenoids),growth indexes(plant height,stem diameter,leaf number),root activity,development duration of different periods and endogenous hormones(budding stage,bud breaking stage,petal formation stage,initial flowering stage,full blooming stage,early wilting stage),flower quality(flower diameter,flower number per plant,anthocyanin) were measured.The results showed that the chrysanthemum grew most vigorously under long-day photoperiods,the plant was tall and strong,and the photosynthetic pigment content was high.7 h/17 h,8 h/16 h plant photosynthetic pigment content was low,the worst growth,lodging,due to light stress,root activity was higher.The growth of plants under 10 h/14 h was dwarfing symmetrical and they had small plant height,thick stem and dense leaves.The flowering response of chrysanthemum was closely related to the endogenous hormone content in leaves.The flower development rate of chrysanthemum was inversely proportional to IAA and GA₃,and was proportional to ZT and ABA.7 h/17 h,8 h/16 h and long-day photoperiods significantly delayed the flowering stage of chrysanthemum.In long-day photoperiods,due to sufficient growth,the cut flowers were large and more but wilted quickly.In 7 h/17 h and 8 h/16 h,due to insufficient vegetative growth,chrysanthemum was small and less,the anthocyanin content was low,and the flower quality was the worst.Flower bud differentiation started fastest at 10 h/14 h,and the development cycle of inflorescence was short,the flowering was early and lasted for a long time.The quality of flowers was also high due to good growth conditions.Photoperiod had the greatest influence on the initiation of flower bud differentiation and the formation of buds.Although the expansion of hyoid petals was also affected by photoperiod,it did not play a decisive role in the advance of flowering.Thus,under the control of 10 h/14 h chrysanthemum in growth morphology,inflorescence development cycle,cut flower quality performance was the best,most suitable for summer in Nanjing Area chrysanthemum flower cultivation,when chrysanthemum bud color after moving to long sunshine normal flowering.

Key words: Chrysanthemum, Photoperiod, Growth index, Endogenous hormone, Development process, Flower quality

CLC Number: 

• S682.01