Study On The Effects Of Different Photoperiod On The Inflorescence Of Camellia Japonica

Camellia japonica with beautiful flowers and green leaves is one of thefamous traditional plants in China, and it has wide market benefits.The paper studied the effects of five kinds of photoperiod(16, 14, 12, 10, 8h light/d) on the two cultivars of camellia japonica( 'White snow tower' and ' White-red peony' ).The morphological and physiological indexes relative to growth were measured. Then the critical daylength and the flower bud differentiation of ' White snow tower ' and ' White-red peony' were defined. The results indicated:(1)Camellia japonica was long-daylength plant, and different cultivar had different critical daylength,the critical daylength of 'White snow tower' was about 14 h light/day,while the critical daylength of 'White-red peony' was about 12 h light/day.It lasted a long time for the flower bud to differentiate, started in early July, ended in early November. The morphodifferentiation of camellia japonica flower bud was suddivided into five parts:initial stage,calyx differentiation stage,petal differentiation stage,gynoecia> stamen differetiation stage and ovary differetiation. Different cultivar underwent different stages, 'White-red peony' went through the five stages all, while 'White snow tower' only had the first three stages.(2)Photoperiod had distinct effects on account of flower, diameter of flower and florescence,long-day length improved the quality of flower. 'White snow tower' under 16h light/d flowered 13d earlier and ended 13d later than that under nature light, 'White snow tower' under 14h light/d flowered 20d later and ended 14d later than CK; 'White-red peony' under 12h light/d flowered 1d earlier and ended 10d later than CK, 'White-red peony' under 14h light/d flowered 1d later and ended 10d later than CK, the blooming date of plants under 16h light/d was the same as CK, but ended 31d later than CK.When the two cultivars treated with long-daylength, the account of flower and their diameter increased.(3)In the experiment, photoperiod had no effects on contents of chlorophylK soluble sugar and soluble protein.The soluble sugar and soluble protein were the substance base of flower bud differentiation. The result indicated that photoperiod was the important factor to flower bud differentiation under appropriate temperature.(4)Photoperiod had effects on endogenous hormone, which was very important for flower bud differentiation.Comparing with leave bud under short-daylength,high contents of GA3 x ZT â– > ABA and low content of IAA were in favor of flower bud differentiation.Based on the theory of balancing of endogenous hormone ,the result showed that: in the period of flower bud physiological differentiation,the increase of ZT/GA3 > ZT/IAA, ABA/IAA> ABA/GA3 and the decrease of ZT/ABA, GA3/IAA benefited the flower bud induction; In the period of flower bud mordifferentiation,low ZT/GA3, ZT/IAA and high GA3/IAA were in favor of flower bud mordifferntiation.