Mechanism Of Flower Development And Early Flowering Technique Of Cymbidium Sinense

Cymbidium sinense is a perennial herbaceous plant belonging to the orchidaceae family.It has beautiful leaves and elegant flowers,and is widely used as an ornamental plant.Here,we researched on the mechanism of flowering development of C.sinense by using morphology,histology and physiology methods.On the other hand,we explored the effects of low temperature,photoperiod,GA3,SA on flowering development of C.sinense.Our study will play an important role in providing theoretical basis for the flowering regulation of C.sinense.The main findings are as follows:?1?The flowering development processes mainly contains the flower differentiation and flower growth processes.The flower differentiation processes has six stages,including the undifferentiated stage,flower primordium differentiation stage,flower primordium differentiation stage,sepal differentiation stage,petal primordium differentiation stage and synthetic gynostemium and pollen block differentiation stage.The flower growth processes is divided into six stages,involving the inflorescence differentiation stage,small bell stage,big bell stage,early flowering period,flowering period and late flowering period.?2?We measured the content of soluble sugar,starch,soluble protein,total carbon,and total nitrogen in the pseudobulbs and leaves of C.sinense,as well as the C/N ratio and peroxidase activity.The pseudobulbs and leaves were collected from the plants in different flowering development processes?undifferentiated stage,flower primordium differentiation stage,inflorescence differentiation stage,small bell stage,big bell stage,early flowering period,flowering period and late flowering period?.The results showed that:the content of soluble sugar in pseudobulbs and leaves reached to the maximum value during the early flowering period,and with similar value during the late flowering period and undifferentiated period;the content of starch in pseudobulbs and leaves is very stable during the flowering development processes except the high value in big bell stage;the content of total carbon in pseudobulbs is also displayed relatively stable except the late flowering stage;the content of total nitrogen in pseudobulbs showed a decreasing trend with the development of flowers,and reached to the highest value in the inflorescence differentiation period;the content of soluble protein in pseudobulbs showed the same change trend as in leaves,both of them reached the peak value in the inflorescence differentiation period and early flowering period;peroxidase activity in pseudobulbs displayed an upward trend during the development processes;both of the content of GA3 and IAA in pseudobulbs reached the peak value in inflorescence differentiation period and early flowering period;the content of ABA reached the peak value in early flowering period;the content of ZR reached the peak value in row boll period.?3?The low temperature?day 20 ?,12 h/night 10 ? 12 h?can led to the early flowering period 30.8±3.56 days in advance,and beneficial to prolong the blooming time of single flower and whole inflorescence.But the low temperature resulted in a shorten length of pedicel and the number of florets in a inflorescence reduced to 8.33±3.61.In addition,the low temperature induced lower content of soluble sugar and starch,and higher content of total carbon and total nitrogen in leaves compared with the control group.Besides,we explored the influence of photoperiod,GA3,SA on flowering development of C.sinense by using the orthogonal experimental design method,and the result shows that there are significant differences in their effects on flowering process.Light time wood inhibit the height of C.sinense,and prolonged the blooming time of the whole inflorescence;100 mg-L^-1 GA3 and lower SA both wood shortened the blooming time of the whole inflorescence;50 mg·L^-1 SA wood extended the blooming time of the whole inflorescence.8h lighting + 50 mg·L^-1 GA3 + 25 mg·L^-1 SA led to the number of florets in a inflorescence up to 12.00±2.65.At the same time,high concentration of GA3 significantly improved the content of starch in the early flowering period and the content of soluble protein in flower primordium differentiation stage,50 mg·L^-1 GA3 could significantly increase the C/N ratio in flower primordium differentiation stage;12h lighting and 50 mg·L^-1 SA can significantly increased the content of starch in early flowering period;The concentration of SA has a significant impact on C/N in flower primordium differentiation stage;50 mg·L^-1 SA caused the C/N ratio down to the minimum value in flower primordium differentiation stage.