The Growth, Development And Flowering Control Of Primula Maximowiczii

Primula maximowiczii is one of the perennial species in genus Primula, widespread in northern China, with great potential to be used as garden plant and pot flower. In this paper, to shorten the period of vegetative growth, make the plants survival in summer, regulate and control flowering time of P. maximowiczii, the effects of photoperiod, temperature and exogenous gibberellin on bud germination, growth and development of P. maximowiczii were studied. At the same time, the effects of cold storage on flowering quality of three kinds of seedlings were also investigated. The main results are as follows:1. Photoperiod and temperature had significant effects on both plant germination and growth, and photoperiod was the key factor. The results indicated that the bud dormancy in autumn and winter was induced by the decrease of daytime length. The dormant plants of P. maximowiczii grew under natural day length didn’t sprout in a long period during winter, while sprouted rapidly and grew quickly under extended day length or night interruption treatment. However, long day length didn’t benefit to the growth of P. maximowiczii leading to the increase of length-width ratio of leaves and decrease of root-shoot ratio. Higher temperature promoted the bud germination,while temperature above20℃influenced the growth and development adversely. The plants grown under16hours’day length and15℃temperature kept vigorous and strong growth2. Photoperiod and exogenous gibberellin treatments promoted the bud germination and growth, and effects of exogenous gibberellin were especially significant under short day conditions. During the process of germination, the endogenous hormones content changes were associated with the developmental stage of bud. To the contrary with ABA content, the content of GA3, IAA, ZR in shoot apex first fell and then rose. Spraying exogenous GA3caused the endogenous ABA content decreased significantly.3. Plants of three kinds of seedlings transplanted to Pingquan, Hebei, had experimenced successfully slow growth stage, rapid growth stage, flower bud differentiation stage and dormancy stage. The first time of of flower bud differentiation was synchronous among three seeding ages, with one month’s delaying compared with plants in original habitat. After60days’cold storage (-2℃), there was no significant difference of flowering quality among three kind of seedlings.4. The increase of cold storage time could significantly promoted bud germinating and flowering, as well increase the scape height and flowering rate, which could be explained by the decrease of ABA and IAA content and the increase of GA3, soluble sugar and soluble protein. However, flowering quality among different treatments was not significant, such as floret number and abortive flower number per inflorescence.The results in our research provided scientific basis for cultivation, flowering regulation of P. maximowiczii.