Study on physiological and biochemical characteristics during in vitro flowering of Rosa ‘Yametsu-Hime’

In vitro flowering can greatly shorten the nutritive growth years of plants, and it is an effective model system to study flower formation, development and senescence. Under this condition, the physiological and biochemical characteristics of the flower development process can be investigated, which can provide a theoretical basis for analyzing the intrinsic mechanism of flower formation. This study took Rose ‘Yametsu-Hime’ as the research subject, and measured the contents of endogenous hormones, soluble sugars and soluble proteins in four stages of its flower development, respectively, to explore the correlation between the development process of rose and the contents of endogenous hormones, carbohydrates and nutrients. On this basis, suitable hormones, carbohydrates and nutrients were selected to explore the effects of external factors on in vitro flowering of rose. The results showed that (1) cytokinin (CTK), abscisic acid (ABA) and indole-3-acetic acid (IAA) all had positive effects on floral bud formation during flower development in Rose ‘Yametsu-Hime’, and the effects of CTK and ABA were stronger. High concentrations of brassinosteroid (BR) had a negative effect on flower development. High ratios of CTK/IAA and ABA/IAA accelerated the decay of the rose; high ratios of CTK/ABA favored the formation of floral buds, and low ratios favored the formation of floral organs. High ratios of ABA/BR favored the formation of floral buds as well as the formation of floral organs. The content of soluble sugars and soluble proteins reached the maximum value at the full blooming stage, which had a certain effect on the isolated flowering. (2) Adding hormones, sugars and nutrients to the culture medium all had a positive effect on in vitro flowering of rose, but the addition of cytokinin BA had the strongest effect. When the concentration of BA was 1.5 mg L^− 1, the floral bud induction rate and flowering rate could reach 91.11% and 79.73%, respectively.