Changes of Metabolites and Flower Bud Differentiation of Camellia azalea

The paraffin section method was used to observe the process of flower bud differentiation of Camellia azalea. Metabolites in the process and the correlation between flower bud differentiation and its external morphology were studied. The results showed that the flower bud differentiation of C. azalea progressed continuously from May to September, during which the flower buds in different differentiation phases could be observed at anytime point. The process of flower bud differentiation could be divided into six phases: physiological differentiation, flower primordium differentiation, sepal primordium differentiation, petal primordium differentiation, stamen and pistil primordium differentiation phases. The process could be identified by the external morphology according to the stable relations between the differential phases and the corresponding morphological characteristics. The content of soluble protein in the flower bud increased at first and then decreased, and soluble sugar content and the ratio of soluble sugar and soluble protein were opposite during the flower bud differentiation. The changes in RNA and total content of nucleic acid were similar to the change of RNA/DNA, which gradually increased with flower bud differentiation and reached a peak in the phase of petal primordium differentiation, then gradually declined in the phase of stamen and pistil primordium differentiation, while DNA content was low and changed gently in the process of flower bud differentiation.