Quality Evaluation Of Red Bud Mutation Of 'Ralls' Apple And Preliminary Study On Its Physiological Mechanism Of Red Pigment Development

'Ralls'apple which has the characters of late maturing,good flavors and strong stress resistance, has been popular with pople again. But poor colcouration has always been the main limiting factor of its development. Fruits'coloration affects their commodity value directly. Anthocyanin whose biosythesis is series of enzymatic reaction is the major pigment forming the red of pericarp. Its relationship with related enzymes is quite complicated--the same enzyme performs differently in different species, and the regulation mechanism of red pigment development is different in different plants. The relationship between anthocyanin biosythesis and related enzymes needs further definition. Besides there are many mutations in anthocyanin biosythesis in nature, but the mutation mechanisms in most cultivated plants are not clarified yet. We found a red mutation which had been proved to be bud mutation of'Ralls'in 2005. This red mutatin of'Ralls'has not only provided germplasm resources for breeding but also provided test material for research on red development mechanism in apples.Fruit quality, anthocyanin content and related enzymes were measured in'Ralls'and its bud mutation. Effects of bagging on fruit quality and anthocyanin biosythensis in bud mutation were also studied.The results showed:1. There were no differences in fruit weight,shape index,development period,firmness,titratable acid and aroma component between'Ralls'apple and its red bud mutation,while soluble sugar,sugar-acid ratio and Vc content were higher in the latter. Anthocyanin content in mature fruits was 132.70 U·g-1FW in the latter which was very significantly higher than that in the former (49.40 U·g-1FW).This resulted in the better coloration of the mutation,in which the pigmentation started 60 days earlier than in'Ralls';2. Activities of PAL and UFGT were almost the same between the two materials,but CHI and DFR activities were significantly higher in bud mutation,which was related to the increase of anthocyanin levels in the mutation;3. Bagging treatment significantly increased anthocyanin content in mature fruit of bud mutation,while showed no influnce in other quality properies. Activities of CHI and UFGT increased rapidly and were much higher than in the control after the bag removl.The increase was consistent with the improvement of anthocyanin levels.Above all, there were no significant in fruit qualities in red bud mutation. The main difference between'Ralls'apple and its bud mutation was that the ability of ancyanin sythesis in bud mutation was promoted, which was caused by the improvement on activities of CHI and DFR. The anthocyanin content in bud mutation was significantly higher than in'Ralls', which formed the significant feature of red development in rred bud mutation; The bagging experiment showed that CHI played an important part in anthocyanin biosynthesis in red bud mutation whether under bagging condition or not. So CHI was most closely related to anthocyanin biosynthesis in red bud mutation of'Ralls'apple.