| The shoots of Red Toona Sinensis Roem after selected and graded were packaged into polyethylene bags and then stored at 1±0.5℃ to investigate the changes of physiology, biochemistry and quality occurred in bud, stem and leaf during storage period. The Vc, reducing sugars , PPO, POD, PAL, Phenol and BQ were determined, to intend to understand the senescent mechanicsm. The plant growth regulators such as (50ppm) naphthalene acetuc acud (NAA), (50ppm )gibberellin (GA), (100ppm) ethylene (C2H4), (0.8%) citric acid (CA), (50ppm) 2,4-dichlorophenoxy acetic acid (2,4-D) and (50ppm) 6-benzyladenine (6-BA) were used to the shoots to find the effect on the metabolism of phenols and the activity of related enzymes. The main results were showed as follows:1. The content of Vc of Toona Sinensis Roem was extremely high, but it is easy to lost. After fifteen days' storage, the loss of Vc in leaves was especially serious from 30.82mg/100g to 11.51mg/100g, while that of stems lost 21.95%. The content of reducing sugar increased to some extent at first, and then reduced gradually during storage. The decreases of reducing sugar in red Toona Sinensis Roem was not significantly except the stem.The contents of different dietary fiber of Toona Sinensis Roem were pretty high, and they varied from leaves to stems to buds. The content of dietary fiber increased at the beginning, and then reduced, except crude fiber of leaves and stems that increased gradually. The decrease of Vc and reducing sugars combined with increase of various kinds of fibers resulted in quality deterioration.2. The color of Toona Sinensis Roem was mauve and bright at the beginning of storage, and it became to turn light and dull gradually, what's more, there was obvious browning at the end of storage. In general, the redder the color is, the longer Toona Sinensis Roem can be stored. The aging rate of different of Toona Sinensis Roem was not the same. The color of buds changed most rapidly, while that of stem smoothly, so was its aging rate.3. The activities of PPO, POD and PAL of Toona Sinensis Roem were relatively low,and they differed among buds, leaves and stem. The activities of PPO of different position of Toona Sinensis Roem is stem > bud > leaf, and that of POD is leaf > stem > bud, both enzymes remained the situation during storage. PAL in buds and stems generally decreased with the prolong of storage ,while that in leaves was very small at the beginning of storage and increased sharply and took first place in the middle of storage ,and continued to increase to the end of storage.4. The content of total phenol in different positions of Toona Sinensis Roem reduced at the beginning, and then went up in middle period, and increased to some extent on later stage and tended towards stability gradually;While the content of free phenol dropped fast for earlier stage, and showed in the middle and later periods, and it was very few at last(<5.0μg/gFW).The results of thin layer chromatography of silica gel G showed that the main enzymatic browning substrates in Toona Sinensis Roem was chlorgenic acid.5. Among 6 on exogenous plant growth regulators, 6-BA, 2,4-D and CA had good impact on regulating for phenol of Toona Sinensis Roem , especially 6-BA,which can significant elevate TP and reduce FP content.The activities of POD and PPO by the treatment of 2,4-D, CA, GA. NAA and C2H4 were higher than that of CK, indicating that 6-BA was helpful for the control of color for the storage of the products.
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