| Cabernet Sauvignon (V.vinifera.L) and Chardonnay (V.vinifera.L) were selected as experimental materials, dormancy buds were treated by 3 % Domex and clear water (CK), to elucidate the depth state of dormancy, water status, active oxygen metabolism, anti-oxidation system and phenolic compounds and related enzymes in bud dormancy breaking. Laboratory experiment was conducted to study the changes of six individual phenolics in Pinot Noir's dormancy releasing stage. The main results are as follows:Different varieties have the different state of bud endo-dormancy in the same stage. Chardonnay which is an early maturity variety comes into deep dormancy on Dec. 20th, and bud dormancy starts to release gradually from Jan. 29th; the late Cabernet Sauvignon's deep dormancy stage is from Jan. 10th to Feb. 18th and bud dormancy starts to release gradually.The grape bud dormancy could be broken by 3 % Domex treatment, the time of CH bud germination advanced 13d, and the time of CS advanced 20d.With the deepening of bud dormancy, The total water and free water content in bud were decreasing, bound water and the rate of bound water/free water were increasing, three kinds of water showed a contrary trend in dormancy releasing period comparing with the previous stage. The changes of water content showed a similar trend between Chardonnay and Cabernet Sauvignon in the whole dormancy period, however, the time of Chardonnay'peak value is 20 days earlier than the time of Cabernet Sauvignon', which might be associated with Chardonnay's early entrance into the deep dormancy. After Cyanamide's treatment, free water droppred rapidly, and bound water increased. It also elucidated that the rate of bound water/free water is an index expressing the depth of bud dormancy.The content of active oxygen O2?·and H2O2 had a gradual increase in the early dormancy stage, reaching the peak value at the deep dormancy, and decreased in the stage of dormancy release. Cyanamide's treatment caused active oxygen contents to rise comparing with the control during the early dormancy stage, and there is no difference during the later dormancy. SOD activity was dropping at all times in the process of dormancy, and then started to rise during the dormancy release. Cyanamide's treatment delayed Peak value of SOD activity. POD and CAT activity was rising during the early dormancy stage, then POD started to drop during the dormancy release and CAT activity maintained a high level till bud sprouting, Cyanamide's treatment made POD activity drop quickly. A feeble ASA-GSH cycle manifested during the early stage, then ASA-GSH cycle was activated gradually, Cyanamide's treatment could enhanced this cycle during dormancy release.During the early dormancy stage, PPO, PAL activity and total phenolic content were increasing with the accumulation of low temperature, PAL activity and total phenolic decreased and showed a similar trend during the dormancy release, from a overall viewpoint, PPO activity had a limited drop in this stage, Cyanamide's treatment had no effects on three parameters above-mentioned.During the Pinot Noir's whole dormancy stage, the contents of Protocatechuic acid, (+)-Catechin, (-)-Epicatechin, (-)-Epicatechin-3-O-gallate, Trans-Resveratrol showed a downward trend, especially for (-)-Epicatechin, its content decreased by nearly 6 times, the content of Trans-Resveratrol showed a rapid rise in the first eight days, dropping dramatically later, and maintained a rather low level before bud break. The content of Gallic acid in bud showed a rise trend as a whole. |
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