Effects Of Molybdenum Application On Mo-enzymes, Enzymes Relating With Carbon Metabolism And The Constituents Of Cell Wall Of Winter Wheat

Based on the reviews of plant molybdenum (Mo) nutrition, the pot culture experiments were conducted to study the effects of molybdenum on photosynthesis, respiration, and the process of carbon metabolism, as well as the constituents of cell wall of winter wheat (Mo efficient cv. 97003 and Mo inefficient cv. 97014), with Mo applied in the yellow-brown acid soil collected from Xinzhou district, Wuhan, Hubei province. And the results are as follows:1. The molybdenum content in vigorous leave of winter wheat cultivars (Mo efficient cv. 97003 and Mo inefficient cv. 97014) were increased by Mo application and the activity of Mo-enzymes was affected. The activity of nitrate reductase (NR) was increased in the four stages by Mo application, and the activities of aldehyde oxidase (AO) and xanthine dehydrogenase (XDH) decreased in the tillering stage, but increased in later three stages in Mo-fertilized winter wheat.2. Mo application is beneficial to the photosynthesis process. The activities of GAP dehydrogenase and fructose-1,6-bisphosphate phosphatase (FBPase) which partake in photosynthesis were increased by Mo application. And the content of chlorophyll a, chlorophyll b and chlorophyll increased in the tillering stage and the jointing stage but decreased in the heading stage. When Mo was applied, the Caro content increased in the tillering stage; and in the jointing stage, the Caro content in 97003 decaeased, while it is opposite in 97014; in the heading stage, the Caro content in the two winter wheat cultivars decreased. The net photosynthetic rate (Pn) and the transpiration rate increased in the tillering stage and the jointing stage in the Mo-treated winter wheat. The Stomatal conductance (Cs) increased in Mo efficient cv. 97003, while it decreased in Mo inefficient cv. 97014 in the tillering stage, and it is opposite in the jointing stage. Intercellular CO₂ concentration (Ci) also decreased in Mo-treated winter in both the tillering stage and the jointing stage.3. Mo application also affects the activities of respiration enzymes. In the Mo-treated winter wheat, the activity of polyphenol oxidase (PPO) decreased in the four stages; the activity of ascorbic acid oxidase (AAO) decreased in the tillering stage and the jointing stage, but it increased in the heading stage and the milky stage; the activity of glycolic acid oxidase (GO) decreased in the tillering atage, the jointing stage and the heading stage, but it increased in the milky stage. This indicated that the Mo application is beneficial to the accumulation of carbohydrate in winter wheat in the tillering stage and the jointing stage, and therefore, it increased the biologic yield of winter wheat.4. Mo application affects the activity of enzymes which correlated with the constituents of cell wall of winter wheat. IAA oxidase activity decreased in the tillering stage, the heading stage and the minky stage, but increased in the jointing stage in the Mo-treated winter wheat 97003. In the Mo-treated winter wheat 97014, IAA oxidase activity decreased in the tillering stage, the...