| Pot-experiment combined GC-MS analytical technique were applied to investigate the effect of different levels of potassium and magnesium in soil on the change of terpenoid content in tea leaves, and water-culture experiment combined HPLC technique used to study the effect of those in water solution on that of catechin as well. The aim of the investigation was to provide the scientific fundamentals for improvement of tea quality in tea production, and the theoretical basis for application of potassium and magnesium fertilizer in tea culture. Main results are as follows:1) In pot-experiment for potassium treatment, Free and the acid-hydrolyzed low-molecule terpenoids were potentially increased with the increasing of concentration of potassium in the soil, which may be associated with promotion of HMG-COA reductase for potassium in tea leaves, in which, the enzyme plays an important regulating role in "MVP" pathway for synthesis of terpenoids. The acid-hydrolyzed linalool at the investigation levels are all much higher than that of the free, showing high temperature, acid hydrolyzing and so on can promote the release of aroma from the combined compounds. The content of most low-molecule terpenoids decreased under the condition of high levels of potassium application, that may be mainly affected by balance of carbon and nitrogen metabolism in tea tree.2) In pot-experiment for magnesium treatment, with the increase concentration of magnesium in the soil, free and the acid-hydrolyzed low-molecule terpenoid has increased regularity within the scope of the study. The magnesium is directly involved in the synthsis of chlorophyll, which may increase the terpenoid substances of mitochondrial ubiquinone synthesis pathway in the activity of related enzymes.Compared with the high level of potassium,the oxidized linalool content is higher from high levels of magnesium fertilizer application,it has decreased under the condition of potassium, and free and the acid-hydrolyzed low-molecule terpenoid are highest total. In this respect, the effect of magnesium seems more significant for tea cultivation. The IPP is important intermediates in the low terpenoids synthesis pathway.As the IPP is important intermediates.the magnesium have greater influence on the basis of IPP at late terpenoids synthase from the experimental results.3) On the control of the display, the experiment of the hydroponic show that the total of catechins order is Xianyuzao>Shuchazao>Wuniuzao,it related to the variety characteristics. Polyphenols are characteristic of the tea tree carbohydrate metabolism, the sugar can become catechins after a series of metabolic conversion, it shows under the basic level of potassium magnesium varieties on the nutrient element transformation ability. The experiment using three varieties of tea tree, they all set 1.5K and 6.0K level of potassium and magnesium treatment, the experimental results show that no matter which breed, a certain concentration of potassium and magnesium can promote the accumulation of catechins, also the change of the catechins in tea at 1.5K level is higher than 6.0 level. It shows that a certain concentration of nutrients stimulation can be contributed to the accumulation of catechins, but the higer concentration may be limited, for example the EGCG. At the same time, the change in Xianyuzao is particularly prominent, it can not divide with its unique quality.At the experiment of potassium treatment, the first time for sampling period is short, the change rule in the leaves of catechins is not obvious; According to the results of the second sampling, in a hydroponic solution concentration of potassium ascension, all of catechins are increased, and as high as 30%, the EGCG is in particular, it increased almost 80%. This is because of potassium can activate PEPC, it will speed up the formation of shikimic acid and its phosphate, the accumulation of catechins will be more; At the third time sampling, the total of catechins are further increase, the main contributor are EGCG and ECG. But when the potassium concentration increase at the same time, the eaters-catechin GCG and simple catechin C has tendency to decline. The results show that, the right amount of potassium can promote the synthesis and accumulation of catechins, some simple catachins metabolism rate is accelerated when too much, it is not conducive to the accumulation of catechins.4) In the expeiment of magnesium treatment, the law of change with potassium is alike to magnesium by the first two sampling results, but the mechanism is different, magnesium can adjust the conversion of light energy, it will improve the activity of PAL, the accumulation of catechins can be much more; According to the results of the third time sampling, the amount of matter catechins class is still greater than the second, the main cantribution is GA、C、EC and others. With a hydroponic solution concentration of magnesium ascension, especially at a maximum of research, the catechin class also accompanied by a decline in quality, and the biggest drop in GA. |
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