| The research object was Alisma plantago-aquatica Linn, from sichuan in this experiment. This study adopt the single factor randomized block design, research for the different of bolting and wiping off bolting plants which including the accumulation and distribution of dry matter, the variation of carbon and nitrogen metabolites in leaf source and tuber storage, the changing process of medicinal composition content in different parts of plant and the quality of medicine.The study revealed the influence of reproductive growth to the production, quality and their formation mechanism of A. plantago-aquatica, provided a potential reference for cultural techniques of high yield and quality and breeding of A. plantago-aquatica, while offered some application instruction for better utilization of plant resources.The main research results are as follows:1. The effects of reproductive growth on the dry matter accumulation and distribution of A. plantago-aquatica were obvious. Reproductive growth in bolting and squaring period can promote the increasing of dry weight of tubers and root. As the plant blooming and fruiting while main storage center shift its role gradually disappear. But it can significantly increase the total plant capacity and improve the total plant biomass. In other word, it can reduce the yield of leaves, tubers, and fibrous root but increase total plant production, which increased by11.7%. Cuting off reproductive growth impacts mildly on the dry matter accumulation trends of leaf, root and tuber in the whole growth stages, but can significantly increase the dry matter accumulation and distribution ratio of leaf, tuber and root, whose yield increased by30.9%,19.7%and17.6%, and whose distribution ratio increased by41.9%,34.3%and32.3%. The effect on tuber drying rate is not obvious whether wiping of bolting.2. The effects of reproductive growth on the carbon and nitrogen metabolism of A. plantago-aquatica’s leaf source and tuber storage were obvious. Reproductive growth can promote the accumulation of leaf soluble protein content, decrease the synthesis of leaf starch and strengthen to the transport of sucrose from leaf to tuber and inflorescence. At the same time it can accelerate plant senescence, promote the transfer of nitrogen from leaf to tuber at later stage of leaf growth and increase the crude protein, soluble protein content of tuber and the late starch accumulation of tubers. Cuting off the reproductive growth can extend the accumulation time of the high leaf nitrogen level, keep the plant on more robust growth in October and November; it also improve in a large extent leaf soluble sugar and starch accumulation, enhance the supply ability from leaf source to tuber storage and improve leaf C/N value at later growth stage; at the same time it can reduce the sucrose content in the tubers, significantly improve the starch storage speed in tuber during late November and early December and increase the accumulation of soluble sugar content in tuber at middle and later growth stage,which obviously increase the tuber C/N value in the critical period of yield formation.3. The effects of reproductive growth on the medicinal component content at different parts of A. plantago-aquatica were obvious. Reproductive growth can increase the transform of leaf sucrose to medicinal components and improve the leaf alisol B-23-acetate and total triterpenoid content at harvest time. At the same time it can accelerate the transfer of triterpene composition from tuber to inflorescence and fibrous root so that inflorescence maintain high alisol B-23-acetate and total triterpenoid content, reduce the content of the tuber alisol B-23-acetate and total triterpenoid content at harvest time. Cuting off reproductive growth can enhance the transform of leaf and tuber soluble sugar to medicinal ingredients, promote the transfer of alisol B-23-acetate from leaf to the tuber, thus it improve the content of the tuber alisol B-23-acetate and total triterpenoid content at harvest time. The effect on the total triterpenoid content of fibrous root is not obvious whether cutting off reproductive growth.4. The effects of reproductive growth on different quality indicators of A. plantago-aquatica were different. But their qualities coincide with the requirements of the current "Chinese pharmacopoeia". Retaining reproductive growth is conducive to improve the medicinal material diameter and single volume, which increased by4.1%and7.7%. Cutting off reproductive growth is beneficial to increase tuber number, height and total volume, which increased by28.6%,10.0%and20.9%; Significantly reduce the total ash and acid insoluble ash content, which reduced by5.7%and39.2%; Improve the medicinal ethanol extract content, alisol B-23-acetate and total triterpenoid content, which increased by6.7%,10.0%and21.9%.5. The relationship between the source and sink organs and the relationship between them and the carbon and nitrogen metabolism indexs of leaf and suber of A. plantago-aquatica were significant.The size of leaf source and the size of root source, the size reproductive storage and the size of nutrition storage were extremely significant positive correlation. Leaf source growth was mainly affected by nitrogen. The plant fibrous root was more flourishing, with more absorption and transfer volume of nitrogen, the leaves grow stronger. The size of tuber storage was directly related to leaf source carbohydrates supply capacity (the soluble sugar content) and the accumulation of tuber nitrogen compounds, which plays a positive promoting role. The effect of leaf nitrogen metabolism on the leaf carbon metabolism and tuber carbon and nitrogen metabolites was extremely obvious, the accumulation content of leaf nitrogen was more the later ones’ content were lower, except that the accumulation of starch whose effect is not significant.6. The relationship of medicinal composition at different parts and the relationship between them and the carbon and nitrogen metabolism indexs of leaf and suber of A. plantago-aquatica were significant. The alisol B-23-acetate content of A. plantago-aquatica leaf was depended on its total triterpenoid content and tuber alisol B-23-acetate content. The medicinal composition content of leaf and tuber was obviously affected by leaf and tuber carbon and nitrogen metabolites. leaf soluble sugar content and C/N ratio were higher, the more transformation for leaf medicinal composition, also the content of alisol B-23-acetate transfering to tuber was more. The high content of tuber nitrogen compounds has a positive promoting role to the increasing of alisol B-23-acetate content in leaf and tuber, while high levels of leaf nitrogen compounds has reverse effects on the increasing of alisol B-23-acetate content in leaf and tuber.7. Based on the above research results, it should be applied enough nitrogen early days during the process of cultivation. During the tuber yield formation stage, it was supposed to gradually reduce the nitrogen application and take some artificial measures such as wiping off bolting to promote the accumulation of leaf soluble sugar content for improving the yield and quality of A. plantago-aquatica. The A. plantago-aquatica strains should be choose which have suitable leaf amount under the same habitat and cultivation measures, as the same time whose leaf soluble sugar content and tuber nitrogen content are higher at later stages of plant growth. When we cultivate the seeds of A. plantago-aquatica, we should choose the large and heavy tubers, meanwhile which had high content of soluble sugar (whose bleeding liquid was sticky and which taste sweet relatively). The A. plantago-aquatica leaf and inflorescence had great development and utilization value. The leaves and inflorescence should be collected at different period, the inflorescence could be gathered around November21, the leaves at the harvest period of tuber. |
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