Effects Of Water And Light On Growth And Medicinal Quality Of Glechoma Longituba

Glechoma longituba (Nakai) Kupr. (Labiatae) is a perennial plant distributed mainly in China, Russia and North Korea. Glechomae herba, the dried above-ground part of G.longituba, is usually used for the treatment of lithagogue, diuretic, cholagogue, detoxicating,heat-clearing, swelling and pain caused by traumatic injury. A few studies on the pharmacological activities of Glechomae herba have been reported, including antifugal,antioxidant, anti-tumor and anti-diarrhea activities. It is widely used in clinic, and has been made into several Chinese patent medicines as the key raw materials, such as Lithagogue Granules (Paishi-Keli in Chinese) and Cholagogue Capsule (Danle-Jiaonang in Chinese).With the increasing market demand, its wildlife resources reduced and could not meet the market demand. However, the yield and quality of Glechomae herba could not be obtained simultaneously in its main production area, where the extensive planting technology was applied. As a result, many problems associated with actual production could not promote the development of traditional Chinese medicine. Thus, the responses of G. longituba to water, light intensity and light quality at different levels were investigated,and provided theoretical base for its good agricultural practice (GAP). The main research contents and results were as follows:1. Five water gradients (95%-100%, 80%-85%, 65%-70%, 50%-55% and 35%-40% of field capacity) were designed by weighting method, and the effects of different water treatments on growth, anatomy structure, physiolgy and medicinal quality of G. longituba were investigated in a pot experiment. The results showed that the seedlings had thick stem and leaf, much more chloroplast, grew better and accumulated higher biomass at 80%-85%of field capacity, but grew worst at 35%-40% of field capacity. Water stress increased the contents of MDA, proline, soluble sugar, and improved the resistance of the plants. The content of total flavonoids in G. longtituba at 95%-100% of field capacity was the highest,but the yield was the highest at 80%-85% of field capacity. The contents of ursolic acid and oleanolic acid increased, then decrease with the decrease of soil water content; the contents and yields of these two chemical substances both reached the maximum values at 80%-85%of field capacity. Overall, G. longituba could obtain higher yield and better quality at 80%-85% of field capacity.2. Light intensity control experiments were performed with shade nets to achieve a different light intensity gradient: 100% (control), 75%, 58%, 33%, 16% and 9% of full sunlight irradiance, and the effects of light intensity on growth, anatomy structure,physiolgy and medicinal quality of G. longituba were investigated in a pot experiment. The results showed that G. longituba was an extreme shade-tolerant plant and could adjusted its morphology and structure to accommodate the different light environments. However, high light inhibited the growth and reduced the accumulation of dry matter in G longituba, the development of chloroplast and accumulation of dry matter were the most appropriate at 16%-33% of full sunlight irradiance. The maximum net photosynthetic rate (Amax) in leaves firstly increased, then decreased with the decrease of light intensity, and reached the highest maximum values at 33% and 16% full sunlight. In shade treatments, the ability to utilize the weak light of the leaves increased, and the degree of being inhibited by strong sunlight decreased. The structure and function of photosynthetic organ were damaged at full sunlight, and the photosynthetic rate was reduced by non-stomatic factor. Shade leaves had lower dissipation of excess excitation energy, higher activity of transfering electron, much more energy of absorbing, capturing and transfering per unit area in PS ? , and the actual photosynthetic efficiency was improved. Performance indexes on absorption basis (PIABS)in shade treatments were higher than that at full sunlight, and reached the maximum value at 33% and 16% full sunlight. Shade increased the contents of ursolic acid and oleanolic acid, and the yields reached the maximum values at 33% and 16% full sunlight irradiance.However, shade treatment induced the content of total flavonoids in G. longituba. In short,33% and 16% full sunlight irradiance treatments could get higher yield and better quality.3. The seedlings were covered with white (control), red, yellow, blue and green color films, and the relative light intensity under the films were all maintained at 36.61%-38.42%of full sunlight irradiance. The effects of different light quality environments on growth,anatomy structure, photosynthesis and medicinal quality of G. longituba were investigated in a pot experiment. The results suggested that blue and red film treatments were beneficial to the development of the leaf and stem, which had thicker leaf and stem, compact leaf tissue, much more chloroplast in leaves, and well-developed vascular cylinder in stems.Blue film treatment had the highest dry matter accumulation, and well-developed chloroplast with regular grana lamellae, more appressed thylakoids and large starch grain.Red film treatment was beneficial to the accumulation of starch, but inhibited the export of photosynthetic production. Blue film treatment increased the length and width of the stoma,the white film treatment increased the stomatal density. Higher Amax, dark respiration rate,light saturation point and compensation point appeared in blue film treatment. The diurnal variation of net photosynthetic rates in different film treatments presented bimodal curves.The leaves in blue film treatment had higher photosynthetic activity, well-developed structure and function in photosystem II, the lowest dissipation of excess excitation energy,the highest Amax and higher PIABS, followed by green film, red film, white and yellow film treatments. Blue film treatment could get higher content and yield of total flavonoid,followed by green film treatment. Green film treatment was appropriate to the accumulation of ursolic acid content, but the yield of ursolic acid per plant was the highest in blue film.Blue film, green film and red film treatments improved the accumulation of oleanolic acid contents, but the improvement of blue film treatment on the yield of oleanolic acid was the highest in blue treatment. Therefore, blue film treatament was the most propitious to improve the yield and medicinal quality of G longituba.