The Structures Of Vegetative Organs And Content Analysis In Salvia Miltiorrhiza

Research was conducted on Salvia miltiorrhiza, a traditional medicinal plant, to investigate the effects of irradiation and shade on the concentration of catalpol in seedlings and rhizosphere. The plants were grown under three irradiances: full light, partial shade (50% full light), and irradiation. The Salvia miltiorrhiza seedlings were harvested and the hydroponic culture solution in the containers was collected on days 3, 6, 9, 12, 15 after treatment respectively for determination of catalpol. The results showed that irradiation increased the concentration of catalpol in leaves rapidly at the early stage. Then, instead of increasing, the concentration of catalpol decreased a little. In contrast, the catalpol content in Salvia miltiorrhiza leaves was reduced under partial shade. Similar trends were observed in roots and stems of Salvia miltiorrhiza under irradiation and shade. The concentration of catapol in medium in which full-light, shade and UV-irradiated seedlings were grown all increased with time. But the concentration of catapol in medium of irradiated seedlings was greater than that of full-light seedlings, the concentration of catapol in medium of shade seedlings is lower than that of full-light seedlings. Therefore, irradiation increased both production of catalpol in Salvia miltiorrhiza seedlings, and secretion of catalpol into Salvia miltiorrhiza rhizosphere. In contrast shading decreased not only production of catalpol in Salvia miltiorrhiza seedlings, but also secretion of catalpol into Salvia miltiorrhiza rhizosphere.Irradiation increased the concentration of catalpol in leaves of Salvia miltiorrhiza seedlings rapidly at the early stage. Then, instead of increasing, the concentration of catalpol decreaced a little. The production of catalpol was, therefore, probably increased at the early stage by irradiation due to induceing stress response of plant, increaceing more plant secondary metabolites to guard against irradiation damage. However, a further extension of time to radiation, the leaves were damaged by the radiation, which affected not only the photosynthetic efficiency but the production of the secondary metabolites. Therefore, a further extension of time to UV radiation, the catalpol content in Salvia miltiorrhiza leaves did not increase significantly, or even decreased. In contrast, the catalpol content in Salvia miltiorrhiza leaves was reduced under partial shading, suggesting that shading affected photosynthesis, then the synthesis of secondary metabolites. There was an accumulation of catalpol in the medium in which Salvia miltiorrhiza seedlings were grown. As described in the Materials and methods section, in the present experiments only R. glutinosa roots were immersed in the medium. Thus, the Salvia miltiorrhiza seedlings probably secrete catalpol from their roots into the medium. The results described in the present research showed that the concentration of catalpol in the medium in which UV-irradiated seedlings were grown was greater than that in the medium in which full-light seedlings were grown.There are few reports on the effect of irradiation on catalpol concentration, but it was noted that irradiation increased not only production of momilactone B in rice seedlings but also secretion of momilactone B into rice rhizosphere. On the contrary, the concentration of catalpol in the medium in which shaded seedlings were grown was lower than that in the medium in which full-light seedlings were grown. These results suggest that irradiation increased both production of catalpol in Salvia miltiorrhiza seedlings, and secretion of catalpol into Salvia miltiorrhiza rhizosphere. In contrast shading decreased not only production of catalpol in R. glutinosa seedlings, but also secretion of catalpol into Salvia miltiorrhiza rhizosphere. So if high concentration of catalpol in soil is the reason for Salvia miltiorrhiza continuous cropping obstacle, intercropping with tall crop can be taken in agricultural production to shade Salvia miltiorrhiza, so as to reduce secretion of catalpol into Salvia miltiorrhiza rhizosphere.