ABSTRACT
In this study, the growth index including plant height, compound leaf area, specific leaf area, leaf water content, number of branches, and leaf biomass per plant and the icariin flavonoids such as epimedin A, epimedin B, epimedin C and icariin of Epimedium pseudowushanense were determined on 30 d and 60 d under light intensity(18.2±2.5) μmol·m~(-2)·s~(-1)(L1) and(90.9 ±2.5) μmol·m~(-2)·s~(-1)(L2), and white light as control, red light, blue light and yellow light were used as three light quality treatments, to study the effect of light quality on the growth and flavonoids accumulation of E. pseudowushanense. The E. pseudowushanense was sui-table for growth under L1 light intensity, the blue light treatment significantly reduced the leaf area, but had little effect on the stem height, the red light treatment and the yellow light treatment had no obvious effect on the stem height and leaf area, but the yellow light treatment significantly increased the germination of new branches, and had a sustained promoting effect, and the biomass was significantly higher than the white light treatment at 60 d. The content of icariin flavonoids in red light, blue light and yellow light treatment was higher than that in white light treatment at 30 d and 60 d under L1 light intensity, while yellow light treatment promoted the synthesis of icariin flavonoids to the largest extent, which was 1.8 and 1.9 times of white light treatment(30 d and 60 d).Under L2 light intensity, the effect of strong light on promoting stem germination became the main factor, while the yellow light treatment showed no significant effect on promoting stem germination, and the red light treatment exhibited a significant effect on reducing leaf area. Icariin flavonoids under red light, blue light and yellow light treatment were all lower than that under white light treatment, that is, the effect of white light treatment on the synthesis of icariin flavonoids is better than red light, blue light and yellow light treatment. When the time of strong light treatment was longer, the degradation range of icariin flavonoids in other light treatment appeared, while red light treatment promotes the synthesis of icariin flavonoids. Therefore, the influence of light quality on E. pseudowushanense is quite different under different light intensity, no matter from growth index or flavonoid content index. The results support that the biomass and icariin flavonoid content can be increased by providing appropriate red and yellow light.
Subject(s)
Drugs, Chinese Herbal , Epimedium , Flavonoids , Plant LeavesABSTRACT
Epimedium is a widely used medicinal plants. Due to excessive use of wild resources and resource constraints, artificial cultivation is the only way to achieve sustainable use of resources. E. pseudowushannense is intended to achieve the first cultivated species, but plant production technology is not yet fully mature.The diurnal variation of photosynthetic and eco-physiological characteristics of E. pseudowushannense in different growing age was studied by the CI-340 Portable Photosynthesis System under natural conditions. The net photosynthetic rate (Pn), stomatal conductance (C), intercellular CO2 concentration (Ci), photosynthetically active radiation (PAR), relative humidity (RH), air temperature (Ta), apparent mesophyll conductance (ALMC), transpiration rate (E), leaf temperature (Tl), water use efficiency (WUE) and other photosynthetic physiological factors and environmental factors were measured. The obtained data was analyzed by correlation analysis, path analysis and stepwise multiple-regression analysis to explore the relationship between net photosynthetic rate and physiological and ecological factors. The results show that： ①The daily variation of the Pn, E, ALMC, C of E. pseudowushannense in different growing age took on"two peak type", the Pn was with an obvious midday depression phenomenon at noon.②The Pn, ALMC and C of annuals' were significantly higher than biennial or three-year; but the Ci was basically a three-year > biennial> annual.③The correlation analysis, path analysis and stepwise regression analysis showed that ALMC, Ci, Ta might played important role in the Pn and ranked as ALMC>Ci>Ta.
ABSTRACT
As an important secondary metabolites of medicinal plant, flavonoids plays a very important role on itself including light protection and antioxidant. Light is one of the important environmental factors which impacts the secondary metabolites of plant and has a significant impact on biological synthesis of flavonoids. This paper reviews the recent progress of the effects of light on flavonoids on the plants focusing from light intensity and light quality, and summarizes briefly functions of the phenylalanine ammonia lyase (PAL) in plant secondary metabolism and the upstream key enzyme chalcone synthase (CHS) in flavonoid biosynthetic pathway.