Wanxia Yang

Effect of light regime and provenance on leaf characteristics, growth and flavonoid accumulation in Cyclocarya paliurus (Batal) Iljinskaja coppices

BackgroundAs a highly valued and multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medical use. However, limited information is available on its genotype selection and cultivation for growth and phytochemicals. Responses of growth and secondary metabolites to light regimes and genotypes are useful information to determine suitable habitat conditions for the cultivation of medicinal plants.ResultsBoth light regime and provenance significantly affected the leaf characteristics, leaf flavonoid contents, biomass production and flavonoid accumulation per plant. Leaf thickness, length of palisade cells and chlorophyll a/b decreased significantly under shading conditions, while leaf areas and total chlorophyll content increased obviously. In the full light condition, leaf flavonoid contents showed a bimodal temporal variation pattern with the maximum observed in August and the second peak in October, while shading treatment not only reduced the leaf content of flavonoids but also delayed the peak appearing of the flavonoid contents in the leaves of C. paliurus. Strong correlations were found between leaf thickness, palisade length, monthly light intensity and measured flavonoid contents in the leaves of C. paliurus. Muchuan provenance with full light achieved the highest leaf biomass and flavonoid accumulation per plant.ConclusionsCyclocarya paliurus genotypes show diverse responses to different light regimes in leaf characteristics, biomass production and flavonoid accumulation, highlighting the opportunity for extensive selection in the leaf flavonoid production.

Chemical Fingerprint and Multicomponent Quantitative Analysis for the Quality Evaluation of Cyclocarya paliurus Leaves by HPLC–Q–TOF–MS

Cyclocarya paliurus is an edible and medicinal plant containing various bioactive components with significant health benefits. A combinative method using high-performance liquid chromatography (HPLC) fingerprint and quantitative analysis was developed and successfully applied for characterization and quality evaluation of C. paliurus leaves collected from 18 geographical locations of China. For the fingerprint analysis, 21 common peaks were observed among the 18 samples, and these peaks were identified by high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC–Q–TOF–MS), while a simultaneous quantification of 16 markers was conducted to interpret the variations of contents of these bioactive compounds among the C. paliurus leaves from different geographical locations. Quantification results showed that the contents of these sixteen investigated compounds varied greatly among the leaves from different locations. The developed new method would be a valuable reference for further study and development of this bioactive plant.

Seasonal variation of microelement contents in leaves of Cyclocarea paliurus among the provenances

Cyclocarya paliurus as a multiple function plant can accumulate biologically important microelement elements. To reveal the variation of selected microelement concentrations in leaves of C. paliurus provenances during the growing season, 12 C. paliurus provenances in the field trial were sampled five times at approximately 1-month intervals. The method of inductively coupled plasma optical emission spectrometer (ICP-OES) was employed to determinate average concentrations of Fe, Mn, Zn, Cu and Se in leaves of 12 C. paliurus provenances. The results show that on average, the concentrations of five microelement in the leaves follows an order of Fe > Mn > Zn > Cu > Se. Variance analysis shows that there are significant differences in Fe, Mn and Zn concentrations among the twelve provenances (p<0.05), while there is no significant difference between Cu and Se concentrations. A significant difference was also observed in the concentrations of five microelements at the different sampling times (p<0.001), but the mean concentrations for each microelement showed different temporal dynamic patterns. Meanwhile, a significant correlation between concentrations of Se and other measured microelements was detected in the leaves of C. paliurus, except for Mn. Obtained results not only demonstrated that leaves of C. paliurus exhibited higher levels of microelements (Fe, Mn, Cu, Zn and Se), but also provided a basis for breeding strategies of superior provenances with rich content of microelements, and choosing optimum harvesting time for food industry in future.

Cytochemical localization of ATPase and sub-cellular variation in mesophyll cell of Cyclocarya paliurus seedlings under iso-osmotic stress and calcium regulation.

The ultrastructural distribution and active location of ATPase and the ultrastructural variations were investigated in mesophyll cells of Cyclocarya paliurus seedlings after iso-osmotic salt/water treatments in combination with calcium regulation. C. paliurus seedlings were treated with five groups (control, 85 mM NaCl, 85 mM NaCl + 12 mM Ca(NO3)2, PEG iso-osmotic to 85 mM NaCl and PEG iso-osmotic to 85 mM NaCl +12 mM Ca(NO3)2) in a hydroponic system in a phytotron. Results show that under normal growth conditions, the ATPase activity was low and the enzyme was primarily located on the nucleus. After 12 days of iso-osmotic salt/water treatments, ATPase activity on the tonoplast increased. Osmiophilic globules for iso-osmotic water treatment were greater than that for iso-osmotic salt treatments. The ATPase activity increased and was mostly transferred onto the nucleus for calcium regulation treatment under iso-osmotic salt/water stresses, and the osmiophilic globules significantly decreased under iso-osmotic water stress with calcium regulation. The ATPase located on the nucleus indicated that the degree of salt/drought damage that seedlings suffered was slighter, while the amount of the enzyme located on the tonoplast showed that the degree of salt/drought damage there was more serious. After 4 and 20 days of isoosmotic treatments, the injury suffered by the leaf ultrastructures of C. paliurus seedlings for iso-osmotic treatment with calcium regulation was lower than those without calcium regulation, especially for the iso-osmotic water treatments. Preliminary analysis suggests that the injury suffered by C. paliurus seedlings was lower for iso-osmotic salt treatments than for iso-osmotic water treatments, while the effect of calcium regulation under iso-osmotic water stress was greater than that of the iso-osmotic salt stress.

Light quality affects flavonoid production and related gene expression in Cyclocarya paliurus

Understanding the responses of plant growth and secondary metabolites to differential light conditions is very important to optimize cultivation conditions of medicinal woody plants. As a highly valued and multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medical use. In this study, LED-based light including white light (WL), blue light (BL), red light (RL), and green light (GL) were used to affect leaf biomass production, flavonoid accumulation and related gene expression of one-year C. paliurus seedlings in controlled environments. After the treatments of 60 days, the highest leaf biomass appeared in the treatment of WL, while the lowest leaf biomass was found under GL. Compared to WL, the total flavonoid contents of C. paliurus leaves were significantly higher in BL, RL, and GL, but the highest values of selected flavonoids (kaempferol, isoquercitrin and quercetin) were observed under BL. Furthermore, the greatest yields of total and selected flavonoids in C. paliurus leaves per seedling were also achieved under BL, indicating that blue light was effective for inducing the production of flavonoids in C. paliurus leaves. Pearsons correlation analysis showed that there were significantly positive correlations between leaf flavonoid content and relative gene expression of key enzymes (phenylalanine ammonia lyase, PAL; 4-coumaroyl CoA-ligase, 4CL; and chalcone synthase, CHS) in the upstream, which converting phenylalanine into the flavonoid skeleton of tetrahydroxy chalcone. It is concluded that manipulating light quality may be potential mean to achieve the highest yields of flavonoids in C. paliurus cultivation, however this needs to be further verified by more field trials.

Antidiabetic Effect of Cyclocarya paliurus Leaves Depends on the Contents of Antihyperglycemic Flavonoids and Antihyperlipidemic Triterpenoids

Cyclocarya paliurus has been used commonly to treat diabetes in China. However, the effective components and the effect of plant origin remain unclear. In this study, C. paliurus leaves with different chemical compositions were selected from five geographical locations, and their effects on streptozotocin (STZ)-induced diabetic mice were evaluated with both ethanol and aqueous extracts. Glucose levels, lipid levels, and biomarkers of liver and kidney function were measured. The principal components of both C. paliurus ethanol and aqueous extracts from different geographical locations differed quantitatively and qualitatively. Results showed that C. paliurus extracts with better antihyperglycemic effects were characterized by higher contents of total flavonoids, especially quercetin-3-O-glucuronide and kaempferol-3-O-glucuronide. Furthermore, significantly negative correlations were found between triterpenoids contents and lipid levels. These results revealed the potential antihyperglycemic capacity of C. paliurus flavonoids and the antihyperlipidemic effect of C. paliurus triterpenoids. Thus, we suggest that the composition of C. paliurus compounds might help to design therapeutic alternatives for the treatment of diabetes mellitus. However, geographic origins and the extraction solvents can also affect the effectiveness of the treatment as these factors influence the chemical compositions and thereby the biological activities.

Genotypic variation in tree growth and selected flavonoids in leaves of Cyclocarya paliurus

Cyclocarya paliurus is a valuable medicinal tree species in China. However, limited information is available on its genotype selection and cultivation for improvement of growth and health-promoting phytochemicals. To contribute to improved knowledge of the potential use of the species, 33 families of C. paliurus were assessed with respect to genotype on growth and flavonoid content in the leaves, and the relationship between growth and flavonoid accumulation was examined. Growth and flavonoid content varied significantly among different families, and isoquercitrin was the main component of the individual flavonoids, followed by kaempferol and quercetin. Both total and individual flavonoids showed seasonal variation, with the mean highest contents of quercetin and isoquercitrin in July but the highest kaempferol content in October. Correlation analysis showed that tree height and diameter at breast height of C. paliurus were negatively correlated with the contents of quercetin and kaempferol in the leaves, whereas no significant correlation between tree growth and total flavonoid content was detected. Hierarchical cluster analysis based on the parameters of tree growth and leaf flavonoid contents indicated that 33 families of C. paliurus were classified into four distinct groups. Results from this study are valuable for identifying superior families for a specific site and provide a basis for C. paliurus breeding strategies for flavonoid production.