Competitive ability and plasticity of Wedelia trilobata (L.) under wetland hydrological variations.

Growth behavior of different species under different habitats can be studied by comparing the production of biomass, plasticity index and relative competitive interaction. However, these functional traits of invasive species received rare consideration for determining the invasion success of invasive species at wetlands. Here, we examined the effect of water depth at 5 cm and 15 cm (static and fluctuated) with different nutrient concentrations (full-strength (n1), 1/4-strength (n2) and 1/8-strength (n3) Hoagland solution) on functional traits of invasive Wedelia trilobata and its congener native Wedelia chinensis under mono and mixed culture. Water depth of 5 cm with any of the nutrient treatments (n1, n2 and n3) significantly restrained the photosynthesis, leaf nitrogen and photosynthetic nitrogen use efficiency (PNUE) of both W. trilobata and W. chinensis. While, increase in the water depth to 15 cm with low nutrient treatment (n3) reduced more of biomass of W. chinensis under mixed culture. However, relative competition interaction (RCI) was recorded positive for W. trilobata and seemingly W. trilobata benefited more from RCI under high-fluctuated water depth at 15 cm in mixed culture. Therefore, higher PNUE, more competitive ability and higher plasticity may contribute to the invasiveness of W. trilobata in wetlands.

Integrative approach to analyze biodiversity and anti-inflammatory bioactivity of Wedelia medicinal plants.

For the development of "medical foods" and/or botanical drugs as defined USA FDA, clear and systemic characterizations of the taxonomy, index phytochemical components, and the functional or medicinal bioactivities of the reputed or candidate medicinal plant are needed. In this study, we used an integrative approach, including macroscopic and microscopic examination, marker gene analysis, and chemical fingerprinting, to authenticate and validate various species/varieties of Wedelia, a reputed medicinal plant that grows naturally and commonly used in Asian countries. The anti-inflammatory bioactivities of Wedelia extracts were then evaluated in a DSS-induced murine colitis model. Different species/varieties of Wedelia exhibited distinguishable morphology and histological structures. Analysis of the ribosomal DNA internal transcribed spacer (ITS) region revealed significant differences among these plants. Chemical profiling of test Wedelia species demonstrated candidate index compounds and distinguishable secondary metabolites, such as caffeic acid derivatives, which may serve as phytochemical markers or index for quality control and identification of specific Wedelia species. In assessing their effect on treating DSS induced-murine colitis, we observed that only the phytoextract from W. chinensis species exhibited significant anti-inflammatory bioactivity on DSS-induced murine colitis among the various Wedelia species commonly found in Taiwan. Our results provide a translational research approach that may serve as a useful reference platform for biotechnological applications of traditional phytomedicines. Our findings indicate that specific Wedelia species warrant further investigation for potential treatment of human inflammatory bowel disease.

[Induction and in vitro culture of Wedelia trilobata hairy roots].

To study the possibilities for improvement of the ornamental character and production of secondary metabolites by using Wedelia trilobata hairy roots, we investigated the induction of W. trilobata L. hairy roots and its consumption changes of carbon resource, nitrogen resource, phosphate and calcium in the medium during liquid culture. The results showed that hairy roots could be incited from the cut edges of leaf explants 7 days after inoculation with Agrobacterium rhizogenes ATCC15834 and could have an autonomous growth on the medium without phytohormones. The PCR amplification showed that rol genes of Ri plasmid of A. rhizogenes was integrated and expressed into the genome of transformed hairy roots. The hairy root line grew very slowly in 0-7 days, very fast from 7 to 21 days. During the liquid culture of hairy roots, sucrose, NO3(-)-N, PO4(3-) and Ca2+ in the medium could be gradually absorbed and utilized with time. The content of NO3(-)-N in the medium was 5.8% of the initial amount at day 7, while sucrose content was about 50% of the initial amount. At day 35, the NO3(-)-N and sucrose content in the medium was 1.82% and 3.39% of the initial amount, respectively. In combination with Ca2+ consumption, PO4(3-) of the medium was rapidly absorbed and utilized. At day 7, the content of PO4(3-) in the spent medium was only 1.76% of the initial amount; but even at day 35, the content of Ca2+ in the spent medium was still 61.3% of the initial amount. The results presented here had provided the possibilities on improvement the ornamental character and how to prepare optimum medium for large scale cultivation and production of secondary metabolites from W. trilobata L. hairy roots.