Assessment of the current distribution, dispersal trends and impacts of invasive species in Bana - Nui Chua Nature Reserve, Vietnam

Invasive species threaten the biodiversity and the function of ecosystems. Drone image, satellite images, and image analysis software were used to create the map of invasive distribution and the potential spreading of invasive plants. 13 most invasive plants were identified with 11 species listed as invasive species in Southeast Asia and 5 of them in the 100 world’s invasive species by IUCN. Three species Merremia boisiana (Gagn.) van Ooststr., Ipomoea eberhardtii Gagn, and Mimosa pigra were identified as the species with high-ranking impacts on biodiversity and ecosystem biodiversity in Ba Na - Nui Chua Nature Reserve (BNNR). Ipomoea eberhardtii Gagn shows the highest spreading rate at 0.65 ± 0.06 ha/month, followed by Merremia boisiana (Gagn.) van Ooststr) and Mimosa pigra at 0.12 ± 0.01 ha/month and 0.01 ± 0.001 ha/month respectively. Fresh biomass of Ipomoea eberhardtii Gagn; Merremia boisiana (Gagn.); Mimosa pigra and Sphagnetola trilobata (L.) Pruski in BNNR are 15.67; 14.9; 8.1 and 6.8 ton/ha. The database of invasive plant distribution and potential spreading will be used to monitor strategies and invasive weeds management in BNNR.

Study on Adsorption of Methylene Blue from Aqueous Solution by Biochar Derived from Mimosa Pigra Plant

Biochar from mimosa pigra was studied to remove methylene blue (MB) from aqueous solution. The properties of biochars were determined using Fourier Transform Infrared, scanning electron microscope, and Brunauer–Emmett–Teller. The biochar achieved the yield of 24.62 % at 500 oC pyrolysis. The specific surface area of ​​the biochar is 285.53 m2/g, the total pore size is 0.153 cm3/g and the ash content is 2.79%. The optimal dose of removing MB of the biochar is 5 g/L and the optimal pH is 2 - 10. MB removal reached over 80% in the first 30 min, followed by a stable period of 120 to 360 min reaching over 90% of removal. Maximum adsorption capacity reached 20.18 mg/g at 25 oC. MB adsorption data is suitable for kinetic models in order: Avrami > Elovich > PSO > PFO. The adsorption process may comprise physical and chemical adsorption andmultiple stages.

Mimosa pigra (giant sensitive plant).

M. pigra is a small prickly shrub that infests wetlands and is also an agricultural weed in rice fields in many parts of the old world tropics. In natural wetlands the shrub alters open grasslands into dense thorny thickets and negatively impacts on native biodiversity. It is regarded as one of the worst alien invasive weeds of wetlands of tropical Africa, Asia and Australia, and the cost of control is often high.

Screening and Bioguided Fractionation of Mimosa pigra L. Bee Pollen with Antioxidant and Anti-Tyrosinase Activities

Bee pollen, one of the economic bee products, is widely known as a nutritional food with many bioactivities that depend on many such factors as bee species, plant source and biogeography. For this study, bee pollen was collected from Apis mellifera, harvested from the flowers of mimosa (Mimosa pigra L.) in the Chiang Mai province, Thailand. The sample was extracted in methanol (MeOH) and then sequentially partitioned with hexane, dichloromethane (DCM) and MeOH in order to isolate compounds depending on their polarities. The obtained extracts were then tested for their antioxidant and anti-tyrosinase activities through 1,1-diphyenyl-2-picrylhydrazyl (DPPH) assay and for/through inhibition of mushroom tyrosinase extract, respectively. The DCM partitioned extract of mimosa flower bee pollen (DCMMBP) provided the highest antioxidant activity, with an effective concentration at 50% (EC50) of 192.1 μg/mL, and was further fractionated by silica gel 60 column chromatography and Sephadex LH20 size exclusion chromatography. All fractions were tested for their antioxidant activity and analyzed for the chemical structure through nuclear magnetic resonance (NMR). The most active fraction (EC50 of 121.3 μg/mL) was a mixture of compounds, but the isolated flavonoid, naringenin, had a negligible antioxidant activity. In contrast, all three partitioned extracts and pooled fractions after silica gel 60 column chromatography provided no anti-tyrosinase activity (IC50 of > 500 μg/mL) and a very low percentage of tyrosinase inhibition (0–2.99 ± 3.18%), compared to kojic acid (IC50 of 8.58 μg/mL and tyrosinase inhibition of 74.2 ± 1.25%).