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DocumentThe interaction between particulate matter (PM) adsorption and leaf gas exchange characteristics of urban trees exposed to fly ash
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.Because of their vast surface distribution, external particle reactivity, and leaf characteristics, urban trees can contribute as biofilters, reducing PM pollution. Leaves of trees permit PM to be accumulated, depending on their leaf traits. The impacts of several leaf characteristics on PM accumulation capabilities, such as surface roughness and leaf morphology, have been studied. The change in relative humidity (RH) caused by leaf gas exchanges of urban trees also can be highly related to the removal efficiency of PM because the hygroscopic growth of particle is closely related to PM deposition. Nevertheless, the impacts of leaf gas exchange parameters including stomatal conductance and transpiration rate on PM deposition ability still remain unidentified. The effects of PM pollution on urban plants’ photosynthesis are also not well understood. In this study, we analyzed the correlation between PM accumulation and photosynthesis (Pn), stomatal conductance (gs) and transpiration (Tr) of all the tested urban trees under approximately 300 μg/m3 of fly ash emitted condition and evaluated the increased effect of leaf gas exchange parameters on PM deposition. We also studied whether the inhibiting impacts on the ability of leaf gas exchange is occurred by the blockage and closure of the stomata by using scanning electron microscopy (SEM). The purpose of our research was to better understand the interaction between particulate matter (PM) adsorption and leaf gas exchange characteristics of urban trees. Furthermore, the findings of this study can be used to provide scientific data about the suitability of tree species for urban forests. Keywords: Research, Climate change, Sustainable forest management ID: 3623026 -
DocumentHigh-biobased-content UV-curable oligomers derived from tung oil and citric acid: Microwave-assisted synthesis and properties
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.Ultraviolet (UV)-curing technique has been widely applied in modern industrial areas such as coatings, inks, and adhesives due to their “5E” advantages, i.e. efficient, energy saving, enabling, economical, and eco-friendly. However, due to the dramatic fluctuation of oil prices, greenhouse effect from CO2 emission, and serious environmental problems, much efforts have been devoted into the preparation of UV-curable materials from renewable resources such as carbohydrates, plant oils, and rosins.
In this study, two novel UV-curable oligomers (TMCG1 and TMCG2) from tung oil and citric acid were synthesized via microwave technology and confirmed by FT-IR,1H NMR, and 13C NMR. The total reaction time was only 30 min, and the obtained oligomers showed high biobased contents (over 60%). Furthermore, a series of UV-curable coatings were constructed by copolymerizing the oligomers with a biobased reactive diluent (GA) from guaiacol. The resulting UV-cured materials achieved both high biobased content and high performance. For instance, the cured TMCG1 film with 10% of GA showed a biobased content of 72.4%, tensile strength of 16.6 MPa, glass transition temperature of 74.1 oC, maximum thermal degradation temperature of 437.2 oC, adhesion of 2 grade, pencil harness of 2H, and flexibility of 2 mm.
In general, the biobased UV-curable coatings show great potential to be applied in the fields of coatings like wood coatings, and the combination of bioresources, microwave technology, and UV-curing technology indicated in this work could provide a “green + green + green” solution for the coating industry. Keywords: Agriculture, Economic Development, Education, Research, Innovation ID: 3483375 -
ArticleTaxonomic value of leaf epidermal markers in discriminating medicinal tree species of Apocynaceae Juss in Nigeria 2022
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No results found.Apocynaceae is a useful family comprising of trees notable for different medicinal remedies. Consequent to their importance vis-à-vis scarcity in the forest, they are being sold in various Nigerian markets by herb sellers mostly in sterile and fragmentary forms. Hence, the medicinal plants are subjected to adulteration and substitution. Identification of the plants by users is done via floristic markers, which are not readily available for such purpose. It becomes pertinent to carry out the taxonomic revision of these trees to provide additional markers that will contribute to their effective identification for correct use. Various documentations have been made on members of apocynaceae and are properly placed on their respective taxa using epidermal traits. However, such information is scarce for Alstonia boonei, Holarrhena floribunda, Rauvolfia vomitoria, Thevetia nerifolia and Vocanga africana. This study therefore aimed at providing epidermal taxonomic markers that could be employed in delimiting the species as an alternative when the fruit or floral parts are wanting. Leaf epidermises of five species of apocynaceae representing 5 genera were studied under a biological microscope with a camera attachment. Data obtained were statistically analyzed. The epidermal cell was penta or hexagonal in A. boonei and V. africana. The stomatal length varied from 20.88 µm (R. vomitoria) to 25.92 µm (T. nerifolia) and 18.96 µm (R. vomitoria) to 29.28 µm (V. africana) on the abaxial and adaxial layers respectively. All the epidermal characters on the adaxial layer were significantly different (p<0.05) among the species. Anticlinal walls were sinuated in H. floribunda and T. nerifolia while in R. vomitoria, it was straight to wavy. V. africana and A. boonei anticlinal walls were straight. This study represents the first account of epidermal characterization of the members of apocynaceae in Nigeria and is of taxonomic importance in setting boundaries among the species. Keywords: Human health and well-being, Biodiversity conservation, Genetic resources ID: 3486776
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