Wei Ta Fang

Indole-3-acetic acid-producing yeasts in the phyllosphere of the carnivorous plant Drosera indica L

Yeasts are widely distributed in nature and exist in association with other microorganisms as normal inhabitants of soil, vegetation, and aqueous environments. In this study, 12 yeast strains were enriched and isolated from leaf samples of the carnivorous plant Drosera indica L., which is currently threatened because of restricted habitats and use in herbal industries. According to similarities in large subunit and small subunit ribosomal RNA gene sequences, we identified 2 yeast species in 2 genera of the phylum Ascomycota, and 5 yeast species in 5 genera of the phylum Basidiomycota. All of the isolated yeasts produced indole-3-acetic acid (IAA) when cultivated in YPD broth supplemented with 0.1% L-tryptophan. Growth conditions, such as the pH and temperature of the medium, influenced yeast IAA production. Our results also suggested the existence of a tryptophan-independent IAA biosynthetic pathway. We evaluated the effects of various concentrations of exogenous IAA on yeast growth and observed that IAA produced by wild yeasts modifies auxin-inducible gene expression in Arabidopsis. Our data suggest that yeasts can promote plant growth and support ongoing prospecting of yeast strains for inclusion into biofertilizer for sustainable agriculture.

Plant growth-promoting traits of yeasts isolated from the phyllosphere and rhizosphere of Drosera spatulata Lab.

Microorganisms can promote plant growth through direct and indirect mechanisms. Compared with the use of bacteria and mycorrhizal fungi, the use of yeasts as plant growth-promoting (PGP) agents has not been extensively investigated. In this study, yeast isolates from the phyllosphere and rhizosphere of the medicinally important plant Drosera spatulata Lab. were assessed for their PGP traits. All isolates were tested for indole-3-acetic acid-, ammonia-, and polyamine-producing abilities, calcium phosphate and zinc oxide solubilizing ability, and catalase activity. Furthermore, the activities of siderophore, 1-aminocyclopropane-1-carboxylate deaminase, and fungal cell wall-degrading enzymes were assessed. The antagonistic action of yeasts against pathogenic Glomerella cingulata was evaluated. The cocultivation of Nicotiana benthamiana with yeast isolates enhanced plant growth, indicating a potential yeast-plant interaction. Our study results highlight the potential use of yeasts as plant biofertilizers under controlled and field conditions.

A National Investigation of Teachers' Environmental Literacy as a Reference for Promoting Environmental Education in Taiwan.

Taiwans government enacted the Environmental Education Act in June 2011. In the beginning of the implementation of the Act, a national assessment of schoolteachers’ environmental literacy was performed in order to establish the baseline for evaluating the effectiveness of environmental education policy. This large-scale assessment involved a large sample size of in-service teachers across schools at all levels and regions in Taiwan using the stratified random sampling method. Data showed that the teachers have satisfactory levels of environmental knowledge and attitudes, but presented low degrees of environmental action. Differing from previous research results, elementary teachers performed better than high school teachers on this assessment, which may be attributed to their teacher training experiences. Results from this study may provide implications for teacher professional development programs and school environmental education policy.

Analysis of trends in water quality: constructed wetlands in metropolitan Taipei.

Meandering through the most densely populated metropolitan areas of Taipei, Taiwan, the Danshui River and its tributaries have undergone the construction of 14 wetlands since 2004, as a means to improve water quality. This study was conducted to examine the functional capabilities associated with treating non-point source pollution through these riparian wetlands. Trend analysis was used to differentiate dissolved oxygen, biochemical oxygen demand, suspended solids, ammonia, and Escherichia coli, among 13 sampling sites using both functions of a Mann-Kendall test and a seasonal Mann-Kendall test. The results show that water quality in Taipei metropolitan rivers has been improving since increasing the number of constructed wetlands and connecting households to the public sewage system. The concentration of pollutants such as those influencing biochemical oxygen demand have gradually declined in drought seasons because riparian wetlands contribute a base flow to dilute riverine pollutants. This paper indicates that the creation of treatment systems influences dissolved oxygen conditions at the municipal scale, suggesting that constructed wetlands could stabilize water quality during extreme hydrological events and improve water quality particularly in times of drought.

Distribution of heavy metals in the sediments of agricultural fields adjacent to urban areas in Central Taiwan

In 2002, the Environmental Protection Administration of Taiwan began a detailed survey of heavy metals in soils, to determine the scope of the contaminated lands in the Changhua County’s agricultural fields. It was found that agricultural lands have been seriously polluted with Cr, Hg, Cu, Ni, and Zn, due to industrial wastewaters. This study, characterized the processes associated with heavy metal pollution by analyzing heavy metal contents in sediments within two periods, 2002 and 2010. This study employed geostatistical and multivariate statistics to obtain spatio-temporal variations of heavy metal pollution in paddy fields. The results indicate that, changes in industrial types have been altered the characteristics of pollutions, such as reducing the number of plants in industries (i.e., electroplating, surface treatments, metal works, chemicals, papermaking, etc.). Their wastewaters contained a large number of Ni, making the pollution composition of driven factors have been changed that can be indicated in this study. Pollution distribution and irrigation systems are positively correlated and concentrations of Cr, Cu, Ni, and Zn were inversely proportional to the scale of irrigation channels.

Physical Outdoor Activity versus Indoor Activity: Their Influence on Environmental Behaviors

There are strong evidences linking physical outdoor activity and health benefits; however, little is known about the impact on environmental behaviors. Thus, this study aims to close this gap by investigating the influence of physical outdoor activity on environmental behaviors. A total of 416 surveys were distributed to students in eight public primary schools located near the Hsinchu Science and Industrial Park in Taiwan. Findings from the analysis revealed that subjective norms had a more influential effect on environmental behaviors for participants who engaged in physical activity at outdoor parks. In contrast, descriptive norms had a direct predictive impact on environmental behaviors for participants whose main physical activity venue was at the indoor after-school centers. Research results also highlighted attitude as the strongest predictive variable influence on environmental behaviors for children who engaged in physical indoor and outdoor activities.

Creating Pondscapes for Avian Communities: An Artificial Neural Network Experience Beyond Urban Regions

Farm ponds are unique geographic features of the Taoyuan Tableland. Besides irrigation, they provide refuges for wintering birds. The issue at hand is that these features are disappearing, and this brings with it the loss of this refuge function. It is ecologically significant because one-fifth of all the bird species in Taiwan find a home on these ponds. This study aims at characterizing the diversity of bird species associated with these ponds, whose likelihood of survival was assessed along the gradient of land development intensities. Such characterization helps establish the decision criteria needed for designating certain ponds for habitat preservation and developing their protection strategies. A holistic model was developed by incorporating logistic regression with error back-propagation into the paradigm of artificial neural networks (ANN). The model considers pond shape, size, neighboring farmlands, and developed areas when calculating parameters pertaining to their respective and interactive influences on avian diversity, among them the Shannon–Wiener diversity index (H′). Results indicate that ponds with a regular shape or ones of larger size possess a strong positive correlation with H′. Farm ponds adjacent to farmland benefited the diversity of waterside birds. On the other hand, urban development was shown to cause a reduction of farmland and pond numbers, which in turn reduced the diversity of waterside birds. By running the ANN model with four neurons, the resulting H′ index shows a good-fit prediction of bird diversity against pond size, shape, neighboring farmlands, and neighboring developed areas with a correlation coefficient (r) of 0.72, in contrast to the results from a linear regression model (r < 0.28).

Simple Patchy-Based Simulators Used to Explore Pondscape Systematic Dynamics

Thousands of farm ponds disappeared on the tableland in Taoyuan County, Taiwan since 1920s. The number of farm ponds that have disappeared is 1,895 (37%), 2,667 ponds remain (52%), and only 537 (11%) new ponds were created within a 757 km2 area in Taoyuan, Taiwan between 1926 and 1960. In this study, a geographic information system (GIS) and logistic stepwise regression model were used to detect pond-loss rates and to understand the driving forces behind pondscape changes. The logistic stepwise regression model was used to develop a series of relationships between pondscapes affected by intrinsic driving forces (patch size, perimeter, and patch shape) and external driving forces (distance from the edge of the ponds to the edges of roads, rivers, and canals). The authors concluded that the loss of ponds was caused by pond intrinsic factors, such as pond perimeter; a large perimeter increases the chances of pond loss, but also increases the possibility of creating new ponds. However, a large perimeter is closely associated with circular shapes (lower value of the mean pond-patch fractal dimension [MPFD]), which characterize the majority of newly created ponds. The method used in this study might be helpful to those seeking to protect this unique landscape by enabling the monitoring of patch-loss problems by using simple patchy-based simulators.

The effect of developing a tunnel across a highway on the water quality in an upstream reservoir watershed area- a case study of the hsuehshan tunnel in Taiwan

Cities in Taiwan are so dependent on reservoir water that preservation of the upstream reservoir watershed has become a significant public concern. However, due to the high-density development of land, resulting in rapid urban expansion, the construction of tunnels and elevated highways across reservoirs to better utilize the surrounding land has become a global trend. Based on data from long-term observation of the reservoir, this study verifies the difference in water quality before and after the highway construction. The results indicate that the total phosphorus (TP) increased on average 14 μg/L to 36.5 μg/L per annum, and the water quality is expected to require 10 years to recover. During the highway development, the average TP was more than twice the normal level. During summer, the TP level increases 3.1-fold due to rainfall. As indicated by the results, the large-scale land development will harm the long-term preservation of the reservoir’s water quality, and therefore should be avoided.

Dynamic behavior of stormwater quality parameters in South Texas

To control water impairment in urban stormwater, it is important to evaluate changing patterns of water quality parameters in stormwater runoff. Thus, the authors performed a series of experiments to investigate the dynamics of common water parameters during storm events in semi-arid areas, with multiple samples collected and analyzed in field stormwater applications. At this field monitoring site within McAuliffe Park, McAllen, Texas, in the United States, a storm event increased the concentrations of Escherichia coli (E. coli), but this event represented a decreasing trend over the entire event period. Besides, peak intensity of different pollutants in the stormwater runoff occurred at different times other than at any peak flows, representing a complexity of the temporal and spatial measurements. Multi-sample perevent approaches recommended based on the complexity of the hydrograph and different peak intensity times of pollutants. In addition, high bacteria and total suspended solids (TSS) concentrations in the initial stage of the storm event should be considered when designing Best Management Practices (BMPs) and Low Impact Developments (LIDs). New strategies and solutions for addressing ecohydrological challenges should be proposed to avoid collateral damages to their both common wealth in ecosystems and human well-beings.