Laboratory and field measurements of water relations, photosynthetic parameters, and hydration traits in macrolichens in a tropical lower montane rainforest in Thailand.

Ecophysiological studies of lichens in tropical Asia are rare, and additional studies can increase the understanding of lichen life in this region. The main aim of this study was to observe the relationships between water availability and photosynthetic parameters, as well as hydration trait parameters, in macrolichens during the rainy and dry seasons in a tropical forest. A total of 11 lichen species growing in a lower montane rainforest in Thailand were collected and studied. The results clearly showed that the specific thallus mass (STM), net photosynthetic rate (Pn), the potential quantum yield of primary photochemistry (Fv/Fm), chlorophyll content, and carotenoid content of almost all lichens were lower in the dry season than in the rainy season. Field measurements in the dry season revealed that only the foliose chlorolichen Parmotrema tinctorum was metabolically active and exhibited slight carbon assimilation. In the rainy season, all lichens started their photosynthesis in the early morning, reached maximal values, declined, and ceased when the thalli desiccated. The photosynthetically active period of the lichens was approximately 2-3 h in the morning, and the activities of the cyanolichens ended approximately 30 min after the chlorolichens. The hydration trait parameters, including the STM, maximal water content (WCmax), and water holding capacity (WHC), were greater in the cyanolichens. In addition, the maximal Pn (Pnmax) and optimal water content (WCopt) for Pn were also greater in the cyanolichens, but the maximal Fv/Fm (Fv/Fmmax) was lower. The cyanolichens compensated for their inability to use humid air to restore photosynthesis by having higher water content and storage, higher photosynthetic rates, and longer photosynthetically active periods. This study provides additional insights into lichen ecophysiology in tropical forests that can be useful for lichen conservation.

Bark, soil and lichens are effective indicators of dust from limestone industries in Thailand.

Cement production, quarrying and stone crushing are major emission sources of alkaline dust that can affect human health and vegetation. The main objectives of this study were to evaluate the potential of using bark pH, soil pH and lichen community for indicating alkaline dust pollution. Twelve polluted sites were in a limestone industrial area. Bark pH and the lichen community were observed on Alstonia scholaris trees, and soil pH was obtained from topsoil samples. The bark pH at all polluted sites was significantly higher (5.5 to 7.3) than that at the unpolluted site (4.3). Among the polluted sites, the highest bark pH value was observed at the nearest site to the center of the industrial area, while the lowest value was discovered at the farthest site. Bark pH showed a strongly negative correlation with the distance from the center. Soil pH at the unpolluted site (6.3) was also significantly lower than that at the polluted sites (7.6 to 8.1), except at the farthest site (6.5). The soil pH also tended to increase closer to the center. Seven lichen species were observed on the trunks of investigated trees in all polluted sites and were observed only at sites more than 4.7 km away from the center, where bark pH ranged from 5.5 to 6.3. The extent of dust impact on vegetation seemed to be within 6-7 km from the center. The results of this study confirm the potential of the bark pH of A. scholaris, soil pH and lichen community as long-term indicators of alkaline dust pollution.

Lichen biomonitoring of seasonal outdoor air quality at schools in an industrial city in Thailand.

Poor air quality in school environments causes adverse health effects in children and decreases their academic performance. The main objective of this study was to use lichens as a biomonitoring tool for assessing outdoor air quality at schools in the industrial area of Laem Chabang municipality in Thailand. Thalli of the lichen Parmotrema tinctorum were transplanted from an unpolluted area to nine schools in the industrial area and to a control site. The lichens were exposed for four periods in the dry, hot, early rainy, and late rainy seasons, for 90 days each. The concentrations of 14 elements, including As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Ti, V, and Zn, were determined using inductively coupled plasma‒mass spectrometry (ICP‒MS), and 8 physiological parameters were measured. The concentrations of all 14 investigated elements were clearly higher at the schools than at the control site. The contamination factors (CFs) suggested that 9 out of the 14 elements, including As, Cd, Co, Cr, Cu, Mo, Pb, Sb, and Ti, heavily contaminated the school environments, especially Pb, the concentration of which was 3 to 11 times higher than at the control site. The most polluted time was the hot season as evidenced by the investigated elements, and the least polluted time was the late rainy season. The pollution load indices (PLIs) demonstrated that schools in the inner and middle zones clearly had higher pollution loads than the schools in the outer zone during the rainy seasons, while the hot and dry seasons showed similar pollution levels in all zones. The vitality indices (VIs) showed that the lower lichen vitalities at most schools were observed during the dry season and at the schools in the inner and middle zones. Accordingly, the air performance indices (APIs) revealed that poorer air quality at most schools was found during the dry season and at the schools in the inner and middle zones. This study clearly showed that the transplanted lichen P. tinctorum was an effective bioindicator of air quality in school environments. The results illustrated that all studied schools were contaminated by air pollutants; therefore, improving air quality at the schools is crucial and should be an urgent issue for maintaining good health and may benefit children's academic achievements and careers in the long run.

Influence of washing thalli on element concentrations of the epiphytic and epilithic lichen Parmotrema tinctorum in the tropic.

To enhance the reliability of active biomonitoring of air pollution using lichens, we tested how a water-washing procedure influences element concentrations in lichens growing on bark and rock substrates. Thalli of the lichen Parmotrema tinctorum were collected from tree bark and sandstones from a relatively clean air site in Khao Yai National Park, Thailand. After dry cleaning, each thallus was divided equally: the first part was directly used for element analysis, and the second part was washed with deionized water before it was sent for element analysis. The concentrations of 13 elements, including Al, As, Ca, Cu, Fe, K, Mg, Mn, Se, Sr, Ti, V, and Zn, were determined using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the washing procedure substantially decreased the amounts of most elements in the lichens; after washing, concentrations of the elements in the epiphytic thalli showed decreases ranging from 17 to 81% (54% on average), and those in the epilithic thalli showed decreases ranging from 10 to 27% (18% on average). The coefficient of variation (CV) was also reduced for most elements, especially for those in the epiphytic thalli, indicating that washing could produce more homogeneous samples. All elements from the unwashed samples had higher contents in the epiphytic thalli than in the epilithic thalli, but the element contents were higher in the epilithic thalli after washing. Most elements in the washed epiphytic and epilithic thalli were not comparable, indicating that the washing procedure did not produce the same order of magnitude of element contents in the epiphytic and epilithic thalli. Based on the results of this study, we recommend washing pre-exposed lichen samples for more reliable results in active biomonitoring studies of air pollution.

Evaluation of six regions for their potential as DNA barcodes in epiphyllous liverworts from Thailand.

PREMISE OF THE STUDY: Studies on the diversity of epiphyllous bryophytes have been limited because of minute and incomplete specimens and a lack of taxonomic expertise. The recent development of the DNA barcoding approach has allowed taxon identification and species discovery of many obscure groups of organisms. METHODS: With DNA extractions from 99 samples of 16 species, we compared the efficiencies of six DNA markers (rbcL, matK, trnL-F, psbA, ITS1, and ITS2) in their ability to amplify, using a standard set of primers, as well as their discriminatory power, using distance-based and tree-based approaches with nucleotide data. RESULTS: The amplification success was relatively high (70-90%) with all of the markers, except for matK, which yielded no success. The barcoding gap, as calculated from the difference between inter- and intraspecific genetic distances, was the highest in ITS2, whereas the highest numbers of monophyletic groups were found with ITS2 and rbcL. DISCUSSION: rbcL should be used as a main barcoding marker with the addition of ITS2 for epiphyllous species. The development of DNA barcoding as a tool for quantifying species diversity will provide a rapid and reliable identification tool for epiphyllous bryophytes.

Airborne trace elements near a petrochemical industrial complex in Thailand assessed by the lichen Parmotrema tinctorum (Despr. ex Nyl.) Hale.

Several trace elements discharged by the petrochemical industry are toxic to humans and the ecosystem. In this study, we assessed airborne trace elements in the vicinity of the Map Ta Phut petrochemical industrial complex in Thailand by transplanting the lichen Parmotrema tinctorum to eight industrial, two rural, and one clean air sites between October 2013 and June 2014. After 242 days, the concentrations of As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Ti, V, and Zn in lichens at most industrial sites were higher than those at the rural and the control sites; in particular, As, Cu, Mo, Sb, V, and Zn were significantly higher than at the control site (p < 0.05). Contamination factors (CFs) indicated that Cd, Cu, Mo, and Sb, which have severe health impacts, heavily contaminated at most industrial sites. Principal component analysis (PCA) showed that most elements were associated with industry, with lesser contributions from traffic and agriculture. Based on the pollution load indexes (PLIs), two industrial sites were highly polluted, five were moderately polluted, and one had a low pollution level, whereas the pollution load at the rural sites was comparable to background levels. This study reinforces the utility of lichens as cost-effective biomonitors of airborne elements, suitable for use in developing countries, where adequate numbers of air monitoring instruments are unavailable due to financial, technical, and policy constraints.

Using phylogenetic and coalescent methods to understand the species diversity in the Cladia aggregata complex (Ascomycota, Lecanorales).

The Cladia aggregata complex is one of the phenotypically most variable groups in lichenized fungi, making species determination difficult and resulting in different classifications accepting between one to eight species. Multi-locus DNA sequence data provide an avenue to test species delimitation scenarios using genealogical and coalescent methods, employing gene and species trees. Here we tested species delimitation in the complex using molecular data of four loci (nuITS and IGS rDNA, protein-coding GAPDH and Mcm-7), including 474 newly generated sequences. Using a combination of ML and Bayesian gene tree topologies, species tree inferences, coalescent-based species delimitation, and examination of phenotypic variation we assessed the circumscription of lineages. We propose that results from our analyses support a 12 species delimitation scenario, suggesting that there is a high level of species diversity in the complex. Morphological and chemical characters often do not characterize lineages but show some degree of plasticity within at least some of the clades. However, clades can often be characterized by a combination of several phenotypical characters. In contrast to the amount of homoplasy in the morphological characters, the data set exhibits some geographical patterns with putative species having distribution patterns, such as austral, Australasian or being endemic to Australia, New Zealand or Tasmania.