Metabolomics study on the main volatile components of Thai colored rice cultivars from different agricultural locations

This study investigated the main volatile components in ten Thai colored rice varieties cultivated in two agricultural locations of Thailand (Central and Northern region) using a static headspace GC-MS metabolomics approach. The results indicated that volatolomics could successfully differentiate between the geographical origins of the same rice variety grown in regions within the same country. The volatile profiles of the colored rice obtained from the two locations were clearly different, with three volatile compounds isolated as key aroma producers in each area. Primary volatile compounds upregulated in colored rice varieties grown in Northern Thailand included undecanoic acid, 10-methyl-methyl ester; methyl 8-methyl-nonanoate; and pyrimidine, 4-methyl. Hexadecanoic acid, methyl ester; methyl 9-cis,11-trans-octadecadienoate; and 10-octadecenoic acid methyl ester were upregulated in the rice samples grown in Central Thailand. The environmental factors that could affect colored rice aroma at the agricultural sites included temperature, downward surface shortwave radiation, and vapor pressure deficit.

A taxonomic revision of Garcinia section Xanthochymus (Clusiaceae) in Thailand

Garcinia section Xanthochymus (Clusiaceae) is revised for Thailand with four native species, i.e., G. dulcis, G. nervosa, G. prainiana, and G. xanthochymus. All species are described with updated morphological descriptions, illustrations, and an identification key, together with notes on distributions, distribution maps, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses, and specimens examined. Four taxa, G. andamanica, G. andamanica var. pubescens, G. cambodgiensis and G. vilersiana, are synonymized under G. dulcis, and two taxa, G. nervosa var. pubescens and G. spectabilis, are newly synonymized under G. nervosa. Nine names are lectotypified: G. dulcis and its associated synonyms (G. cambodgiensis and G. vilersiana), G. nervosa and its associated synonyms (G. andersonii, G. nervosa var. pubescens, and G. spectabilis), G. prainiana, and G. xanthochymus. All species have a conservation assessment of Least Concern (LC). The fruits of all species are edible and have a sour or sweet-sour taste.

Morphology, Taxonomy, Anatomy, and Palynology of the Opium Poppy (Papaver somniferum L.) Cultivation in Northern Thailand

In this paper, we present the morphology, taxonomy, anatomy, and palynology of Papaver somniferum. A detailed morphological description and illustrations of the species are provided, along with information about the identification, distribution, cultivation areas, habitats, pollinators, specimens examined, growing periods, phenology, etymology, vernacular name, and uses. The species can be characterized as a glabrous and glaucous herb with unlobed or pinnately lobed leaves, and an amplexicaul base; variations in color and morphological characteristics of petals; and white filaments, occasionally purple with a white basal part, broadened at the apical part. Two rings of discontinuous and widely spaced collateral vascular bundles are recognized in the transverse section of the stems. The shape of epidermal cells on the adaxial surface is polygonal, while that on the abaxial surface is polygonal or irregular. The anticlinal cell walls of the epidermal cells on the adaxial surface are straight or slightly curved, while those on the abaxial surface are straight, slightly curved, sinuate, or strongly sinuate. The stomata are anomocytic and are confined to the lower epidermis. The stomatal density is 54-199/mm² (with a mean of 89.29 ± 24.97). The mesophyll is not distinctly differentiated into palisade and spongy regions. Laticifers are found in the phloem areas of the stems and leaves. The pollen grains can be spheroidal or prolate spheroidal in shape, sometimes oblate spheroidal [polar axis (P) diameter/equatorial axis (E) diameter ratio = 0.99-1.12 (with a mean of 1.03 ± 0.03)]. The pollen aperture is tricolpate and the exine sculpturing is microechinate.

Morphology, Taxonomy, Culm Internode and Leaf Anatomy, and Palynology of the Giant Reed (Arundo donax L.), Poaceae, Growing in Thailand

In this paper, we present the morphology, taxonomy, anatomy, and palynology of Arundo donax. A detailed morphological description and illustrations of the species are provided, along with information about the identification, distribution, the specimens examined, habitat and ecology, the International Union for Conservation of Nature (IUCN) conservation assessment, phenology, etymology, vernacular name, and uses. The species can be distinguished by its large, tall rhizomatous perennial reed; cauline leaves; an open, large, plumose panicle inflorescence; subequal glumes as long as the spikelets; glabrous rachilla; all bisexual florets; and a lemma with a straight awn and with long white hairs outside below the middle part. In this study, two names were lectotypified: Arundo bifaria and A. bengalensis, which are synonyms of A. donax. The culm internodes in the transverse section have numerous vascular bundles scattered in the ground tissue, and the parenchyma cells have significantly lignified cell walls. Vascular bundles are composed of phloem and xylem and are enclosed in a continuous sclerenchymatous bundle sheath. The chloroplasts in the transverse section of the leaf blades are found only in the mesophyll cells but are absent in the bundle sheath cells, which indicates that it is a C3 grass. The leaves have stomata on both surfaces and are confined to the intercostal zones. The stomata are typically paracytic, with two lateral subsidiary cells placed parallel to the guard cells. The stomatal density is higher on the abaxial surface [450-839/mm² (606.83 ± 72.71)] relative to the adaxial surface [286-587/mm² (441.27 ± 50.72)]. The pollen grains are spheroidal or subspheroidal [polar axis length/equatorial axis length ratio (P/E ratio) = 0.89-1.16 (1.02 ± 0.07)] with a single pore surrounded by a faint annulus, and the exine sculpturing is granular.

Assessing the Cooling and Air Pollution Tolerance among Urban Tree Species in a Tropical Climate

We present the results of classifying plants at species level that can tolerate air pollution, provide cooling, and simultaneously survive and thrive in urban environments. For this purpose, we estimated the air pollution tolerance index (APTI) and anticipated performance index (API) of several species growing in a park located in central Bangkok, Thailand. The cooling effect was quantified by calculating the reduction in soil and air temperatures. Melaleuca quinquenervia (Cav.) S.T. Blake, Albizia saman (Jacq.) Merr., Chukrasia tabularis A. Juss. had the highest API score and were able to substantially reduce the temperature and were in a group of highly recommended species which also included other species like A. saman, C. tabularis, Tabebuia rosea (Bertol.) Bertero ex A. DC., Dalbergia cochinchinensis Pierre etc. Species from both evergreen and deciduous habitat were able to provide ambient cooling but were vulnerable to air pollution and included Elaeocarpus grandifloras Sm. and Bauhinia purpurea L. However, there were other species which had a high air pollution tolerance but failed to provide adequate cooling, such as Hopea odorata Roxb. and Millingtonia hortensis L.f. The results would be of interest to urban greenspace landscapers in such climates while selecting suitable species that can provide multiple ecosystem services ranging from air pollution tolerance to temperature reduction without reducing plant vitality.

Variations in mitragynine content in the naturally growing Kratom (Mitragyna speciosa) population of Thailand

We analyzed the content of mitragynine (MG) found in kratom leaves (Mitragyna speciosa) and the influence of different environmental conditions (air and soil variables) on the yield in various regions of Thailand. The content of MG in kratom leaves ranged from 7.5 - 26.6 mg g^-1 of dry leaf weight. Canonical correspondence analysis showed that the most significant environmental variables affecting the MG content among the various regions were light intensity, relative humidity, soil volumetric water content (VW), soil pH, and calcium. This study is a first step towards providing information about environmental conditions suitable to maximize the quality and quantity of bioactive alkaloids in kratom. Future studies should focus on leaf collection and the post-harvest processes in order to assure the desired alkaloidal content in finished products, when produced under suitable environmental conditions identified in this study.

Monetary evaluation of supporting ecosystem services as a habitat provider for birds in Thailand urban park

Abstract. Yarnvudhi A, Leksungnoen N, Siri S, Ponpithuk Y, Sukmasuang R, Duengkae P, Pongcharoen C, Sutummawong N, Marod D, Wachrinrat C, Premashthira A, Tor-ngern P, Poungcharean S, Hermuk S, Kachina P. 2022. Monetary evaluation of supporting ecosystem services as a habitat provider for birds in Thailand urban park. Biodiversitas 23: 4747-4758. Supporting services are important services to maintain ecosystems by providing habitats for organisms and genetic diversity. In this study, the monetary value of supporting services for bird habitats in urban parks was evaluated based on the price for nursing each bird species and market value. Bird diversity was conducted using point count observation. We found total of 53 bird species, 27 families and 8 orders in the park. Total monetary benefit for bird habitats in this park was estimated to be around USD60,354.12 per individual bird with an average value of USD1,138.76 per bird per species. The top three species with the highest monetary value were the Painted Stork (Mycteria leucocephala), Asian Openbill (Anastomus oscitans), and Chinese Pond Heron (Ardeola bacchus). The species diversity index of the bird community (H') was 2.73 and the most abundant bird species were Eastern Spotted Dove (Spilopelia chinensis), Eurasian tree sparrow (Passer montanus), Eastern jungle crow (Corvus levaillantii), Oriental magpie robin (Copsychus saularis), and Coppersmith Barbet (Psilopogon haemacephalus). Among 4 microhabitats, birds were found the most in the trees, followed by lawn, grassland, and wetland areas. The small urban parks should be designed with diverse microhabitats to provide various ecological functions to attract and ensure adequate resources for organisms.

Comparison of water-use characteristics of tropical tree saplings with implications for forest restoration

Tropical forests are experiencing reduced productivity and will need restoration with suitable species. Knowledge of species-specific responses to changing environments during early stage can help identify the appropriate species for sustainable planting. Hence, we investigated the variability in whole-tree canopy conductance and transpiration (Gt and EL) in potted saplings of common urban species in Thailand, viz., Pterocarpus indicus, Lagerstroemia speciosa, and Swietenia macrophylla, across wet and dry seasons in 2017-2018. Using a Bayesian modeling framework, Gt and EL were estimated from sap flux density, informed by the soil, atmospheric and tree measurements. Subsequently, we evaluated their variations with changing vapor pressure deficit (VPD) and soil moisture across timescales and season. We found that Gt and EL were higher and highly variable in L. speciosa across seasons than S. macrophylla and P. indicus. Our results implied that water-use in these species was sensitive to seasonal VPD. L. speciosa may be suitable under future climate variability, given its higher Gt and EL across atmospheric and soil moisture conditions. With their lower Gt and EL, P. indicus and S. macrophylla may photosynthesize throughout the year, maintaining their stomatal opening even under high VPD. These findings benefit reforestation and reclamation programs of degraded lands.

Germination and salinity tolerance of seeds of sixteen Fabaceae species in Thailand for reclamation of salt-affected lands

Abstract. Ku-Or Y, Leksungnoen N, Onwinom D, Doomnil P. 2020. Germination and salinity tolerance of seeds of sixteen Fabaceae species in Thailand for reclamation of salt-affected lands. Biodiversitas 21: 2188-2200. Over the years, areas affected by salinity have increased dramatically in Thailand, resulting in an urgent need for reclamation of salt-affected areas using salinity tolerant plant species. In this context, seed germination is an important process in plant reproduction and dispersion. This research aimed to study the ability of 16 fabaceous species to germinate and tolerate salt concentrations of at 6 different levels (concentration of sodium chloride solution, i.e., 0, 8, 16, 24, 32, and 40 dS m-1). The germination test was conducted daily for 30 days, and parameters such as germination percentage, germination speed, and germination synchrony were calculated. The electrical conductivity (EC50) was used to compare the salt-tolerant ability among the 16 species. Our results showed that the germination percentage, germination speed, and germination synchrony of all species decreased with an increase in salinity concentration. The mean germination time increased from 2-4 days under 0 dS m-1 to 4-10 days under 16 dS m-1, indicating that the seeds germinated at a slower rate as the salinity levels increased. Seed germination percentage was more than 80% across all the species at salinity levels between 0 to 16 dS m-1. Sesbania grandiflora, Senna siamea, and Dalbergia cochinchinensis had a high EC50 value of 33.56, 32.93, and 30.83 dS m-1 respectively, suggesting that these species were the three most salt-tolerant species in this study. As such, the establishment of these species in salt-affected areas should be studied further in order to reclaim such affected lands.

Investigating carbon dioxide absorption by urban trees in a new park of Bangkok, Thailand

Background

Trees remove atmospheric carbon dioxide through photosynthesis, hereafter CO₂ absorption (A). Despite growing urban green areas, only a few studies have quantified A of urban trees and assessed their dynamical changes with varying atmospheric conditions. Hence, we investigated A in nine dominant tree species in a new park of Bangkok.

Results

Results revealed that A of two tree species (Millingtonia hortensis and Afzelia xylocarpa) significantly increased with vapor pressure deficit (VPD) until it reached a maximum and declined when VPD decreased, with no seasonal difference. Five of them (Dalbergia cochinchinensis, Tabebuia rosea, Lagerstroemia floribunda, Dipterocarpus alatus and Bauhinia purpurea) exhibited different response patterns of A to VPD between wet and dry seasons. In contrast, the A of two tree species (Samanea saman and Homalium tomentosum) did not respond to changing VPD in either season.

Conclusions

Comparing planting scenarios of insensitive (i.e. no response to VPD) versus sensitive (i.e. significant response to VPD) species, we found that planting a mixture of sensitive and insensitive tree species would improve the park’s capacity of A across seasons, allowing climate change adaptation to adverse environmental impacts such as droughts and the urban heat island effects, and would increase biodiversity. Additionally, planting insensitive tree species would significantly increase the capacity of the park for CO₂ mitigation. These findings are useful for those who design parks and expand urban green areas to fully benefit ecosystem services from trees.