Narong Wongkantrakorn

The application of herbicides in rice fields necessitates an understanding of their effects on non-target organisms, particularly cyanobacteria, which serve as primary producers in the ecosystem. This study examined the impact of commercial paraquat and butachlor formulations on the...

The excessive use of chemical fertilizers in rice cultivation has contributed to soil degradation, creating a need for sustainable biological alternatives. This study examined the functional diversity of three indigenous nostocalean cyanobacterial strains (UP1, UP2, and UP3) isolated from forest and paddy field ecosystems by comparing the effects of their cellular biomass and extracellular polymeric substances (EPS) on rice seedling growth and soil properties. Morphological observations and partial 16S rRNA sequence analysis indicated that strains UP1 and UP2 were affiliated with the genus Ahomia, whereas UP3 was placed within the genus Nostoc. Together, these results placed all three isolates within the heterocystous cyanobacterial order Nostocales. The strains were further characterized based on EPS production and its degree of polymerization. Seed germination and seedling vigor assays were conducted to select the most effective biomass and EPS treatments, which were subsequently evaluated in 21-day pot experiments. Fresh biomass from strain UP2 most effectively enhanced rice growth, whereas EPS from strain UP3 promoted root development. EPS application from strain UP3 significantly increased root elongation to 13.44 cm, while high biomass levels of UP2 increased total sugar and free amino acid contents, indicating distinct plant response patterns. Soil analyses revealed differential responses between biomass- and EPS-based applications, with biomass generally producing stronger effects. Biomass from all strains was associated with higher physical soil function index (PSFI) values (up to 1.35). In contrast, improvements in chemical soil function index (CSFI) were observed across treatments, with variable responses and relatively higher values recorded in biomass from strain UP3 (up to 1.24). These findings suggest strain- and form-dependent response patterns of nostocalean cyanobacteria with potential for enhancing rice growth and improving soil functionality under the controlled conditions.

Ramita Liamchang, Neti Ngearnpat, Narong Wongkantrakorn, Jirapa Wongsa and Kritchaya Issakul. J Ecol Environ 2025;49:. https://doi.org/10.5141/jee.25.050

Turmeric (Curcuma longa L. cv. Trang 1), a high-value cultivar known for its elevated curcuminoid and volatile oil content, holds significant potential in pharmaceutical and food applications. However, its commercial propagation is constrained by low rhizome productivity and the limitations of conventional vegetative propagation. This study aimed to improve the propagation efficiency of turmeric cv. Trang 1 by developing optimized protocols for explant sterilization, shoot proliferation, root induction, and acclimatization. Sprouted rhizome buds were sterilized and cultured on a Murashige and Skoog (MS) medium supplemented with various plant growth regulators, including cytokinins (benzyladenine [BA], thidiazuron [TDZ], and meta-topolin [mT]) and auxins (indole-3-butyric acid [IBA] and 1-naphthaleneacetic acid [NAA]). The shoot induction (4.60 ± 1.47 shoots per explant) and shoot height (2.34 ± 0.61 cm) were observed on the MS medium with 3.0 mg/L BA, while the TDZ, at 0.5 mg/L, also induced a high number of shoots (5.22 ± 0.64). When using single shoots derived from bud explants, mT at 1.5 mg/L significantly enhanced the shoot formation. For the root induction, 2.0 mg/L IBA yielded the highest number of roots (7.33 ± 1.49), while NAA was less effective. The plantlets acclimatized in a 1:1 soil and peat moss mixture showed the highest survival rate (86.67%). This improved protocol enables the efficient production of turmeric plantlets, supporting commercial deployment.

Rice (Oryza sativa L.) is a staple food for billions of people globally. Rice cultivar RD43 has been recognized for its health benefits but has faced declining productivity due to climate change. Plant tissue culture serves as a powerful tool for studying and improving rice cultivars, yet a standardized protocol for rice cv. RD43 is lacking. This study aims to establish an efficient plant tissue culture protocol for rice cv. RD43 by evaluating concentrations of plant growth regulators for callus induction, proliferation, and regeneration. Callus induction was most effective with 4.0 mg/L of 2,4-dichlorophenoxyacetic acid (2,4-D), while callus proliferation was effective with 2.0 mg/L of 2,4-D. Furthermore, 2.0 mg/L of 6-benzyladenine (BA) yielded the highest plant regeneration, achieving a 50% regeneration rate and producing 9.60 shoots per callus. These findings lay the groundwork for a robust tissue culture protocol for rice cv. RD43 as a means for advanced breeding studies and contributing to global food security amid climate change challenges.

Clausena lenis Drake, a valuable medicinal plant in the Rutaceae family, faces threats from wildlife predation, overharvesting, and climate change. In the wild, C. lenis primarily propagates through seeds; however, their rapid loss of viability poses challenges for long-term storage and germplasm conservation. Plant tissue culture offers a practical solution for both its conservation and large-scale production. This study examines seed sterilization, callus induction, shoot multiplication, and root induction protocols for C. lenis. Seeds attained a 100% sterilization rate using 0.2% (w/v) HgCl₂ for 20 min without compromising germination. When cultured on MS medium containing 0.5 mg/L 2,4-D, seed, stem-node, and 1-week-old seedling explants produced abundant callus. A 2.0 mg/L BA treatment achieved 100% shoot induction, with stem-node explants yielding the highest shoot proliferation (3.90 ± 0.31 shoots/explant), followed by 1-week-old seedlings (2.30 ± 0.21 shoots/explant) and seed explants (1.60 ± 0.16 shoots/explant). Rooting was most effective on half-strength MS medium supplemented with 20.0 mg/L IBA, producing an average of 4.30 ± 0.83 roots per shoot in shoot-tip-deprived explants. The rooted plantlets successfully acclimatized, attaining a 100% survival rate in a 1:1:1 mixture of sterile soil, cocopeat, and vermiculite. These findings provide a robust platform for the sustainable propagation and conservation of C. lenis in response to its growing vulnerabilities.

Owing to habitat modifications and climate change, Sphagnum moss has gradually disappeared from many tropical areas. In Thailand, Sphagnum cuspidatulum Müll. Hal., which was one of the most abundant species in the past, experienced a significant decline in 2022. The in vitro conservation of this species in an axenic culture in the laboratory has not been attempted, and therefore our work focused on the gametophytic cultivation of S. cuspidatulum using the tissue culture technique. After collecting samples in the field, a gametophyte of S. cuspidatulum was prepared by growing the moss in a growth chamber for three months to induce shoot tip elongation. The explants were cultured for six weeks in different formulas of culture media, initial pHs of the treatments, sugar types, and sugar concentrations. The results showed that the highest dry weight was produced with the 1/6MS treatment, followed by the 1/8MS and 1/4MS treatments. Different initial pHs did not affect the dry weight or total chlorophyll content. It was also found that the pHs of all of the treatments gradually declined during cultivation to less than 3.0. When we supplemented the media with sugar, the 1/4MS treatment supplemented with 1.5% to 2% glucose had the highest dry weight. This study was the first to use MS media for Sphagnum cultivation rather than traditional media such as Knop and B5. The results demonstrated the potential of using micropropagation for the mass production and ex situ conservation of S. cuspidatulum in Thailand.

An account of the genus Phyllocyclus (Gentianaceae) for Thailand is presented. Three species are recognized, including two recently reported species, Phyllocyclus petelotii and P. parishii. A key to the Thai species, descriptions, illustrations, and conservation status are provided.