Ascorbic acid (AsA) or Vitamin C is an antioxidant molecule and plays an important role in many biological processes in plants. GDP-D-mannose pyrophosphorylase (GMP or VTC1) catalyzes the synthesis of GDP-D-mannose, which is a precursor for AsA production and is used for cell wall polysaccharide and glycoprotein synthesis. In rice, the OsVTC1 gene consists of three homologs, including OsVTC1-1, OsVTC1-3 and OsVTC1-8. In this study, we characterized wild type (WT) and OsVTC1-1 RNAi lines (RI1-2 and RI1-3) and showed that the transcript levels of most genes in the AsA synthesis pathway, AsA content and leaf anatomical parameters in RNAi lines were reduced, revealing that OsVTC1-1 is involved in AsA synthesis. To further study the role of OsVTC1-1 gene, cell wall monosaccharide composition, transcriptome and proteome were compared, with specific attention paid to their wild type and OsVTC1-1 RNAi lines. Mannose and galactose composition (mole%) were decreased in OsVTC1-1 RNAi lines. Additionally, reduction of cell wall-associated proteins, such as kinesin, expansin, beta-galactosidase and cellulose synthase were observed in OsVTC1-1 RNAi lines. Our results suggest that OsVTC1-1 gene plays an important role in AsA synthesis and in cell wall-related processes.

Fruits and endocarps of 21 species within the genus Premna (Lamiaceae) in Thailand were examined using light (LM) and scanning electron microscopy (SEM) to evaluate taxonomic relevance. Overall, mature fruits were classified into two types: fully developed mericarp (fruit type I) and partly developed mericarp (fruit type II), with three shape patterns: broadly obovoid, narrowly obovoid, and clavoid. Fruit size ranged from 1.52 to 7.48 mm in length and 0.98 to 7.71 mm in width. In LM investigations, the endocarps were classified into three types based on the presence and shape of the protruding structure: saccate-like (protrusion type I), thorn-like (protrusion type II), and no protrusion (protrusion type III). The examination of endocarps under SEM showed that they consist of multilayers of sclerenchyma cells. The shape of the sculpturing cells on the endocarp surface can be divided into two patterns: irregular tetragonal and polygonal, with distinct or obscure straight cell faces. The morphological comparison and phenetic analyses using factor analysis of mixed data (FAMD) show that fruit and endocarp characteristics of Premna hold significant taxonomic value for distinguishing certain related species and classifying within the genus in Thailand. From the first two FAMD dimensions, fruit shape, shape of sculptured cells on the endocarp, and protrusion type of the endocarp are considered as the most significant contributing variables. The findings also support the reinstatement of species previously synonymized with P. serratifolia, namely P. cordifolia, P. paniculata, and P. punctulata.

Garcinia dulcis (Roxb.) Kurz is a medicinal plant having potential as a source of medicinal ingredients, yet details of its reproductive biology, especially palynological features, remain largely unresearched. Therefore, a detailed description of pollen development and morphology, and pollenkitt production of G. dulcis, based on both light and electron microscopic analysis, was undertaken. The results showed that G. dulcis underwent sequential anther and pollen development with a high production of pollenkitt. Pollenkitt secreted from tapetum degradation was released early into the locular cavity (at the microspore tetrad stage). The occurrences of intinous protrusion (protruding oncus) at pollen aperture and the precocious pollenkitt production were suggested as adaptive features of G. dulcis to assist its biotic pollination, according to its smooth pollen surface. The results obtained provide new insights into the significant palynological traits that would provide baseline data for further research on G. dulcis.

Launaea sarmentosa (Willd.) Kuntze, a threatened coastal species endemic to the Andaman coastline of Thailand, is undergoing significant population decline due to habitat degradation. Despite its ecological and economic importance, limited knowledge exists regarding its anatomical adaptations to coastal environments, knowledge that is essential for effective conservation and restoration strategies. This study aimed to comprehensively investigate the vegetative anatomy of L. sarmentosa and to identify taxonomically significant features that reflect its adaptation to environmental stressors. Samples of leaves, stems, stolons and roots were collected from Mai Khao Beach, Phuket and examined using paraffin embedding and light microscopy techniques. The results revealed several adaptive features, including amphistomatic leaves, thick cuticlar layers, homobaric leaf structure and the formation of periderm in stems and roots. Stomatal density was significantly higher on the adaxial surface compared to the adaxial surface, indicating differential regulation of gas exchange. The presence of a thick cuticle and epidermis further highlights its adaptations to the harsh coastal environment, characterized by high light intensity and drought conditions. Stolons exhibited chlorenchyma and stomata, suggesting their role in photosynthesis and water regulation. These anatomical traits reflect the ability of L. sarmentosa to thrive in dune habitats and provide essential information for future conservation and habitat restoration initiatives. Understanding these adaptations is crucial for the effective preservation and rehabilitation of this species.

The lotus (Nelumbo nucifera Gaertn.) is an ornamental aquatic plant, highly valued in Asian cultures for its religious symbolism, culinary uses, and medicinal properties. However, the lotus exhibits low genetic diversity in nature, which limits the genetic resources available for breeding programs. Gamma irradiation is an effective method for inducing genetic variation in lotus breeding. The present study examines the gamma sensitivity of lotus seedlings, along with the morphological and anatomical changes induced by various gamma dosages. The results showed that high-dose gamma irradiation (≥100 Gy) significantly inhibited seedling growth and altered most anatomical parameters, each exhibiting distinct dose–response patterns except for midrib diameter. The 100 Gy treatment resulted in the maximum stem diameter, while root diameter peaked at 500 Gy, and the highest dose (600 Gy) produced the largest petioles. Gamma irradiation also triggered tannin accumulation and reduced aerenchyma formation in the leaves. The obtained results demonstrate organ-specific responses to gamma irradiation in the lotus, with leaves being the most sensitive, while petioles, stems, and roots exhibited more variable dose-dependent effects.