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Zingiberaceae is widely distributed in Malaysia, with 750 species and 31 genera. This family comprises a different number of subfamilies and genera according to different taxonomic classification methods — classical taxonomy: one subfamily and four tribes vs molecular taxonomy: four subfamilies and six tribes. However, the taxonomic classification of Zingiberaceae is still debated, especially the classical taxonomy. It is due to some Zingiberaceae species showing cryptic morphologies that make it difficult to classify them through classical taxonomy, which refers to the unique morphological characteristics of a tribe/species. Therefore, accurate taxonomic classification is required by using a molecular approach. In this study, 20 selected species of Zingiberaceae collected from the Agricultural Conservatory Park, Institute of Bioscience (IBS), Universiti Putra Malaysia (UPM) were taxonomically classified using a molecular method with the help of three random amplified polymorphic DNA (RAPD) and three inter simple sequence repeat (ISSR) markers until the tribe level. The combined RAPD and ISSR unweighted pair group method with arithmetic mean (UPGMA) phylogenetic tree was comparable to Zingiberaceae’s current molecular and classical taxonomy. The 20 selected species were grouped into three tribes (Alpinieae, Zingiberaceae, and Globbeae). This finding has contributed additional biological information to better manage the 20 Zingiberaceae species in the Agricultural Conservatory Park, IBS, UPM. Further studies are needed to explore the genetic diversities and properties of Zingiberaceae species.

The chalcone synthase (CHS) gene families are known to be conserved in plants and have been well-studied in many plants, and they have an important role in the physiological and biological processes of plants. One of the studied CHS gene families is the CHS1 gene. CHS1 gene is known for its function in the flavonoid biosynthetic pathway. However, not many studies have been reported on the CHS1 gene in the Commelinids clade, especially the evolution of this gene within three families: Zingiberaceae, Costaceae, and Poaceae. Thus, this study aimed to perform a preliminary in silico comparative analysis of the CHS1 gene across these three families. Through this in silico comparative analysis, 20 partial sequences of the CHS1 gene, which are restricted to 565 bp regions, were analysed. The partial sequences were extracted from the National Center for Biotechnology Information database comprised of 16 Zingiberaceae species, three Costaceae species, and one Poaceae species. From the analysis, these targeted regions showed a low polymorphic site (18.23%) with 103 positions of single nucleotide polymorphisms and three mutations (substitution, insertion, and deletion). Meanwhile, phylogenetic analysis showed no clear evolutionary pattern within the three studied families. In conclusion, the studied partial sequences of the CHS1 gene in Zingiberaceae, Costaceae, and Poaceae showed that the gene is conserved within the Commelinids clade. Further studies to understand the consequences of low polymorphism and mutations as well as adaptive evolution in the CHS1 gene, accompanied by biochemistry and gene expression studies, should be done in these 20 species of Zingiberaceae, Costaceae, and Poaceae.

Mitigating climate change requires the identification of tree species that can tolerate water stress with fewer negative impacts on plant productivity. Therefore, the study aimed to evaluate the water stress tolerance of young saplings of C. erectus and M. alba under three soil water deficit treatments (control, CK, 90% field capacity, FC, medium stress MS, 60% FC and high stress, HS, 30% FC) under controlled conditions. Results showed that leaf and stem dry weight decreased significantly in both species under MS and HS. However, root dry weight and root/shoot ratio increased, and total dry weight remained similar to CK under MS in C. erectus saplings. Stomatal conductance, CO2 assimilation rate decreased, and intrinsic water use efficiency increased significantly in both species under MS and HS treatments. The concentration of hydrogen peroxide, superoxide radical, malondialdehyde and electrolyte leakage increased in both the species under soil water deficit but was highest in M. alba. The concentration of antioxidative enzymes like superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase also increased in both species under MS and HS but was highest in C. erectus. Therefore, results suggest that C. erectus saplings depicted a better tolerance to MS due to an effective antioxidative enzyme system.

Low water availability predicted under climate change is a major abiotic factor limiting plants growth and productivity. In this study a greenhouse experiment was conducted on three important tree species of arid environment: Conocarpus erectus (CE), Acacia modesta (AM), and Salix tetrasperma (ST). Young saplings were subjected to control (C), medium (MWD) and severe soil water deficit (SWD) treatments and response was evaluated. Results showed that in all the three species leaf, stem and root dry weight production remained similar to C under MWD treatment but decreased significantly under SWD. The highest decrease in total dry weight was noticed in ST and the lowest was evidenced in AM under SWD. Root:shoot ratio increased significantly in both CE and AM under MWD and SWD. Furthermore, chlorophyll content decreased while proline content increased significantly in both MWD and SWD treatments. The production of oxidants (hydrogen peroxide and superoxide anions) and antioxidants (superoxide dismutase, catalase, peroxidase and ascorbate peroxidase) increased significantly under both MWD and SWD treatments and were the highest in AM in both MWD and SWD treatments. Therefore, we may conclude that all the three species can tolerate medium water stress due to increased root production and an effective antioxidant defense mechanism.