Ģ����ý

Doctoral researcher Trần Thị Anh Thoa presenting her doctoral thesis in Plant Physiology before the institutional Doctoral Thesis Assessment Committee at the VNUHCM–University of Science (HCMUS).

On 17 June 2026, at the VNUHCM–University of Science (HCMUS), doctoral researcher Trần Thị Anh Thoa (2019 cohort) successfully defended her doctoral thesis in Plant Physiology. The thesis, entitled “Contribution to understanding and controlling the development of water hyacinth Eichhornia crassipes (Mart.) Solms”, was supervised by Associate Professor Dr Bùi Trang Việt and Dr Đỗ Thường Kiệt.

Water hyacinth (Eichhornia crassipes) is an aquatic plant species characterised by rapid growth and the capacity to form dense vegetative mats on water surfaces through asexual reproduction, particularly via stolon development. The proliferation of water hyacinth in freshwater bodies can adversely affect aquatic ecosystems, waterway navigation, and water resource exploitation and utilisation. However, current control methods for this species remain limited in terms of efficacy and cost-effectiveness.

In this study, doctoral researcher Trần Thị Anh Thoa focused on elucidating the growth characteristics and stolon-forming capacity of water hyacinth, whilst investigating the impact of sodium chloride (NaCl) in controlling the development of the aquatic weed.

The research findings indicate that, under in vitro culture conditions, NAA at a concentration of 0.25 mg/L is capable of stimulating adventitious root development, whereas BA at concentrations of 0.5 – 1 mg/L promotes lateral branching and stolon elongation. These results contribute additional data regarding the role of plant growth regulators in the development of water hyacinth.

Furthermore, the thesis demonstrated the impact of NaCl treatment on water hyacinth. Treatment with 3% NaCl supplemented with 1‰ Tween 20 causes irreversible damage to the leaves, including permanently open stomata, chloroplast deformation, diminished chlorophyll content, impaired photosynthetic activity, and alterations to the fast chlorophyll fluorescence transient (OJIP) curve. The study also recorded the migration and accumulation of Na⁺ and Cl^– ions in the leaves, petioles, and rhizomes, alongside alterations to phytohormone balance within the rhizomes.

Notably, field trial results in a lake with a water hyacinth coverage exceeding 384 m² revealed that spraying 6% NaCl (supplemented with 1‰ Tween 20) over the entire foliar surface significantly reduces survival rates and stolon-forming capacity. Upon repeating the treatment after 4 weeks, approximately 40% of the mother plants failed to recover, and the proportion of plants with stolons decreased to 30% compared to the control group.

The outcomes of the thesis have contributed to a clearer understanding of the growth mechanisms, development, and responses of water hyacinth under salinity stress, whilst opening up novel avenues for researching more efficient and feasible measures to control the expansion of this aquatic plant.

In addition to the achievements realised, the thesis proposes future research directions, such as conducting deeper investigations into phytohormone signalling pathways under salinity stress, as well as optimising NaCl treatment methods for appropriate application in controlling water hyacinth within canals and waterways.

The Assessment Committee determined that the thesis possesses significant scientific value, providing further baseline data for studies on aquatic plant physiology, and officially recognised the work as meeting the doctoral thesis standards of the educational institution.