Toxicological effect of arsenic (V) on growth and histology of duckweeds (Lemna minor)

• Main Authors: Chan, Yee Wa C., Donato, Alandeck Q., Gomez, Antonietta Ramona V.
• Format: text
• Language: English
• Published: Animo Repository 1992
• Subjects: Arsenic > Toxicology; Weed control
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/5943
• Institution: De La Salle University

Duckweeds (Lemna minor) were used as a representative of plant species for their being sensitive to a wide variety of toxicants. Test species was grown under laboratory light condition of 11:13 light and dark period in an aqueous dilution of Hoaglands culture media (1:1 vol/vol with distilled water) at pH of 7.0. This laboratory culture environment was found suitable for the maximum normal growth of duckweed (SI value of 2.5).Toxicological effects of varying concentrations of As (V) ranging from 0.0, 0.1, 1.0, 3.0, 5.0, 10.0, and 25.0ppm was assessed based on growth measured in terms of frond production and biomass content. Histological changes in treated duckweed with 25.0ppm As were also noted. In As concentration of 0.1-1.0ppm, growth of Lemna minor approximated the control. However, concentration of As from 3.0ppm or higher is lethal to duckweeds as evidenced by an inhibition of growth. An overall reduction of 20-40 percent in biomass over the control at 0.1-25.0 ppm As was observed. Histological studies were conducted on treated duckweed showing a generalized chlorosis accompanied by disruption in chloroplast integrity and degeneration of intact chloroplast. The cells in the vascular bundle were proliferated or severely collapsed and disruption of the mesophyll and epidermal layer caused a 24 percent reduction in the thickness of duckweed frond. Accumulation of As by duckweeds may enhance the toxic effect on their histological processes which influences their total process of growth and survival.