Research Information System
JOURNAL OF APPLIED PHYCOLOGY, vol.38, no.2, pp.1341-1352, 2026 (SCI-Expanded, Scopus)
Increasingly frequent harmful cyanobacterial blooms promote the production and release of microcystins (MCs) into freshwater systems. Irrigation with bloom-impacted water introduces both algal cells and dissolved MCs into agriculture, impairing crop physiology and leading to toxin accumulation in edible tissues, thereby threatening food safety. This study compared the effects of two exposure pathways (dissolved toxins versus intracellular toxins from lysed cells) on two leaf vegetables, using both MC-producing and non-MC-producing Microcystis aeruginosa strains for comparison. Basella alba L. (Malabar spinach) and Ipomoea aquatica Forsk (water spinach) were hydroponically exposed for 13 days to cell-free filtrate (TF, containing extracellular MCs at 7.9 ng L-1) and cell lysate (TL, containing intracellular MCs at 25.5 ng L-1) from toxigenic algae, alongside analogous non-toxic treatments. The two species exhibited contrasting sensitivity. While non-toxic treatments induced limited effects, TL exposure severely inhibited water spinach growth (up to 35% reduction in plant height) and induced strong oxidative stress. In contrast, Malabar spinach showed enhanced leaf development under TL, indicating greater tolerance. Photosynthetic performance showed transient stimulation followed by specie-specific acclimation. MCs accumulated in roots > leaves > stems for both species under toxic treatments. The highest accumulation occurred in TL-treated water spinach roots (0.90 +/- 0.01 ng g(-1) wet weight), a level 2.4-fold higher than in TF-treated roots. Estimated daily intake for adults remained below the WHO tolerable threshold. These findings demonstrate that the release of intracellular toxins substantially increases crop exposure and physiological stress, strongly discouraging the direct use of bloom-impacted water for agricultural irrigation to safeguard crop productivity and food safety.