Morpho-anatomical adaptations of dominantly grown wild Datura inoxia to wastewater resource: Productivity and ecological issues

Abstract

With the increasing global water scarcity, wastewater irrigation has become widespread, but it can have detrimental ecological consequences. Although wastewater contains valuable nutrients for plants, improper treatment or the use of untreated wastewater in irrigation can negatively impact soil fertility and plant growth. This study is divided into two parts: firstly, a phytosociological survey was conducted to identify plant species with the highest importance value index (IVI) in the vicinity of wastewater-irrigated areas. Secondly, a comparative morpho-anatomical analysis was carried out to investigate the morpho-anatomical adaptations of the species with the highest IVI under wastewater irrigation compared to normal water irrigation. The results of the phytosociological survey revealed the presence of 51 plant species in the vicinity of the wastewater-irrigated areas, with varying relative densities and coverage. Datura inoxia exhibited the highest IVI (28.79), followed by Xanthium strumarium (24.34), while Lippia nodiflora showed the lowest IVI (1.86). The morphological growth of D. inoxia was superior under normal water irrigation, but the average root length was greater under wastewater irrigation. Regarding cell anatomy, cell thickness and cell area characteristics in the dermal, ground, and vascular tissues of the stem and root tended to be greater under wastewater treatment. However, the opposite trend was observed in leaf anatomical analysis, possibly due to the combined effect of wastewater and climatic conditions. Stem and root xylem thickness were greater under wastewater irrigation, whereas phloem thickness was higher under normal water irrigation. The number of vascular bundles in the stem, root, and leaf was higher under wastewater treatment compared to normal water irrigation, but their arrangement was circular in the latter and scattered under wastewater irrigation. Datura inoxia demonstrated strong adaptive potential under wastewater irrigation, as indicated by its highest relative density, coverage, and IVI, suggesting its suitability for phytoremediation. However, due to the low relative density, coverage, and IVI of many other species, the use of untreated wastewater for irrigation cannot be appreciated.