Maize seedlings (Zea mays L. PR 32w86) were grown hydroponically in a nutrient solution mixed with treated wastewater (TWW) or with dialyzed treated wastewater (DTWW) obtained after the dialysis process with a cutoff at 6000–8000 Da. Within 70 min of exposure, pressurized water flow through the excised roots was reduced massively by 46% (for primary TWW, after physical treatment) and 22% (for secondary TWW, after biological treatment). In contrast, with primary and secondary DTWW, it was only slightly decreased by 22%. On the other hand, cell wall pore sizes of these roots were little reduced: by (14–27%) for primary and secondary TWW and (6–9%) for primary and secondary DTWW. Primary and secondary effluents after either TWW or DTWW affected root elongation severely by (58–76%), while reduced leaf growth rate by (26–70%) and transpiration by (14–64%). The fresh and dry plant’s weight in soil growth was also significantly affected but not with secondary DTWW. These results appeared simultaneously to involve phytotoxic and physical-clogging consequences. First, the inhibition in hydraulic conductivity through live roots (i.e., phytotoxic, and physical effects) after exposure to secondary DTWW was 22%, while through killed roots accepted after hot alcohol disruption of cell membranes (i.e., physical effects only) was only by 14%. Second, although DTWW affected root elongation severely by 58%, cell wall pore sizes of the same roots were little reduced by 6%. We conclude that large molecular weight fraction, which remained after the dialysis process, may have produced physical and phytotoxic effects on root water permeability and plant growth.
Bibliographical noteFunding Information:
This work was supported by the European Union Peacebuilding Initiative (EUPI) under the "Unity and Diversity in Nature and Society" project [project agreement ENI/2019/412-148]. Also, it was supported partially by the Ministry of Science, Technology and Space of Israel and the Al-Qasemi Research Foundation. The authors gratefully acknowledge this financial support. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in, or financial conflict with, the subject matter or materials discussed in the manuscript, apart from those disclosed.
© 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
ASJC Scopus subject areas
- Agronomy and Crop Science
- Water Science and Technology
- Soil Science