Page 22 - Climate Conference - EBook 2023: Al-Qasemi Academy

Phytotoxic effects of treated wastewater used for irrigation
on root hydraulic conductivity and plant growth of maize
seedlings (Zea mays L. PR 32w86)
Dr. Sare Asli

Manager of the Institute of Science and
Technology Education – Al-Qasemi Academic College

ABSTRACT
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 cut-off 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, primary and secondary DTWW 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
the large molecular weight fraction, which remained after the dialysis process, may have
.produced physical and phytotoxic effects on root water permeability and plant growth

Keywords: phytotoxicity, agricultural irrigation, root clogging, hydraulic conductivity

Biography: Asli, S., Massalha, N., Diab, M., & Hugerat, M. (2022). Phytotoxic Effects of
Treated Wastewater Used for Irrigation on Root Hydraulic Conductivity and Plant Growth of
Maize Seedlings (Zea mays L. PR 32w86). Irrigation Science, 1-12.

Asli S., Diab M., Hugerat M., Haj-Zaroubi M., (2023). Hydroxytyrosol increases the salt
tolerance of maize (Zea mays L.) and wheat (Triticum aestivum L.) by expanding the pores’
diameter at the root cell wall. Theoretical and Experimental Plant Physiology. Accepted
with revisions