Improving photosynthesis and growth in summer crops irrigated with electro-chemical modified water

We evaluated the effects of treating irrigation water with a coaxial flow variator (CFV) on the morphophysiology of pot-cultivated test species, including cucumber (Cucumis sativus), lettuce (Lactuca sativa), and sorghum (Sorghum vulgare), in early stages of growth. We demonstrated that CFV caused a lower oxidation reduction potential (ORP), increased pH and flow resistance and inductance. The treatment also changed the absorbance characteristics of water in specific spectral regions, likely associated with greater stretching and reduced bending vibrations compared to untreated water. While assimilation rate and photosynthetic efficiency were not significantly affected at 60 days after sowing, treated water increased the stomatal conductance to water vapour gsw (+79%) and the electron transport rate ETR (+10%) in cucumber, as well as the non-photochemical quenching NPQ (+33%) in sorghum. Treated water also reduced leaf temperature in all species (-0.86 ◦C on average). This translated into improved plant biomass (leaves: +34%; roots: +140%) and reduced leaf-to-root biomass ratio (-42%) in sorghum, allowing both faster aerial growth and soil colonization, which can be exploited to improve plant tolerance against abiotic stresses. In the C3 species cucumber and lettuce, plant biomass was instead reduced, although significantly in LE only, while the leaf-to-root biomass ratio was generally enhanced, a result likely profitable in the cultivation of leafy vegetables. In view of the positive results obtained in the C4 species sorghum in terms of growth, investigations in maize will be very interesting for producing more grain yield/biomass with less water in a contest of increasing drought due to climate change.