Articles
The effect of alternating irrigation with fresh and saline water on the aesthetic quality, ion accumulation and water relations of Hibiscus plants
Article number
1345_49
Pages
367 – 372
Language
English
Abstract
Applying saline water resources for irrigation ornamental plants is becoming a widespread practice in urban areas in arid and semi-arid regions, but it can restrict plant growth and lead to environmental problems.
A strategy to reduce the adverse effects of saline water irrigation is the alternate irrigation with fresh and saline water at different phases or different sides of the rooting zone, but this irrigation practice is still not well understood.
In this experiment, 120 hibiscus plants (Hibiscus rosa-sinensis) were grown in a commercial substrate with the root system divided equally between two plastic pots (3 L). Plants were subjected to three irrigation treatments lasting 6 months: control (both sides irrigated with freshwater, 0.8 dS m‑1; F), a saline treatment (both sides irrigated with moderate saline water, 4.0 dS m‑1; S) and a fresh-saline treatment (half of the root system was irrigated with freshwater, 0.8 dS m‑1 and the other half was irrigated with severe saline water, 8.0 dS m‑1; F-S). All the plants were irrigated daily to field capacity.
Results showed that leaf fresh weight was affected more by moderate saline treatment (S) than by alternating fresh and severe saline water (F-S), while plant height was reduced similarly in both treatments.
Plants of F-S treatment were those with greater number of flowers per plant throughout the experiment.
Both saline irrigation treatments induced active osmotic adjustment, especially plants with both sides of the root system irrigated with saline water.
Saline treatment affected leaf colour and relative chlorophyll content and induced an important decrease of its fresh weight due to the leaf tissue dehydration (decrease in leaf water potential) and a high Cl and Na accumulation in the plant tissues.
When alternating fresh and saline water irrigation (F-S) was used, most of the adverse effects were mitigated.
A strategy to reduce the adverse effects of saline water irrigation is the alternate irrigation with fresh and saline water at different phases or different sides of the rooting zone, but this irrigation practice is still not well understood.
In this experiment, 120 hibiscus plants (Hibiscus rosa-sinensis) were grown in a commercial substrate with the root system divided equally between two plastic pots (3 L). Plants were subjected to three irrigation treatments lasting 6 months: control (both sides irrigated with freshwater, 0.8 dS m‑1; F), a saline treatment (both sides irrigated with moderate saline water, 4.0 dS m‑1; S) and a fresh-saline treatment (half of the root system was irrigated with freshwater, 0.8 dS m‑1 and the other half was irrigated with severe saline water, 8.0 dS m‑1; F-S). All the plants were irrigated daily to field capacity.
Results showed that leaf fresh weight was affected more by moderate saline treatment (S) than by alternating fresh and severe saline water (F-S), while plant height was reduced similarly in both treatments.
Plants of F-S treatment were those with greater number of flowers per plant throughout the experiment.
Both saline irrigation treatments induced active osmotic adjustment, especially plants with both sides of the root system irrigated with saline water.
Saline treatment affected leaf colour and relative chlorophyll content and induced an important decrease of its fresh weight due to the leaf tissue dehydration (decrease in leaf water potential) and a high Cl and Na accumulation in the plant tissues.
When alternating fresh and saline water irrigation (F-S) was used, most of the adverse effects were mitigated.
Authors
S. Álvarez, P.A. Nortes, J.R. Acosta-Motos, M.J. Sánchez-Blanco
Keywords
salinity, ornamental plants, irrigation, root system, osmotic adjustment, ion uptake, flowering
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