Study: Selenium Treatment Shown to Protect Olive Trees Against Salt Stress

Salt stress is a major problem in olive farming as it negatively affects the growth and productivity of olive trees. Selenium treatments may be the answer.
Kefalonia, Greece
By Ephantus Mukundi
Nov. 30, 2021 12:20 UTC

Olive trees grow­ing in saline con­di­tions expe­ri­ence salt stress, which causes meta­bolic and phys­i­o­log­i­cal prob­lems such as low water intake, reduced pho­to­syn­the­sis and nutri­tional imbal­ance.

However, a recent study by agri­cul­tural researchers at the University of Perugia, in Italy, shows that sele­nium bio­for­ti­fi­ca­tion can reduce stress lev­els in olive trees by increas­ing the water con­tent of the leaves, enhanc­ing pho­to­syn­the­sis and reduc­ing toxic effects.

The results sug­gest a pos­i­tive effect of an appro­pri­ate amount of sele­nium, although with dif­fer­ent inten­si­ties depend­ing on the cul­ti­var, and the vigor of the olive tree pro­lif­er­ated shoots in vitro,” the study’s authors wrote.

See Also:Olive Oil Research News

While the olive tree is quite tol­er­ant to salin­ity, salt stress affects the plant by increas­ing the pro­duc­tion of reac­tive oxy­gen species in the long term, includ­ing hydroxyl rad­i­cal and hydro­gen per­ox­ide.

These com­pounds play a cen­tral role in oxida­tive cell dam­age and in extreme cir­cum­stances, the plants get dehy­drated and even­tu­ally die.

By under­tak­ing this study, the researchers wanted to inves­ti­gate, eval­u­ate and estab­lish the likely effects of sele­nium when admin­is­tered at dif­fer­ent con­cen­tra­tions to Arbequina trees expe­ri­enc­ing saline stress.

The sele­nium effects on the trees were stud­ied by mon­i­tor­ing phys­i­o­log­i­cal and bio­met­ric indices in rela­tion to the plant’s abil­ity to exchange gases, its growth and the water con­tent of the leaves.

In addi­tion, the researchers mon­i­tored bio-mol­e­c­u­lar para­me­ters includ­ing sele­nium and pro­line lev­els in the leaves and roots.

The study found that olive trees exposed to high lev­els of salin­ity had reduced foliar pho­to­syn­the­sis and height­ened sub-stom­atal con­cen­tra­tion of car­bon diox­ide.

Researchers attrib­uted the increase of CO2 in the plants to low pho­to­syn­the­sis result­ing from non-stom­ata effects and clo­sure of the stom­ata due to destruc­tion of the pho­to­sys­tem.

When the plants were treated with sele­nium – in the form of sodium sele­nate – there was a remarked reduc­tion of the neg­a­tive effects result­ing from the high lev­els of sodium chlo­ride. The olive trees expe­ri­enced a higher rate of pho­to­syn­the­sis, improved water con­tent in the leaves and bet­ter growth.

This is the first study demon­strat­ing that sele­nium has pro­tec­tive prop­er­ties against the neg­a­tive effects of sodium chlo­ride on olive trees.

However, the researchers con­cluded that more stud­ies need to be con­ducted in this area to deter­mine the effects of sele­nium bio­for­ti­fi­ca­tion on olive pro­duc­tion and oil qual­ity.


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