Satureja khuzistanica Jamzad is a valuable and endemic medicinal plant. Boron and zinc are
essential elements for the vegetative and reproductive growth of plants and have significant effects
on yield, essential oil composition and the seed production of plants. To investigate the effects of
the foliar application of zinc and boron on the growth, yield, seed production and phytochemical
properties of S. khuzistanica, a study was conducted in a factorial experiment with three replicates in
two consecutive years based on a randomized complete block design. The foliar application of boron
(B) at three concentrations (control or distilled water, 0.4% and 0.8% as H3BO3
) and zinc (Zn) at three
concentrations (control or distilled water, 0.3% and 0.6% as ZnSO4
) was carried out. Our results
showed that the foliar application of B resulted in a significant increase in the fresh and dry weights
of plants, the dry weight of stems, drug yield, seed yield, seed germination and 1000-seed weight. At
the same time, the application of B resulted in a significant decrease in seed emptiness. The fresh
and dry weights of plants, drug yield, seed yield, 1000-seed weight and seed germination were also
significantly improved by Zn foliar spraying compared to the control. Application of 0.8% B resulted
in a significant decrease in seed emptiness by 14.16% and 22.37%, as compared to the control. The
foliar spraying of B and Zn improved the total phenolic content, the essential oil content and the
yield and antioxidant activity of S. khuzistanica. Moreover, B application generally concentrated more
carvacrol in the essential oil (in the first experimental year). In contrast, no significant differences
were observed between Zn treatments in carvacrol content and total flavonoids. The use of several
microelements, such as B and Zn, could improve both the quantity and quality of S. khuzistanica.
Additionally, improvement of seed set and seed quality by the foliar spraying of Zn and B may be
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