Research Information System
5th INTERNATIONAL NOWRUZ CONFERENCE ON SCIENTIFIC RESEARCH, Antalya, Turkey, 17 - 21 March 2022, pp.59-72
Salt stress is one of the most characteristic abiotic stresses, that affects plant growth and restrict the use
of agricultural areas. In order to ensure sustainable food production, it is essential to increase the salt
tolerance of plants. Melatonin (Mel) is known to behave as an antioxidant in plant cells and as a
membrane stabilizer, and to be involved in plant growth and development, and the external application
of Mel has been shown to reduces stress damage. The aim of this study was to determine the relationship
between leaf soluble sugar content and water status/changes in salt stress tolerant/sensitive red and white
beet cultivars with the external application of Mel. Four beet cultivars, two red (Beta vulgaris 'Scarlet
Supreme' and Beta vulgaris var. crassa 'Ruby Queen') and two white (Beta vulgaris 'Rodeo' and Beta
vulgaris 'Ansa'), were grown in Hoagland’s nutrient solution until four true leaves emerged, and were
5th INTERNATIONAL NOWRUZ CONFERENCE ON SCIENTIFIC RESEARCH
March 17-21, 2022/ Antalya, TURKEY
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harvested 12 days after 50 µM Mel, 150 and 250 mM NaCl applications. The beet leaves’ water potential
and water loss values were measured. The leaves’s osmotic potential values were determined with an
osmometer, and the soluble sugar contents using HPLC-RID. Soluble sugar contents (fructose, glucose,
sucrose) increased in the NaCl treatments groups compared to the control group, while the contents in
the Mel + NaCl application groups decreased compared to the stress groups. Water and osmotic potential
values decreased with NaCl application in red and white beet cultivars, but increased with Mel
application in the control and stress groups. The decrease in water loss values with NaCl application in
the beet leaves did not change statistically significantly (P < 0.05) change with Mel application. Soluble
sugar (glucose and sucrose) content exhibited a significant correlation (P < 0.01 and P < 0.05) with
water and osmotic potential values in four beet cultivars.