Acquisition of boron tolerance by salt pretreatment in two sunflower cultivars

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EKMEKÇİ Y., ÇULHA ERDAL Ş., Balkan Nalaciyi S., ÇİÇEK N.

TURKISH JOURNAL OF BOTANY, vol.44, no.2, pp.153-166, 2020 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 44 Issue: 2
  • Publication Date: 2020
  • Doi Number: 10.3906/bot-1910-26
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, BIOSIS, CAB Abstracts, Geobase, Veterinary Science Database, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.153-166
  • Keywords: Boron toxicity, JIP test, photochemical activity, salt pretreatment, slow and fast chlorophyll a fluorescence, sunflower (Helianthus annuus L.), CHLOROPHYLL FLUORESCENCE, EXCESS BORON, PHOTOSYNTHETIC APPARATUS, HELIANTHUS-ANNUUS, ABIOTIC STRESS, SALINITY, RESPONSES, TOXICITY, GROWTH, PLANTS
  • Hacettepe University Affiliated: Yes


This study was carried out to investigate the ameliorative effects of salt pretreatment against B toxicity in two sunflower cultivars (Helianthus annuus L. Sanbro and 'Tarsan-1018') differing in salt tolerance. Seedlings were grown in perlite with modified half-strength Hoagland's solution for 15 days and then they were divided into two groups: salt-pretreated (75 mM NaCl for 5 days) and B-treated (control, 2, 4, and 8 mM B for 10 days). In both cultivars, the biomass of root and shoot decreased depending on B accumulation, especially at 8 mM. The translocation factor values indicated that B uptaken by roots of the genotypes were translocated to the leaves. High B accumulation adversely affected the water balance and membrane integrity of the leaves. Additionally, toxic B levels caused changes in the some JIP tests and slow fluorescence parameters (ABS/RC, TR0/RC, ET0/RC, RE0/RC, DI0/RC, Area, phi(E0), phi(R0) and j(D0), Phi PSII, ETR) of both cultivars and these changes led to a significant decrease in photosynthetic performance (PIABS and PITOTAL) Salt pretreatment ameliorated the damaging effects of toxic B on membrane integrity, water content, and the photosynthetic process; decreased B accumulation; and improved the membrane stability. Both cultivars acquired tolerance against B toxicity with salt pretreatment and survived in increasing boron toxicity. We conclude that sunflower can be used for phytoremediation purposes for boron-contaminated soils. Additionally, this study is the first report to reveal that moderate salt stress pretreatment alleviates B toxicity and provides tolerance to B. This alleviation might be achieved by NaCl to decrease the boron uptake from the roots.