Photosynthetic responses of a wheat (Asakaze)–barley (Manas) 7H addition line to salt stress

Szopkó, Dóra and Darkó, Éva and Molnár, István and Kruppa, Klaúdia and Háló, Borbála and Vojtkó, András and Molnár-Láng, Márta and Dulai, Sándor (2016) Photosynthetic responses of a wheat (Asakaze)–barley (Manas) 7H addition line to salt stress. PHOTOSYNTHETICA. pp. 1-13. ISSN 0300-3604 (In Press)

Preview

Text Dulai_Photosynthetica2016.pdf - Accepted Version Download (836kB) | Preview

Abstract

The photosynthetic responses to salt stress were examined in a wheat (Triticum aestivum L. cv. Asakaze) – barley (Hordeum vulgare L. cv. Manas) 7H addition line having elevated salt tolerance as compared to the parental wheat genotype. For this purpose, increasing NaCl concentrations up to 300 mM were applied and followed by a 7-day recovery period. Up to moderate salt stress (200 mM NaCl), forcible stomatal closure, parallel with a reduction in the net assimilation rate (PN), was only observed in wheat, but not in the addition line or barley. Since the photosynthetic electron transport processes of wheat were not affected by NaCl, the impairment in PN could largely be accounted for the saltinduced decline in stomatal conductance (gs), accompanied by depressed intercellular CO2 concentration and carboxylation efficiency. Both, PN and nonstomatal limitation factors (Lns) were practically unaffected by moderate salt stress in barley and in the addition line due to the sustained gs, which might be an efficient strategy to maintain the efficient photosynthetic activity and biomass production. At 300mM NaCl, both PN and gs decreased significantly in all the genotypes, but the changes in PN and Lns in the 7H addition line were more favourable similar to those in wheat. The downregulation of photosynthetic electron transport processes around PSII, accompanied by increases in the quantum yield of regulated energy dissipation and of the donor side limitation of PSI without damage to PSII, was observed in the addition line and barley during severe stress. Incomplete recovery of PN was observed in the addition line as a result of declined PSII activity probably caused by enhanced cyclic electron flow around PSI. These results suggest that the better photosynthetic tolerance to moderate salt stress of barley can be manifested in the 7H addition line which may be a suitable candidate for improving salt tolerance of wheat.

Actions (login required)

Edit Item