Leaf photosynthesis, chlorophyll fluorescence and ion content of barley (Hordeum vulgare) in response to salinity

ABSTRACT

Eight barley genotypes contrasting in their salinity tolerance were assessed for their chlorophyll fluorescence, photosynthetic performance, lipid peroxidation level and ionic content. A pot experiment was conducted in Borj-Cedria (Tunisia), in a wire house with a glass roof to avoid rainfall. The assay consisted of three treatments (0, 100 and 200 mM NaCl) with eight barley genotypes following a completely randomized design. Each pot was considered as one replicate and nine replicates were used for each genotype and treatment. The salt-tolerant genotypes Kerkna and Tichedrett recorded the highest tolerance for photosynthesis and potassium accumulation, whereas the susceptible genotypes were mostly affected at severe salinity. Contrasting behavior was noted for fluorescence attributes, while PSII yield was unchanged reflecting good protection against photodamage. Photosynthetic performance, enhanced water use efficiency, maintained leaf K⁺ and oxidative defense remain the key components for tolerance mechanisms. Salt-tolerant barley could be suitable for management of salt-affected soils.

KEYWORDS:

• chlorophyll fluorescence
• growth performance
• Hordeum vulgare
• K⁺ retention
• MDA content
• photosynthesis
• photosystem
• salinity tolerance
• stomatal conductance

Abbreviations

A	=	CO2 absorbance
ABA	=	abscissic acid
Ci	=	substomatal CO2 concentration
E	=	transpiration
ETR	=	electron transport rate
gs	=	stomatal conductance
MDA	=	malondialdehyde
PAR	=	phtosynthetic active radiation
PSII	=	photosystem II
NPQ	=	non-photochemical quenching
WUE	=	water use efficiency

Funding

This work was supported by NEPAD-NABnet (New partnership for African's Development–North Africa Barley–net) project and a personal grant to Dorsaf Allel from Mitsubishi Corporation (Japan).