Comparative effects of salt-stress and alkali-stress on the growth, photosynthesis, solute accumulation, and ion balance of barley plants

Abstract

We compared the effects of salt-stresses (SS, 1 : 1 molar ratio of NaCl to Na 2 SO 4 ) and alkali-stresses (AS, 1 : 1 molar ratio of NaHCO 3 to Na 2 CO 3 ) on the growth, photosynthesis, solute accumulation, and ion balance of barley seedlings, to elucidate the mechanism of AS (high-pH) damage to plants and the physiological adaptive mechanism of plants to AS. The effects of SS on the water content, root system activity, membrane permeability, and the content of photosynthetic pigments were much less than those of AS. However, AS damaged root function, photosynthetic pigments, and the membrane system, led to the severe reductions in water content, root system activity, content of photosynthetic pigments, and net photosynthetic rate, and a sharp increase in electrolyte leakage rate. Moreover, with salinity higher than 60 mM, Na + content increased slowly under SS and sharply under AS. This indicates that high-pH caused by AS might interfere with control of Na + uptake in roots and increase intracellular Na + to a toxic level, which may be the main cause of some damage emerging under higher AS. Under SS, barley accumulated organic acids, Cl − , SO 4 2− , and NO 3 − to balance the massive influx of cations, the contribution of inorganic ions to ion balance was greater than that of organic acids. However, AS might inhibit absorptions of NO 3 -and Cl -, enhance organic acid synthesis, and SO 4 2− absorption to maintain intracellular ion balance and stable pH.

Tyrosine-priming modulates phenylpropanoid pathway in maize grown under different pH regimes

“…In this aspect, growth reduction under high temperature (Mahmood et al 2010), drought (Azhar et al 2011) and saline medium (Kaya et al 2013) has been well studied. Contradictory reports about plant growth at unfavourably low (Fan and Wang 2000) and high pH (Yang et al 2007;2008a, c, 2009) are available showing differential pattern varying from species to species. Comprehensive study ranging from acidic to alkaline pH is scant up to our knowledge.…”

Model Examination for the Effect of Treading Stress on Young Green Barley (<i>Hordeum vulgare</i>)

“…The alkali stress induced severe reductions in water content, root system activity, and photosynthetic pigment contents, and a sharp increase in the electrolyte leakage rate. These results indicate that a high pH level from alkaline salts (NaHCO 3 and Na 2 CO 3 ) might damage the root structure and functions such as absorption of water and ions and contents of photosynthetic pigments [6].…”

Integrated proteomics and metabolomics for dissecting the mechanism of global responses to salt and alkali stress in Suaeda corniculata

“…The primary step in energy production in the biosphere, photosynthesis, is inhibited by salt and alkali stress (Ma et al 1997;Yang et al 2009). Photosynthetic capacity has been observed to be much lower under both salt and alkali stresses than in control plants in the glycophytes wheat and barley, and the inhibition was more severe under alkali stress than salt stress (Yang et al 2008c).…”