Proline accumulation as a response to salt stress in 30 wheat (Triticum aestivum L.) cultivars differing in salt tolerance

Abstract

The effects of NaCl salt (EC = 16 dS m -1 ) on water potential, and accumulation of proline, Na + and K + in leaves on the main stem of 30 wheat cultivars (Triticum aestivum L.) at awn appearance and 20 days after anthesis (20 DAA) were evaluated in a greenhouse experiment. Plants were arranged in a according to a randomized complete block design with factorial treatments in three replications. Proline accumulation at 20 DAA increased with increasing salt stress. This increase was 27.4-fold with the salt-sensitive cultivar ''Ghods,'' while the mean was 5.2-fold for 19 salt-resistant cultivars. Positive correlations between proline, and K + + Na + concentrations associated with higher sensitivity to salt stress indicated that proline may not have a protecting role against salt stress. No correlation was observed between leaf proline and water potential. Almost no contribution to the osmotic adjustment seems to be made by proline. The contribution made by proline to the osmotic adjustment of plants at 20 DAA was 0.69 bar, whereas that made by K + and Na + was 2.11 and 4.48 bar, respectively. The 30 wheat CV s used in this experiment showed different performances regarding the traits observed. Eleven of them showing the higher stress sensitivity indices had the highest level of proline and Na + concentrations. They were considered to be salt-sensitive cultivars. Among the others, nine cultivars showed salt tolerance with almost the same Na + and proline concentrations, but a higher K + /Na + selectivity of ions from leaf to grains. In 10 of the cultivars, Na + and proline concentrations were low, indicating the presence of a salt avoiding mechanism.

Pre-sowing Seed Treatment with Proline Improves some Growth, Biochemical aspects, yield quantity and quantity of two sunflower cultivars grown under seawater salinity stress

“…Table 3 shows that salinity levels (S1 and S2) caused significant and gradual increases in the proline content of sunflower two cultivars leaves with increasing salinity levels compared with control plants (S0). The increase in proline levels due to salinity was also demonstrated by Poustini et al, (2007). Proline accumulates in larger amounts than other amino acids in salt stressed plants (Abd El-Samad et al, 2011;Taie et al, 2013 andAbdelhamid et al, 2013a).…”

Exploring ion homeostasis and mechanism of salinity tolerance in primary tritipyrum lines (Wheat× Thinopyrum bessarabicum) in the presence of salinity

“…The reports about the role of proline on salinity tolerance are different. Some researchers indicated that there are no relations between proline content and salinity tolerance (Lutts et al 1996;Poustini et al, 2007). Lutts et al(1996) found no relationship between proline content and salt tolerance in rice cultivars.…”

“…Thus, this parameter has been supported as a criterion of salt stress tolerance (Ashraf and Harris, 2004). However, some researchers have found that there is no correlation between leaf proline and salt tolerance (Poustini et al, 2007;Lutts et al, 1996).…”

Phenolic content and antioxidant activity in two contrasting Medicago ciliaris lines cultivated under salt stress

“…At the same time, leaves of the salttolerant line TNC 1.8 accumulated more Na in comparison with leaves of the sensitive line TNC 11.9. These results suggested that proline accumulation itself is not sufficient to confer salt tolerance (Poustini et al 2007). This led us to hypothesize a mechanism of leaf vacuolar Na sequestration within the tolerant line TNC 1.8 under salt stress (Debez et al 2006).…”