Affiliation:
1. Department of Biology, Faculty of Science, Muğla Sıtkı Kocman University, Muğla, Turkey
Abstract
Determining the mechanisms underlying tolerance to osmotic stress and
salinity during the germination period is an essential task in order to
improve agricultural production in arid and semi-arid areas. In this work,
the seeds of bread and durum wheat cultivars were treated with different
concentrations of polyethylene glycol (PEG)-6000 and NaCl for 1 week, and
half-maximal inhibitory concentrations (IC50) of germination were
calculated. The seeds were then exposed to IC50 values of NaCl and PEG-6000
for 2 days in order to assess their physiological and biochemical
properties. Alpha and beta amylase enzyme activities, the reducing sugar,
total sugar, proline, protein, and H2O2 contents, and DPPH radical
scavenging activity of the seeds were determined by spectrophotometric
methods. The results showed that the bread wheat seeds had a much higher
tolerance to excess salt and osmotic stress than the durum wheat seeds. In
particular, the average IC50 value of NaCl for the bread wheat cultivars was
almost twice that for the durum wheat cultivars. The imbibition test
revealed that the water uptake capacity of the seeds did not explain the
difference in tolerance to these stress conditions. On the other hand, the
bread wheat seeds exhibited constitutively higher proline, total sugar, and
H2O2 contents as well as antioxidant capacity compared to the durum wheat
seeds (p < 0.05). In conclusion, the current findings suggest that the
interplay of oxidative metabolism and compatible solutes may contribute to
improving germination tolerance under water deficit and salinity conditions
in wheat.
Publisher
National Library of Serbia