Physiological and biochemical responses of seedlings of six contrasting barley (Hordeum vulgare L.) cultivars grown under salt-stressed conditions

Abstract

Salinity stress affects plant growth and development and underlying metabolisms. To mitigate the effects of the stress, plants responded by changing their physiological and biochemical activities and withstand the stress. The present study aimed to determine barley's (Hordeum vulgare L.) physiological and biochemical response to salinity stress conditions for 7 days and 14 days. Six barley cultivars (Alfa93, DWRB73, DL88, NB1, NB3, NDB1173) were grown under controlled conditions, and different level of salinity stress was applied. In addition, seedling growth, physiological and biochemical parameters, plant leaves RWC, and electrolyte leakage were analyzed. The overall seedling growth, RWC, and electrolyte leakage in salt susceptible lines Alfa93 and DWRB73 were low than the salt-tolerant barley lines (DL88, NB1, NB3, and NDB1173). Electrolyte leakage was 26.0 and 20.6% in Alfa93 and DWRB73, whereas it was 17.6, 14.6, 15.3, and 10.4% in DL88, NB1, NB3, and NDB1173, respectively at 300 mM salinity stress. The loss of photosynthetic pigments under salt stress was high in susceptible lines, salinity treated (300 mM NaCl) Alfa93 plants exhibit 49.5% and 59.5% of Chl-a than control plants after 7 and 14 days of treatment, respectively. However, at 300 mM stress level, NB1 (ST) showed less Chl-a loss after 7 days, whereas NDB1173 showed less reduction in Chl-a after 14 days. Antioxidant enzymes such as SOD, POX, CAT, and APX activities in susceptible line Alfa93 and DWRB73 were lower than tolerant lines. PCA analysis demonstrated a positive correlation between antioxidant enzyme activities and genotypes under salinity stress. PCA analysis described DL88 as the most tolerant, and DWRB73 was the most salt susceptible genotype among the studied barley genotypes. The present findings suggest that barley cultivars' physiological and biochemical activities under salinity stress conditions may be used to screen salt-tolerant crops.