Effects of Salinity Stress on Growth and Physio-biochemical Parameters of Three Pea (Pisum sativum L.) Cultivars of Different Maturity Duration

Background: Salinity is one of the leading abiotic stresses that negatively affects the growth of many important food crops and significantly reduces the productivity and yield value.Methods: The present study was conducted to study the effects of NaCl stress on three pea (Pisum sativum) cultivars (Climax, Lina Pak and Pea-267) of different maturity level (Late, early, and mid-season flowering) under In vitro conditions. Two weeks old In vitro grown shoots of three pea cultivars were subjected to stress condition in MS medium supplemented with five levels of NaCl (0, 20, 40, 80 and 100mM NaCl) for one month and different morphological and physio-biochemical traits including length of shoot, number of leaves, shoot biomass, chlorophyll, proline and total phenolic content, total proteins and non-enzymatic antioxidant (DPPH) activities were studied.Results: The results were analyzed using different statistical approaches (ANOVA, MNOVA, PCA, correlation and regression) to identify the tolerance level of each genotype. Shoot length and shoot fresh weight were increased at 20 and 40mM in Climax, while proline content progressively increased with an increase in stress concentration in all the genotypes. Total protein content increased in cvs. Climax and Pea-267 and decreased in Lina Pak above 20mM and DPPH was increased in Climax and Pea-267 at 20 and 40mM, while in Lina Pak it showed an increase at only 20mM NaCl concentration. According to the results of MNOVA and regression analysis, significant changes occurred in biomass, proline content and DPPH values. A strong positive correlation of shoot dry weight was found with total phenolic and proline content. Maximum value of stress tolerance index was recorded for Climax.Conclusion: Biplot analysis clustered cvs. Climax and Pea-267 cultivars into tolerant group and Lina Pak in sensitive group based on the mean performance of studied parameters to NaCl stress and control treatments.