The Relationship between the Antioxidant System and Proline Metabolism in the Leaves of Cucumber Plants Acclimated to Salt Stress

Abstract

The study examines the effect of acclimation on the antioxidant system and proline metabolism in cucumber leaves subjected to 100 and 150 NaCl stress. The levels of protein carbonyl group, thiobarbituric acid reactive substances, α-tocopherol, and activity of ascorbate and glutathione peroxidases, catalase, glutathione S-transferase, pyrroline-5-carboxylate: synthetase and reductase as well as proline dehydrogenase were determined after 24 and 72 h periods of salt stress in the acclimated and non-acclimated plants. Although both groups of plants showed high α-tocopherol levels, in acclimated plants was observed higher constitutive concentration of these compounds as well as after salt treatment. Furthermore, the activity of enzymatic antioxidants grew in response to salt stress, mainly in the acclimated plants. In the acclimated plants, protein carbonyl group levels collapsed on a constitutive level and in response to salt stress. Although both groups of plants showed a decrease in proline dehydrogenase activity, they differed with regard to the range and time. Differences in response to salt stress between the acclimated and non-acclimated plants may suggest a relationship between increased tolerance in acclimated plants and raised activity of antioxidant enzymes, high-level of α-tocopherol as well, as decrease enzyme activity incorporates in proline catabolism.

Comparative Study between Exogenously Applied Plant Growth Hormones versus Metabolites of Microbial Endophytes as Plant Growth-Promoting for Phaseolus vulgaris L.

“…Extracellular enzymes are the byproducts of microbial cell formation, and they play a role in a variety of biological and environmental processes outside of cells. Plants use antioxidant enzymes such as catalase and peroxidase to ameliorate the toxic substances such as reactive oxygen species (ROS), biotic, and abiotic stresses [ 90 ].…”

Proline Concentration and Its Metabolism Are Regulated in a Leaf Age Dependent Manner But Not by Abscisic Acid in Pea Plants Exposed to Cadmium Stress

“…Increased proline accumulation is one of the defense mechanisms that plants have developed to counteract the harmful effects of adverse environmental condition stresses such as drought, salinity, and hypoxia [9,11,62,63]. Under Cd stress, however, the changes in proline concentration are often contradictory, especially in the leaves [33][34][35][36][37]64].…”

Current challenges in plant breeding to achieve zero hunger and overcome biotic and abiotic stresses induced by the global climate changes: A review

“…Also, the application of applying diethyl aminoethyl hexanoate, will increase plant resistance to abiotic stress, like cold [43,44] and salinity resistance [45]. And, using the proline aminoacid during plant acclimatization has shown to increase tolerance to salt stress [46] and to lower water condition [47].…”

“…Another way to increase resistance is by using microbial biotechnology to enhance plant nutrition and/or promote biocontrol against pathogens [41,42], applying diethyl aminoethyl hexanoate to achieve resistance to abiotic stress [43][44][45], and use the prolineto increase salt tolerance [46] and low water condition [47].…”