Comparative Studies on the Physiological and Biochemical Responses to Salt Stress of Eggplant (Solanum melongena) and Its Rootstock S. torvum

Abstract

This study investigated the physiological and biochemical responses to salinity stress of Solanum melongena and its wild relative, Solanum torvum, commonly used as eggplant rootstock. Young plants of both species were watered during 25 days with NaCl aqueous solutions at the following four final concentrations: 0 (for the controls), 100, 200, and 300 mM. Plant growth parameters, photosynthetic pigments content, monovalent ion concentrations in roots and leaves, leaf levels of osmolytes (proline and total soluble sugars), oxidative stress markers (MDA and H2O2), non-enzymatic antioxidants (total phenolic compounds and total flavonoids), and enzymatic antioxidant activities (superoxide dismutase, catalase, glutathione reductase) were determined after the stress treatments. Salt-induced growth reduction was more significant in S. melongena than in S. torvum, especially at high salt concentrations, indicating a (slightly) higher salt tolerance of the wild species. The mechanisms of tolerance of S. torvum were partly based on the active transport of toxic ions to the leaves at high external salinity and, presumably, a better capacity to store them in the vacuoles, as well as on the accumulation of proline to higher concentrations than in the cultivated eggplant. MDA and H2O2 contents did not vary in response to the salt treatments in S. torvum. However, in S. melongena, MDA content increased by 78% when 300 mM NaCl was applied. No activation of antioxidant mechanisms, accumulation of antioxidant compounds, or increase in the specific activity of antioxidant enzymes in any of the studied species was induced by salinity. The relatively high salt tolerance of S. torvum supports its use as rootstock for eggplant cultivation in salinized soils and as a possible source of salt-tolerance genes for the genetic improvement of cultivated eggplant.

Grafting Improves Fruit Yield of Cucumber Plants Grown under Combined Heat and Soil Salinity Stresses

“…Apart from the evaluation of growth and development traits, several antioxidant enzymes, such as catalase and peroxidase, play a main role in reducing oxidative damage caused by stress [31]. In addition, osmolytes such as proline are known to be involved in maintaining the osmotic balance under salinity stress [32].…”

Sugarcane Plant Growth and Physiological Responses to Soil Salinity during Tillering and Stalk Elongation

“…However, plant tolerances to saline vary widely from soil to soil and from salt type to salt type [5] as well as differences among crop species and growth stages. Crop species show the big differences in tolerance to salinity [5][6][7].…”

The Role of Plant Growth Promoting Rhizosphere Microbiome as Alternative Biofertilizer in Boosting Solanum melongena L. Adaptation to Salinity Stress

“…In the current study, under salinity stress Na + ions were largely translocated to the shoot; this was revealed from the relatively higher TF compared to that of untreated plants, while application of selected bioinoculum to salt-stressed eggplants relatively decreased the TF of Na + ions with respect to saline pots. The Solanum trovum resistance mechanism to salinity was moderately based on the active transport of toxic ions to the leaves and, probably, a better capacity to store them in the vacuoles [ 44 , 45 ].…”

“…Proline content was increased in two genotypes (Barcelone and Threa) of S. melongena L. under salinity stress [ 53 ]. Similarly, leaf proline levels increased significantly in S. melongena and S. insanum in response to different salt stress treatments, moreover it is suggested that S. insanum is more tolerant to salinity stress due to its capacity to accumulate proline and to a lesser extent Na + and Cl − [ 44 ].…”