The Effects of Salt Stress on Germination, Seedling Growth and Biochemical Responses of Tunisian Squash (Cucurbita maxima Duchesne) Germplasm

Abstract

Salt stress is considered as one of the most common abiotic stresses reducing the productivity and fruit quality of crop plants. The present study was carried out to assess the salt tolerance among 15 local squash (Cucurbita maxima Duchesne) landraces. Different salt (NaCl) concentrations of 0, 100, 200 and 300 mM were selected in order to evaluate the response of the study germplasm to salt stress based on 12 agronomic parameters and 3 biochemical traits, proline, malondialdehyde (MDA) and chlorophylls. A varied effect of the salt stress level was observed among the studied landraces based on germination potential, as well as on growth and biochemical parameters at seedling stage. Results showed that all landraces were drastically affected at high stress level with a significant variation in their stress response, indicating the existence of considerable genetic variability. Landraces “746” and “747” were the best performing cultivars across stress levels, whereas “1007”, “1008” and “1009” were the most negatively affected. Based on the tested landrace performance, four landraceswere selected and further evaluated at biochemical level, focusing on the determination of compounds that play a key role in the ability to withstand salt stress. The mean MDA content across landraces was generally increased in stressed plants, as compared to the control treatment; the increase was attributed to a peak in MDA content at specific stress levels. In particular, “746” and “1007” showed the maximum content at 100 mM NaCl, while in landrace “751”, MDA content reached its peak at 300 mM NaCl. In addition, the response of most landraces to salt stress involved an increase in free proline content, with the exception of “746”, with the maximum content being observed either at 200 mM (“748” and “751” landraces) or at 300 mM NaCl, where only “747” expressed the highest content. These findings can be extrapolated into efforts to develop more salt-tolerant squash landraces and exhaust the possibilities of using saline water or soils under changing climate conditions.

Effect of NaCl Salt Stress on Growth, Ions and Organic Solutes Contents in a Local Cultivar Kpinman of African Eggplant (Solanum macrocarpon L) in the Republic of Benin

“…These data confirmed our previous findings in the same African eggplant cultivar [11]. "The reduction of plant growth under salt stress is a common phenomenon as reported in other plant species including vegetables" [16,17,18,19]. According to [3], "the detrimental effects of salinity on plants can be osmotic in nature (reduction of water absorption by the plant after high osmotic pressure), toxic (transport and accumulation of excessive amounts of certain ions, in particular Na + in the aerial parts) or nutritional (deficiency in the absorption of certain essential ions, K + and Ca ++ in particular)".…”

Genotypic variation in tolerance to salinity in Pakistani okra (Abelmoschus esculentus L.) varieties as assessed at seed germination, seedling growth and biochemical characters

“…In general, the data presented in (table 2 and 3), there is a disparity in the studied characters associated with seed germination and seedling growth of okra varieties at any level of stress, the overall trend is that salt stress differentially affects all studied characters, with the effects being in maximum cases proportional to the stress level applied. These results are dependable with earlier studies regarding the effects of salt stress on the seed germination of lettuce [40], rice [41], chickpea [42] and wheat [43]. Similar results of germination inhibition were also highlighted by [44][45][46] in other plants.…”

“…Similar results of germination inhibition were also highlighted by [44][45][46] in other plants. Our results indicate that a balance increasing severity of effects depending on salt concentration, thus proving the earlier results that the variable stress levels differentially affect germination and seedling growth in different plants species, sugar beet and cabbage [47], soybean [40] and lentil [48]. All the studied varieties in our investigation were badly affected by salt stress, particularly at stress level 100 mM NaCl.…”

Sensitivity of different flax (Linum usitatissimum L.) genotypes to salinity determined by GE biplot

“…Salinity in the growing environment is one of the limiting factors in crop production. The salt ratio in the environment alters numerous biochemical and physiological events in plants ( Tarchoun et al, 2022 ). Plant breeding efforts are highly affected by salinity in the environment, especially at different developmental stages of crop plants.…”

“…High salt concentration in the soil inhibits seed germination or induces dormancy at low levels ( Farooq et al, 2015 ). Salinity negatively seed germination and disrupts several processes at physiological and metabolic levels, including changes in the enzymatic activities ( Tarchoun et al, 2022 ). Flax is a moderately salinity-tolerant plant and a yield decrease of 10 %, 25 % and 50 % has been reported under 2.5, 3.8 and 5.9 mM salinity, respectively ( Dubey et al, 2020 ).…”