Tarchoun Neji, Saadaoui Wassim, Mezghani Najla, Pavli Ourania I, Falleh Hanen, Petropoulos Spyridon A
High Agronomic Institute of Chott Mariem, University of Sousse, Sousse 4042, Tunisia.
National Gene Bank, Boulevard du Leader Yasser Arafat, ZI Charguia 1, Tunis 1080, Tunisia.
Plants (Basel). 2022 Mar 17;11(6):800. doi: 10.3390/plants11060800.
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 ( 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.
盐胁迫被认为是降低作物生产力和果实品质的最常见非生物胁迫之一。本研究旨在评估15个当地南瓜（西葫芦）地方品种的耐盐性。选择了0、100、200和300 mM的不同盐（氯化钠）浓度，以便根据12个农艺参数和3个生化性状（脯氨酸、丙二醛（MDA）和叶绿素）评估研究种质对盐胁迫的响应。基于发芽势以及苗期的生长和生化参数，在所研究的地方品种中观察到盐胁迫水平的不同影响。结果表明，所有地方品种在高胁迫水平下均受到严重影响，其胁迫响应存在显著差异，表明存在相当大的遗传变异性。地方品种“746”和“747”在各胁迫水平下表现最佳，而“1007”、“1008”和“1009”受到的负面影响最大。根据测试的地方品种表现，选择了四个地方品种并在生化水平上进一步评估，重点是确定在耐盐能力中起关键作用的化合物。与对照处理相比，受胁迫植株中各地方品种的平均MDA含量普遍增加；这种增加归因于特定胁迫水平下MDA含量的峰值。特别是，“746”和“1007”在100 mM氯化钠时显示出最高含量，而在地方品种“751”中，MDA含量在300 mM氯化钠时达到峰值。此外，除“746”外，大多数地方品种对盐胁迫的响应涉及游离脯氨酸含量的增加，最高含量出现在200 mM（“748”和“751”地方品种）或300 mM氯化钠时，只有“747”在该浓度下表现出最高含量。这些发现可以推广到培育更耐盐的南瓜地方品种的努力中，并在气候变化条件下充分利用盐水或盐碱地的可能性。
