As water quality and availability decreases in many parts of the world, salinity is becoming a major challenge that reduces crop yield, even in soilless cultivation systems. Therefore, novel strategies are needed to promote plant salt tolerance in these systems. We hypothesized that the non-essential element silicon (Si) and plant-growth promoting Bacillus spp. can alleviate salt stress of cucumber (Cucumis sativus L.) grown in hydroponics. We tested this hypothesis by growing cucumber seedlings with and without salt stress (75 mM NaCl) and with and without 1.5 mM Si and an inoculum of six rhizosphere Bacillus species in a full-factorial design. Seedlings were grown in a climate room for two weeks in independent deep-water culture containers. The applied salt stress strongly reduced plant biomass, whereas Si application under salt stress resulted in a substantial increase in cucumber shoot and root biomass. This beneficial impact of Si was also observed in increased plant height, leaf area, specific leaf area, root length, specific root length, root surface area and root volume. The Bacillus species increased root dry weight, specific leaf area as well as specific root length. In seedlings grown under salt stress, Si application increased shoot and root Si concentration, whereas Cl⁻ concentration was reduced in the plant shoots. A reduction in Cl⁻ concentration of the shoots was also apparent in the Bacillus treatment. Under non-stress conditions, neither Si nor Bacillus species affected plant growth parameters. However, shoot mineral content was affected as Si application reduced shoot Cl⁻and Ca²⁺ concentrations, and inoculation with Bacillus species decreased K concentration. We conclude that Si does promote salt stress alleviation during the early growth stage of cucumber grown in deep water culture and this has implications for soilless crop production. Seed inoculation with Bacillus species showed a beneficial trend for some plant growth characteristics and nutrient status under high salinity, although not as pronounced as for Si.

随着世界许多地方的水质和可用性下降，盐分正成为降低作物产量的主要挑战，即使在无土栽培系统中也是如此。因此，需要新的策略来促进这些系统中的植物耐盐性。我们假设非必需元素硅 (Si) 和促进植物生长的芽孢杆菌属。可以减轻水培黄瓜 ( Cucumis sativus L.) 的盐胁迫。我们通过在有和没有盐胁迫 (75 mM NaCl) 和有和没有 1.5 mM Si 和六种根际芽孢杆菌接种物的情况下种植黄瓜幼苗来测试这一假设全因子设计中的物种。幼苗在独立的深水培养容器中在气候室中生长两周。施加盐胁迫强烈降低植物生物量，而在盐胁迫下施用硅导致黄瓜枝条和根生物量显着增加。在增加植物高度、叶面积、比叶面积、根长、比根长、根表面积和根体积方面也观察到了硅的这种有益影响。所述芽孢杆菌属物种增加的根干重，比叶面积以及特定的根长度。在盐胁迫下生长的幼苗中，Si 的施用增加了地上部和根部的 Si 浓度，而植物地上部中的Cl ^-浓度降低。Cl的减少^-芽的浓度在芽孢杆菌处理中也很明显。在非胁迫条件下，Si 和芽孢杆菌属物种均不影响植物生长参数。然而，由于施用硅会降低枝条 Cl ^-和 Ca ²⁺浓度，并且接种芽孢杆菌会降低 K 浓度，因此枝条矿物质含量受到影响。我们得出的结论是，在深水养殖中生长的黄瓜的早期生长阶段，Si 确实促进了盐胁迫的缓解，这对无土作物生产有影响。芽孢杆菌的种子接种 物种在高盐度下对某些植物生长特征和营养状况显示出有益的趋势，尽管不如 Si 明显。