Alleviation of Salt Stress by Plant Growth-Promoting Bacteria in Hydroponic Leaf Lettuce
Mediterranean areas with intensive agriculture are characterized by high salinity of groundwater. The use of this water in hydroponic cultivations can lead to nutrient solutions with an electrical conductivity that overcomes the tolerance threshold of many vegetable species. Plant growth-promoting r...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-10-01
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| Series: | Agronomy |
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| Online Access: | https://www.mdpi.com/2073-4395/10/10/1523 |
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| author | Alessandra Moncada Filippo Vetrano Alessandro Miceli |
| author_facet | Alessandra Moncada Filippo Vetrano Alessandro Miceli |
| author_sort | Alessandra Moncada |
| collection | DOAJ |
| description | Mediterranean areas with intensive agriculture are characterized by high salinity of groundwater. The use of this water in hydroponic cultivations can lead to nutrient solutions with an electrical conductivity that overcomes the tolerance threshold of many vegetable species. Plant growth-promoting rhizobacteria (PGPR) were shown to minimize salt stress on several vegetable crops but the studies on the application of PGPR on leafy vegetables grown in hydroponics are rather limited and have not been used under salt stress conditions. This study aimed to evaluate the use of plant growth-promoting bacteria to increase the salt tolerance of leaf lettuce grown in autumn and spring in a floating system, by adding a bacterial biostimulant (1.5 g L<sup>−1</sup> of TNC Bactorr<sup>S13</sup> a commercial biostimulant containing 1.3 × 10<sup>8</sup> CFU g<sup>−1</sup> of <i>Bacillus spp.</i>) to mineral nutrient solutions (MNS) with two salinity levels (0 and 20 mM NaCl). Leaf lettuce plants showed a significant reduction of growth and yield under salt stress, determined by the reduction of biomass, leaf number, and leaf area. Plants showed to be more tolerant to salinity in autumn than in spring. The inhibition of lettuce plant growth due to salt stress was significantly alleviated by the addition of the bacterial biostimulant to the MNS, which had a positive effect on plant growth and fresh and dry biomass accumulation of the unstressed lettuce in both cultivation seasons, and maintained this positive effect in brackish MNS, with similar or even significantly higher values of morphologic, physiologic, and yield parameters than those recorded in control unstressed plants. |
| first_indexed | 2024-03-10T15:49:08Z |
| format | Article |
| id | doaj.art-bf4bb6a4e2504506ae58626f6e4472be |
| institution | Directory Open Access Journal |
| issn | 2073-4395 |
| language | English |
| last_indexed | 2024-03-10T15:49:08Z |
| publishDate | 2020-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Agronomy |
| spelling | doaj.art-bf4bb6a4e2504506ae58626f6e4472be2023-11-20T16:14:19ZengMDPI AGAgronomy2073-43952020-10-011010152310.3390/agronomy10101523Alleviation of Salt Stress by Plant Growth-Promoting Bacteria in Hydroponic Leaf LettuceAlessandra Moncada0Filippo Vetrano1Alessandro Miceli2Department of Agricultural, Food and Forestry Sciences, University of Palermo, Viale delle Scienze 4, 90128 Palermo, ItalyDepartment of Agricultural, Food and Forestry Sciences, University of Palermo, Viale delle Scienze 4, 90128 Palermo, ItalyDepartment of Agricultural, Food and Forestry Sciences, University of Palermo, Viale delle Scienze 4, 90128 Palermo, ItalyMediterranean areas with intensive agriculture are characterized by high salinity of groundwater. The use of this water in hydroponic cultivations can lead to nutrient solutions with an electrical conductivity that overcomes the tolerance threshold of many vegetable species. Plant growth-promoting rhizobacteria (PGPR) were shown to minimize salt stress on several vegetable crops but the studies on the application of PGPR on leafy vegetables grown in hydroponics are rather limited and have not been used under salt stress conditions. This study aimed to evaluate the use of plant growth-promoting bacteria to increase the salt tolerance of leaf lettuce grown in autumn and spring in a floating system, by adding a bacterial biostimulant (1.5 g L<sup>−1</sup> of TNC Bactorr<sup>S13</sup> a commercial biostimulant containing 1.3 × 10<sup>8</sup> CFU g<sup>−1</sup> of <i>Bacillus spp.</i>) to mineral nutrient solutions (MNS) with two salinity levels (0 and 20 mM NaCl). Leaf lettuce plants showed a significant reduction of growth and yield under salt stress, determined by the reduction of biomass, leaf number, and leaf area. Plants showed to be more tolerant to salinity in autumn than in spring. The inhibition of lettuce plant growth due to salt stress was significantly alleviated by the addition of the bacterial biostimulant to the MNS, which had a positive effect on plant growth and fresh and dry biomass accumulation of the unstressed lettuce in both cultivation seasons, and maintained this positive effect in brackish MNS, with similar or even significantly higher values of morphologic, physiologic, and yield parameters than those recorded in control unstressed plants.https://www.mdpi.com/2073-4395/10/10/1523saline waterleafy vegetables<i>Lactuca sativa</i> L. var. <i>Crispa</i>floating systemnutrient solutionbacterial biostimulant |
| spellingShingle | Alessandra Moncada Filippo Vetrano Alessandro Miceli Alleviation of Salt Stress by Plant Growth-Promoting Bacteria in Hydroponic Leaf Lettuce Agronomy saline water leafy vegetables <i>Lactuca sativa</i> L. var. <i>Crispa</i> floating system nutrient solution bacterial biostimulant |
| title | Alleviation of Salt Stress by Plant Growth-Promoting Bacteria in Hydroponic Leaf Lettuce |
| title_full | Alleviation of Salt Stress by Plant Growth-Promoting Bacteria in Hydroponic Leaf Lettuce |
| title_fullStr | Alleviation of Salt Stress by Plant Growth-Promoting Bacteria in Hydroponic Leaf Lettuce |
| title_full_unstemmed | Alleviation of Salt Stress by Plant Growth-Promoting Bacteria in Hydroponic Leaf Lettuce |
| title_short | Alleviation of Salt Stress by Plant Growth-Promoting Bacteria in Hydroponic Leaf Lettuce |
| title_sort | alleviation of salt stress by plant growth promoting bacteria in hydroponic leaf lettuce |
| topic | saline water leafy vegetables <i>Lactuca sativa</i> L. var. <i>Crispa</i> floating system nutrient solution bacterial biostimulant |
| url | https://www.mdpi.com/2073-4395/10/10/1523 |
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