Abstract
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−1 of TNC BactorrS13 a commercial biostimulant containing 1.3 × 108 CFU g−1 of Bacillus spp.) 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.
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Claims 5
Claim · model-written summary
Salt stress reduced lettuce biomass, leaf number and leaf area.
- Taxon
- Leaf lettucee0
- Treatment
- salt stresse0
- Outcome
- biomass, leaf number, and leaf areae0
- Direction
- reductione0
Not reportedComparator
Verbatim
e0“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.”
Claim · model-written summary
Lettuce tolerated salinity better in autumn than spring.
Not reportedTaxon
Verbatim
e0“Plants showed to be more tolerant to salinity in autumn than in spring.”
Claim · model-written summary
Bacterial biostimulant alleviated salt inhibition of lettuce growth.
- Taxon
- lettuce
Lactuca sativae0 - Treatment
- addition of the bacterial biostimulant to the MNSe0
- Outcome
- inhibition of lettuce plant growthe0
- Direction
- alleviatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The inhibition of lettuce plant growth due to salt stress was significantly alleviated by the addition of the bacterial biostimulant to the MNS”
Claim · model-written summary
Biostimulant improved growth and fresh and dry biomass of unstressed lettuce in both seasons.
- Taxon
- lettuceLactuca sativae0
- Outcome
- plant growth and fresh and dry biomass accumulatione0
- Direction
- positive effecte0
- Qualifier
- both cultivation seasonse0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“positive effect on plant growth and fresh and dry biomass accumulation of the unstressed lettuce in both cultivation seasons”
Claim · model-written summary
Biostimulant maintained positive effects in brackish solution, with parameters similar to or higher than unstressed controls.
- Treatment
- brackish MNSe0
- Outcome
- morphologic, physiologic, and yield parameterse0
- Direction
- similar or even significantly highere0
- Comparator
- control unstressed plantse0
Not reportedTaxon
Verbatim
e0“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.”
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mineral nutrient · yield · Lactuca sativa (garden lettuce)Results agree
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salinity · growth · Lactuca sativa (garden lettuce)Results differ
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- no effect
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See all 7 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.