Abstract
An optimized nitrogen (N) fertilization may have a positive effect on leafy vegetables by increasing growth, yield and nutrient content of plants. Nevertheless, crop performance must be coupled with an increase in Nitrogen Use Efficiency (NUE) in order to limit external N inputs and to avoid N surpluses associated with environmental and health problems. The aim of the current study was to assess the effects of a legume-derived plant hydrolysates (LDPH; Trainer®) and N fertilization levels (0, 2.25 and 4.5 g N m−2 for spinach and 0, 2.5 and 5.0 g N m−2 for lamb’s lettuce; N0%, N50%, N100%, respectively) on agronomical, biochemical, qualitative responses and NUE of these two important greenhouse leafy vegetables. Spinach and lamb’s lettuce were sprayed four times during the growing period (at a concentration of 4 mL L−1 of LDPH). In baby spinach, the LDPH application elicited a significant increase at the three levels of N fertilization: +16.8%, +14.2%, and 39.4% at 0, 2.25 and 4.5 g N m−2, respectively. Interestingly, in lamb’s lettuce, the N50% plants treated with LDPH reached similar values of marketable yield in comparison to treated and non-treated plants under N100% conditions. The presumed mechanism involved in the enhancement of yield response in the two leafy greens could be associated to a better activity of the photosystem II (higher SPAD index), biochemical (higher content of chlorophyll a, b and total) and leaf nitrate status. The foliar application of LDPH produced a major fortification in lipophilic and hydrophilic antioxidant activities (+11.6 and 6.3% for spinach and lamb’s lettuce, respectively). The biostimulant application also improved N-use efficiency and N-uptake efficiency compared to untreated plants: +17.8% and +18.8%, and +50% and +73.3%, for spinach and lamb’s lettuce, respectively.
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Claims 13
Claim · model-written summary
LDPH increased baby spinach yield by 16.8% at 0 g N m−2.
- Taxon
- baby spinache0
- Treatment
- LDPH applicatione0
- Outcome
- increasee0
- Direction
- increasee0
- Value
- +16.8%e0
- Qualifier
- 0e0
Not reportedComparator
Verbatim
e0“In baby spinach, the LDPH application elicited a significant increase at the three levels of N fertilization: +16.8%, +14.2%, and 39.4% at 0, 2.25 and 4.5 g N m−2, respectively.”
Claim · model-written summary
LDPH increased baby spinach yield by 14.2% at 2.25 g N m−2.
- Taxon
- baby spinache0
- Treatment
- LDPH applicatione0
- Outcome
- increasee0
- Direction
- increasee0
- Value
- +14.2%e0
- Qualifier
- 2.25e0
Not reportedComparator
Verbatim
e0“In baby spinach, the LDPH application elicited a significant increase at the three levels of N fertilization: +16.8%, +14.2%, and 39.4% at 0, 2.25 and 4.5 g N m−2, respectively.”
Claim · model-written summary
LDPH increased baby spinach yield by 39.4% at 4.5 g N m−2.
- Taxon
- baby spinache0
- Treatment
- LDPH applicatione0
- Outcome
- increasee0
- Direction
- increasee0
- Value
- 39.4%e0
- Qualifier
- 4.5 g N m−2e0
Not reportedComparator
Verbatim
e0“In baby spinach, the LDPH application elicited a significant increase at the three levels of N fertilization: +16.8%, +14.2%, and 39.4% at 0, 2.25 and 4.5 g N m−2, respectively.”
Claim · model-written summary
LDPH-treated lamb’s lettuce at N50% had marketable yield similar to plants at N100%.
Verbatim
e0“in lamb’s lettuce, the N50% plants treated with LDPH reached similar values of marketable yield in comparison to treated and non-treated plants under N100% conditions.”
Claim · model-written summary
The authors suggested higher photosystem II activity may contribute to yield enhancement.
Verbatim
e0“The presumed mechanism involved in the enhancement of yield response in the two leafy greens could be associated to a better activity of the photosystem II (higher SPAD index), biochemical (higher content of chlorophyll a, b and total) and leaf nitrate status.”
Claim · model-written summary
The authors suggested higher chlorophyll content may contribute to yield enhancement.
Verbatim
e0“The presumed mechanism involved in the enhancement of yield response in the two leafy greens could be associated to a better activity of the photosystem II (higher SPAD index), biochemical (higher content of chlorophyll a, b and total) and leaf nitrate status.”
Claim · model-written summary
The authors suggested leaf nitrate status may contribute to yield enhancement.
Verbatim
e0“The presumed mechanism involved in the enhancement of yield response in the two leafy greens could be associated to a better activity of the photosystem II (higher SPAD index), biochemical (higher content of chlorophyll a, b and total) and leaf nitrate status.”
Claim · model-written summary
LDPH increased antioxidant activity in spinach by 11.6%.
- Taxon
- spinach
Spinacia oleraceae0 - Treatment
- foliar application of LDPHe0
- Outcome
- lipophilic and hydrophilic antioxidant activitiese0
- Direction
- fortificatione0
- Value
- +11.6e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The foliar application of LDPH produced a major fortification in lipophilic and hydrophilic antioxidant activities (+11.6 and 6.3% for spinach and lamb’s lettuce, respectively).”
Claim · model-written summary
LDPH increased antioxidant activity in lamb’s lettuce by 6.3%.
- Taxon
- lamb’s lettucee0
- Treatment
- foliar application of LDPHe0
- Outcome
- lipophilic and hydrophilic antioxidant activitiese0
- Direction
- fortificatione0
- Value
- 6.3%e0
Not reportedComparator
Verbatim
e0“The foliar application of LDPH produced a major fortification in lipophilic and hydrophilic antioxidant activities (+11.6 and 6.3% for spinach and lamb’s lettuce, respectively).”
Claim · model-written summary
LDPH increased spinach N-use efficiency by 17.8%.
- Taxon
- spinachSpinacia oleraceae0
- Treatment
- biostimulant applicatione0
- Outcome
- N-use efficiencye0
- Direction
- improvede0
- Value
- +17.8%e0
- Comparator
- untreated plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The biostimulant application also improved N-use efficiency and N-uptake efficiency compared to untreated plants: +17.8% and +18.8%, and +50% and +73.3%, for spinach and lamb’s lettuce, respectively.”
Claim · model-written summary
LDPH increased spinach N-uptake efficiency by 18.8%.
- Taxon
- spinachSpinacia oleraceae0
- Treatment
- biostimulant applicatione0
- Outcome
- N-uptake efficiencye0
- Direction
- improvede0
- Value
- +18.8%e0
- Comparator
- untreated plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The biostimulant application also improved N-use efficiency and N-uptake efficiency compared to untreated plants: +17.8% and +18.8%, and +50% and +73.3%, for spinach and lamb’s lettuce, respectively.”
Claim · model-written summary
LDPH increased lamb’s lettuce N-use efficiency by 50%.
Verbatim
e0“The biostimulant application also improved N-use efficiency and N-uptake efficiency compared to untreated plants: +17.8% and +18.8%, and +50% and +73.3%, for spinach and lamb’s lettuce, respectively.”
Claim · model-written summary
LDPH increased lamb’s lettuce N-uptake efficiency by 73.3%.
Verbatim
e0“The biostimulant application also improved N-use efficiency and N-uptake efficiency compared to untreated plants: +17.8% and +18.8%, and +50% and +73.3%, for spinach and lamb’s lettuce, respectively.”
The same questions in other papers
application · molecular: metabolites · Spinacia oleracea (spinach)Positive and negative results
13 papers in the same direction as this paper · 3 in the opposite direction
- negative
- negative
- no effect
13 papers more in this group
See all 17 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.