Abstract
Nitrate fertilizers are common source of nitrogen (N) in nutrient solutions. Substitution of urea with nitrate could reduce this dependence. Also, nickel (Ni) is essential for activation of urease in plants fed with urea. For this aim, a factorial experiment was conducted in a completely randomized design with four replicates. Urea in five levels (0, 25, 50, 75 and 100 mg/L) and Ni in two levels (0 and 2 mg/L) were used for lettuce (Lactuca sativa cv. Siyahoo) in hydroponics. The results showed that the highest fresh and dry weight of leaves and stem were obtained in 50 mg/L urea treatment. Leaf area was reduced in treatments having more than 25 mg/L urea concentration. The highest chlorophyll index and maximal quantum yield of PS II photochemistry efficiency (Fv/Fm) were obtained in 100 and 75 mg/L urea, respectively. Total nitrogen concentration of leaves was increased significantly with increasing urea concentration; plants treated with 100 mg/L urea had the highest total nitrogen concentration. Nickel application reduced yield and physiological traits of lettuce; while it had no significant effect on total nitrogen concentration.
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Claims 8
Claim · model-written summary
Leaf fresh and dry weight were highest at 50 mg/L urea.
- Taxon
- lettuce
Lactuca sativat0 - Treatment
- 50 mg/L urea treatmente0
- Outcome
- fresh and dry weight of leavese0
- Direction
- higheste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The results showed that the highest fresh and dry weight of leaves and stem were obtained in 50 mg/L urea treatment.”
t0“lettuce”
Claim · model-written summary
Stem fresh and dry weight were highest at 50 mg/L urea.
- Taxon
- lettuceLactuca sativat0
- Treatment
- 50 mg/L urea treatmente0
- Outcome
- fresh and dry weight of leaves and steme0
- Direction
- higheste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The results showed that the highest fresh and dry weight of leaves and stem were obtained in 50 mg/L urea treatment.”
t0“lettuce”
Claim · model-written summary
Leaf area fell above 25 mg/L urea.
- Taxon
- lettuceLactuca sativat0
- Treatment
- more than 25 mg/L urea concentratione0
- Outcome
- Leaf areae0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf area was reduced in treatments having more than 25 mg/L urea concentration.”
t0“lettuce”
Claim · model-written summary
Chlorophyll index was highest at 100 mg/L urea.
- Taxon
- lettuceLactuca sativat0
- Treatment
- 100e0
- Outcome
- chlorophyll indexe0
- Direction
- higheste0
- Qualifier
- mg/L ureae0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest chlorophyll index and maximal quantum yield of PS II photochemistry efficiency (Fv/Fm) were obtained in 100 and 75 mg/L urea, respectively.”
t0“lettuce”
Claim · model-written summary
Maximal PS II quantum yield was highest at 75 mg/L urea.
- Taxon
- lettuceLactuca sativat0
- Treatment
- 75 mg/L ureae0
- Outcome
- maximal quantum yield of PS II photochemistry efficiency (Fv/Fm)e0
- Direction
- higheste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The highest chlorophyll index and maximal quantum yield of PS II photochemistry efficiency (Fv/Fm) were obtained in 100 and 75 mg/L urea, respectively.”
t0“lettuce”
Claim · model-written summary
Leaf total nitrogen rose significantly with increasing urea, peaking at 100 mg/L.
- Taxon
- lettuceLactuca sativat0
- Treatment
- increasing urea concentratione0
- Outcome
- Total nitrogen concentration of leavese0
- Direction
- increasede0
- Qualifier
- 100 mg/L ureae0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total nitrogen concentration of leaves was increased significantly with increasing urea concentration; plants treated with 100 mg/L urea had the highest total nitrogen concentration.”
t0“lettuce”
Claim · model-written summary
Nickel application reduced lettuce yield and physiological traits.
- Taxon
- lettuceLactuca sativae0
- Treatment
- Nickel applicatione0
- Outcome
- yield and physiological traitse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nickel application reduced yield and physiological traits of lettuce; while it had no significant effect on total nitrogen concentration.”
Claim · model-written summary
Nickel application had no significant effect on total nitrogen concentration.
- Taxon
- lettuceLactuca sativae0
- Treatment
- Nickel applicatione0
- Outcome
- total nitrogen concentratione0
- Direction
- no significant effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nickel application reduced yield and physiological traits of lettuce; while it had no significant effect on total nitrogen concentration.”
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