Abstract
Abstract The efficient use of N for crop production is important because N is normally the most expensive fertilizer input. Past research has suggested that Ca++ can be used to stimulate NH4+ absorption by plants. The importance of plant growth stage in relation to this phenomenon has not been examined previously. The objectives of this study were to examine Ca++ ‐ stimulated NH4 + absorption and to examine the effect of Ca++ concentration on N content and growth in plant tops, bulbs and roots at different growth stages. Ammonium absorption experiments were conducted in the greenhouse in 4‐L pots containing 3.5 kg of calcareous Gila sandy loam (Typic Torrifluvents) (CEC <1 cMol kg−1). Plants (Radish, Raphanus sativas L., and onion, Allium cepa L.) were grown with a uniform nutrient solution (1/2 strength nutrient solution, all N as NO3) to the desired growth stage at which time the soil was leached with deionized water. Afterwards, the soils were fertilized with 1/2 strength nutrient solutions (5 mol m−3 NH4) with Ca++: NH4 + molar ratios of 0, 0.25, 0.50, 1.00, and 2.00 for a period of 30 h. As Ca++ concentration increased, NH4 + absorption and plant growth increases were greatest with young seedlings. In the intermediate and mature growth stages, Ca++ stimulated 15NH4 + absorption was less rapid than in the earlier growth stages but frequently exhibited a different response (i.e., altered metabolite translocation) to the added Ca++ ‐ concentration. However, at the intermediate and mature growth stages significantly increased N contents and plant growth also were noted in most cases. The Ca++ ‐ increased N content in leaves and bulbs of the older plants had much less 15N suggesting that the newly absorbed 15NH4 + was being deposited in the roots replacing older N forms that were then translocated to the bulbs or leaves. Thus, increasing Ca++ appeared to have anadditional function of increasing the mobility of metabolites (dry matter) from the roots. Since more above‐ground plant products were produced with the same amount of N, plant N use efficiency was increased.
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Claims 7
Claim · model-written summary
Increasing calcium had the greatest ammonium absorption and growth responses in young seedlings.
- Taxon
- radish and onion
Raphanus sativus
Allium cepat0 - Organ / stage
- young seedlingse0
- Treatment
- Ca++ concentratione0
- Outcome
- NH4 + absorption and plant growthe0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“As Ca++ concentration increased, NH4 + absorption and plant growth increases were greatest with young seedlings.”
t0“radish and onion”
Claim · model-written summary
Calcium-stimulated ammonium absorption was less rapid at intermediate and mature stages.
- Taxon
- radish and onionRaphanus sativusAllium cepat0
- Organ / stage
- intermediate and mature growth stagese0
- Outcome
- 15NH4 + absorptione0
- Direction
- less rapide0
- Comparator
- earlier growth stagese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In the intermediate and mature growth stages, Ca++ stimulated 15NH4 + absorption was less rapid than in the earlier growth stages”
t0“radish and onion”
Claim · model-written summary
Calcium significantly raised nitrogen contents in most intermediate and mature plants.
- Taxon
- radish and onionRaphanus sativusAllium cepat0
- Treatment
- Ca++e1
- Outcome
- N contentse0
- Direction
- increasede0
- Qualifier
- in most casese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“at the intermediate and mature growth stages significantly increased N contents and plant growth also were noted in most cases.”
t0“radish and onion”
e1“As Ca++ concentration increased, NH4 + absorption and plant growth increases were greatest with young seedlings.”
Claim · model-written summary
Calcium significantly increased growth in most intermediate and mature plants.
- Taxon
- radish and onionRaphanus sativusAllium cepat0
- Treatment
- Ca++e1
- Outcome
- plant growthe0
- Direction
- increasede0
- Qualifier
- in most casese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“at the intermediate and mature growth stages significantly increased N contents and plant growth also were noted in most cases.”
t0“radish and onion”
e1“As Ca++ concentration increased, NH4 + absorption and plant growth increases were greatest with young seedlings.”
Claim · model-written summary
In older plants, calcium-increased leaf and bulb nitrogen contained much less 15N.
- Taxon
- radish and onionRaphanus sativusAllium cepat0
- Organ / stage
- leaves and bulbse0
- Outcome
- 15Ne0
- Direction
- much lesse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Ca++ ‐ increased N content in leaves and bulbs of the older plants had much less 15N”
t0“radish and onion”
Claim · model-written summary
Calcium appeared to increase metabolite mobility from roots.
- Taxon
- radish and onionRaphanus sativusAllium cepat0
- Treatment
- Ca++e0
- Outcome
- mobility of metabolites (dry matter)e0
- Direction
- increasinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increasing Ca++ appeared to have anadditional function of increasing the mobility of metabolites (dry matter) from the roots.”
t0“radish and onion”
Claim · model-written summary
Plant nitrogen use efficiency increased.
- Taxon
- radish and onionRaphanus sativusAllium cepat0
- Outcome
- plant N use efficiencye0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Since more above‐ground plant products were produced with the same amount of N, plant N use efficiency was increased.”
t0“radish and onion”
The same questions in other papers
calcium atom · nutrient: content · Raphanus sativus (radish)Results agree
1 paper in the same direction as this paper
- positive
calcium atom · nutrient: content · Allium cepa (onion)Results agree
2 papers in the same direction as this paper
- positive
- positive
calcium atom · growth · Allium cepa (onion)Results agree
3 papers in the same direction as this paper
- positive
- positive
- positive
calcium atom · growth · Raphanus sativus (radish)Results agree
6 papers in the same direction as this paper
- positive
- positive
- positive
3 papers more in this group
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.