Abstract
Phosphorus (P) and potassium (K) impact alfalfa ( Medicago sativa L.) performance, but how these nutrients alter taproot physiology during fall acclimation and subsequent growth in spring is unclear. Our objectives were to: (1) determine seasonal patterns for taproot P and K concentrations during fall acclimation and during initial shoot growth in spring; (2) determine how P and K nutrition impacts accumulation of taproot C and N reserves during fall and their subsequent use when shoot growth resumes in spring; and (3) assess how addition of P and K fertilizer impacts survival and shoot growth in spring. Two P (0 and 75 kg ha −1 ) and two K (0 and 400 kg ha −1 ) treatments were applied and taproots were sampled between September and December, and again from March to May over 2 years. Concentrations of taproot sugar, starch, buffer-soluble protein, amino-N, and RNA pools were determined. While P and K fertilizer application increased taproot P and K concentrations two- to three-fold, concentrations of P and K in taproots over time did not change markedly during cold acclimation in fall, however, taproot P declined in spring as plant growth resumed. Compared to the 0K-0P treatment, taproots of plants fertilized with 400K-75P had higher starch, protein, amino-N, and RNA, but reduced sugar concentrations in fall. Concentrations of all these pools, except starch, declined during the initial 2 weeks of sampling beginning in late March as shoot growth resumed in spring. Herbage yield in May was highest for the 400K-75P treatment and least for the 0K-0P treatment, differences that were associated with variation in mass shoot −1 and not shoots m −2 . High yield of the 400K-75P plants in May was consistently associated with greater concentrations and use of amino-N, soluble protein, and RNA pools in taproots, and not with accumulation and use of starch and sugar pools. Understanding factors leading to the accumulation of taproot N reserves and RNA during cold acclimation in fall and their use during the initial growth in spring should enhance efforts to improve alfalfa growth and herbage yield in spring.
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Claims 11
Claim · model-written summary
P and K fertilizer increased taproot P and K concentrations two- to three-fold.
- Taxon
- alfalfa ( Medicago sativa L.)
Medicago sativat0 - Treatment
- P and K fertilizer applicatione0
- Outcome
- taproot P and K concentrationse0
- Direction
- increasede0
- Value
- two- to three-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“While P and K fertilizer application increased taproot P and K concentrations two- to three-fold, concentrations of P and K in taproots over time did not change markedly during cold acclimation in fall, however, taproot P declined in spring as plant growth resumed.”
t0“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
Taproot P and K concentrations did not change markedly during fall cold acclimation.
- Taxon
- alfalfa ( Medicago sativa L.)Medicago sativat0
- Outcome
- concentrations of P and K in taprootse0
- Direction
- did not change markedlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“concentrations of P and K in taproots over time did not change markedly during cold acclimation in fall”
t0“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
Taproot P declined during resumed spring growth.
- Taxon
- alfalfa ( Medicago sativa L.)Medicago sativat0
- Outcome
- taproot Pe0
- Direction
- declinede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“taproot P declined in spring as plant growth resumed”
t0“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
The 400K-75P treatment increased taproot starch, protein and amino-N versus 0K-0P in fall.
- Taxon
- alfalfa ( Medicago sativa L.)Medicago sativat0
- Treatment
- 400K-75Pe0
- Outcome
- starch, protein, amino-Ne0
- Direction
- highere0
- Comparator
- 0K-0P treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to the 0K-0P treatment, taproots of plants fertilized with 400K-75P had higher starch, protein, amino-N, and RNA, but reduced sugar concentrations in fall.”
t0“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
The 400K-75P treatment increased taproot RNA versus 0K-0P in fall.
- Taxon
- alfalfa ( Medicago sativa L.)Medicago sativat0
- Treatment
- 400K-75Pe0
- Outcome
- RNAe0
- Direction
- highere0
- Comparator
- 0K-0P treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to the 0K-0P treatment, taproots of plants fertilized with 400K-75P had higher starch, protein, amino-N, and RNA, but reduced sugar concentrations in fall.”
t0“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
The 400K-75P treatment reduced taproot sugar versus 0K-0P in fall.
- Taxon
- alfalfa ( Medicago sativa L.)Medicago sativat0
- Treatment
- 400K-75Pe0
- Outcome
- sugar concentrationse0
- Direction
- reducede0
- Comparator
- 0K-0P treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to the 0K-0P treatment, taproots of plants fertilized with 400K-75P had higher starch, protein, amino-N, and RNA, but reduced sugar concentrations in fall.”
t0“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
Taproot sugar, protein and amino-N pools declined during initial spring shoot growth.
- Taxon
- alfalfa ( Medicago sativa L.)Medicago sativat0
- Outcome
- all these pools, except starche0
- Direction
- declinede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Concentrations of all these pools, except starch, declined during the initial 2 weeks of sampling beginning in late March as shoot growth resumed in spring.”
t0“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
May herbage yield was highest with 400K-75P and lowest with 0K-0P.
- Taxon
- alfalfa ( Medicago sativa L.)Medicago sativat0
- Treatment
- 400K-75P treatmente0
- Outcome
- Herbage yielde0
- Direction
- higheste0
- Comparator
- 0K-0P treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Herbage yield in May was highest for the 400K-75P treatment and least for the 0K-0P treatment, differences that were associated with variation in mass shoot −1 and not shoots m −2 .”
t0“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
May yield differences were associated with mass per shoot rather than shoot density.
- Taxon
- alfalfa ( Medicago sativa L.)Medicago sativat0
- Organ / stage
- shoote0
- Outcome
- differencese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“differences that were associated with variation in mass shoot −1 and not shoots m −2”
t0“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
High May yield with 400K-75P was associated with greater taproot amino-N, soluble protein and RNA accumulation and use.
- Taxon
- alfalfa ( Medicago sativa L.)Medicago sativat0
- Material
- 400K-75P plantse0
- Outcome
- High yielde0
- Qualifier
- greater concentrations and use of amino-N, soluble protein, and RNA poolse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“High yield of the 400K-75P plants in May was consistently associated with greater concentrations and use of amino-N, soluble protein, and RNA pools in taproots, and not with accumulation and use of starch and sugar pools.”
t0“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
High May yield with 400K-75P was not associated with taproot starch and sugar accumulation and use.
- Taxon
- alfalfa ( Medicago sativa L.)Medicago sativat0
- Material
- 400K-75P plantse0
- Outcome
- High yielde0
- Qualifier
- not with accumulation and use of starch and sugar poolse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“High yield of the 400K-75P plants in May was consistently associated with greater concentrations and use of amino-N, soluble protein, and RNA pools in taproots, and not with accumulation and use of starch and sugar pools.”
t0“alfalfa ( Medicago sativa L.)”
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See all 59 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.