Abstract
Ricinus communis L. (castor bean) plants were grown in the absence (control) and in the presence of 100molm−3NaCl with a reciprocal split-root system, in which K+ was supplied to one and NO3− to the other part of the root system. In these plants shoot and, to a lesser extent, total root growth were inhibited compared to plants with non-split roots. Without and with NaCl, growth of roots receiving NO3− but noK+ (‘minus K/plus N-roots’) was substantially more vigorous than under the reverse conditions (‘plus K/minus N-roots1).100 mol m−3 NaCl inhibited growth of minus K/plus N-roots1 to the same extent as that of non-split roots, indicating that externally supplied K+ was not required for root growth under saline conditions. In growth media without added K+ the root depleted the external low K + levels resulting from chemicals down to a minimum value Cmln (1.0 to 1.4 mmol m−3); in the presence of 100 mol m−3 NaCl, Cmin, was higher (10–18 mmol m−3) and resulted from an initial net loss of K +. Cmin, was pH-dependent The distribution of K+, Na+ and Mg2+ along the root was measured. In meristematic root tissues, K + concentrations were scarcely affected by external K+ or by NaCl, where Na + concentrations were low, but somewhat elevated at low external K+ and/or high NaCl. In differentiated, vacuolated tissues K + concentrations were low and Na+ concentrations high, if K + was not supplied externally and/or NaCl was present. The longitudinal distribution of ions within the root was used to estimate cytoplasmic and vacuolar ion concentrations. These data showed a narrow homoeostasis of cytoplasmic K+ concentrations (100–140 mol m−3) independent of external K + supply even in the presence of 100 mol m −3 NaCl. Cytoplasmic Na + concentrations were maintained at remarkably low levels. Hence, external K+ concentrations above Cmin, were not required for maintaining K/Na selectivity, i.e. for controlling Na+ entry. The results are discussed with regard to mechanisms of K/Na selectivity and to the importance of phloem import of K+ for salt tolerance of roots and for cytoplasmic K+ homoeostasis.
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Claims 11
Claim · model-written summary
Split-root treatment inhibited shoot and total root growth relative to nonsplit roots.
- Taxon
- Ricinus communis L.
Ricinus communise1 - Treatment
- reciprocal split-root systeme1
- Outcome
- shoot and, to a lesser extent, total root growthe0
- Direction
- inhibitede0
- Comparator
- plants with non-split rootse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In these plants shoot and, to a lesser extent, total root growth were inhibited compared to plants with non-split roots.”
e1“Ricinus communis L. (castor bean) plants were grown in the absence (control) and in the presence of 100molm−3NaCl with a reciprocal split-root system”
Claim · model-written summary
Roots receiving nitrate without potassium grew more vigorously than roots receiving potassium without nitrate.
- Taxon
- Ricinus communisRicinus communist0
- Treatment
- NO3− but noK+e0
- Outcome
- growth of rootse0
- Direction
- more vigorouse0
- Comparator
- plus K/minus N-roots1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Without and with NaCl, growth of roots receiving NO3− but noK+ (‘minus K/plus N-roots’) was substantially more vigorous than under the reverse conditions (‘plus K/minus N-roots1).”
t0“Ricinus communis”
Claim · model-written summary
NaCl inhibited nitrate supplied roots without potassium to the same extent as nonsplit roots.
- Taxon
- Ricinus communisRicinus communist0
- Treatment
- 100 mol m−3 NaCle0
- Outcome
- growth of minus K/plus N-roots1e0
- Direction
- inhibitede0
- Comparator
- non-split rootse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“100 mol m−3 NaCl inhibited growth of minus K/plus N-roots1 to the same extent as that of non-split roots”
t0“Ricinus communis”
Claim · model-written summary
Minimum external potassium was higher under NaCl, after initial net potassium loss.
- Taxon
- Ricinus communisRicinus communist0
- Outcome
- Cmin,e0
- Direction
- highere0
- Value
- 10–18 mmol m−3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in the presence of 100 mol m−3 NaCl, Cmin, was higher (10–18 mmol m−3) and resulted from an initial net loss of K +”
t0“Ricinus communis”
Claim · model-written summary
Without added potassium, roots depleted external potassium to a minimum of 1.0 to 1.4 mmol m−3.
- Taxon
- Ricinus communisRicinus communist0
- Outcome
- external low K + levelse0
- Direction
- depletede0
- Value
- 1.0 to 1.4 mmol m−3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In growth media without added K+ the root depleted the external low K + levels resulting from chemicals down to a minimum value Cmln (1.0 to 1.4 mmol m−3)”
t0“Ricinus communis”
Claim · model-written summary
Minimum external potassium depended on pH.
- Taxon
- Ricinus communisRicinus communist0
- Outcome
- Cmin,e0
- Qualifier
- pH-dependente0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cmin, was pH-dependent”
t0“Ricinus communis”
Claim · model-written summary
Meristematic root potassium concentrations were scarcely affected by external potassium or NaCl.
- Taxon
- Ricinus communisRicinus communist0
- Organ / stage
- meristematic root tissuese0
- Treatment
- external K+ or by NaCle0
- Outcome
- K + concentrationse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In meristematic root tissues, K + concentrations were scarcely affected by external K+ or by NaCl”
t0“Ricinus communis”
Claim · model-written summary
Under low external potassium or NaCl, differentiated root tissues had low potassium and high sodium.
- Taxon
- Ricinus communisRicinus communist0
- Organ / stage
- differentiated, vacuolated tissuese0
- Outcome
- K + concentrations were low and Na+ concentrations highe0
- Qualifier
- K + was not supplied externally and/or NaCl was presente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In differentiated, vacuolated tissues K + concentrations were low and Na+ concentrations high, if K + was not supplied externally and/or NaCl was present”
t0“Ricinus communis”
Claim · model-written summary
Cytoplasmic potassium stayed at 100–140 mol m−3 independently of external potassium under salinity.
- Taxon
- Ricinus communisRicinus communist0
- Outcome
- cytoplasmic K+ concentrationse0
- Value
- 100–140 mol m−3e0
- Qualifier
- independent of external K + supply even in the presence of 100 mol m −3 NaCle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“narrow homoeostasis of cytoplasmic K+ concentrations (100–140 mol m−3) independent of external K + supply even in the presence of 100 mol m −3 NaCl”
t0“Ricinus communis”
Claim · model-written summary
Cytoplasmic sodium concentrations remained low.
- Taxon
- Ricinus communisRicinus communist0
- Outcome
- Cytoplasmic Na + concentrationse0
- Direction
- lowe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cytoplasmic Na + concentrations were maintained at remarkably low levels.”
t0“Ricinus communis”
Claim · model-written summary
External potassium above the minimum was unnecessary to maintain K/Na selectivity.
- Taxon
- Ricinus communisRicinus communist0
- Treatment
- external K+ concentrations above Cmin,e0
- Outcome
- K/Na selectivitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“external K+ concentrations above Cmin, were not required for maintaining K/Na selectivity, i.e. for controlling Na+ entry”
t0“Ricinus communis”
The same questions in other papers
sodium chloride · growth · Ricinus communis (castor bean)Positive and negative results
4 papers in the same direction as this paper · 1 in the opposite direction
- positive
- negative
- negative
2 papers more in this group
See all 6 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.