Abstract
Abstract In a companion paper (10), varieties of four plant species [two monocotyledons (oats and corn) and two dicotyledons (soybeans and tomato)] were shown to differ widely in their ability to respond to Fe‐stress. The ability of the more Fe‐efficient varieties was manifested by a lowering of the pH of the ambient medium of the root and/or by loss of reductants from the root. Both effects can enhance uptake of Fe by the roots, since Fe is taken up primarily, if not entirely, as Fe2+ ions. Thus, a given stressed plant has a means, under some degree of metabolic control, for modifying the root environment and, thereby, alleviating its chlorotic condition. The present investigation deals with environmental factors, particularly chemical inhibitors, modifying the effectiveness of the stress response. Without inhibitors, excised root samples of the four species exhibited a wide range of abilities to reduce Fe3+ to Fe2+. Roots of the dicotyledonous species reduced about twice as much Fe3+ as did equal weights of the monocotyledonous species. Iron‐efficient tomato, soybean, and oat roots reduced more Fe3+ than did roots of the Fe‐inefficient varieties. The two corn varieties were about equal in their effectiveness. Comparable samples of roots were also exposed to chemicals that induce or aggravate Fe chlorosis. Those found to be very effective inhibitors of Fe3+ reduction by the roots included: hydroxide, orthophosphate, pyrophosphate, Cu2+ and Ni2+. Other ions (includ ing Mn2+, Zn2+ and molybdate) and ethyl ammonium phosphate also inhibited Fe3+ reduction but to a lesser degree. Citrate, however, enhanced Fe3+ reduction. The degree of inhibition or enhancement differed for each of the varieties. In general, the Fe‐efficient plants were best able to reduce Fe3+ in spite of the inhibitory influence of the imposed treatments. Thus, our findings indicated that inhibition of the Fe3+ ‐reduction process at, or near, the periphery of the root is an apparent cause of Fe chlorosis.
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Claims 13
Claim · model-written summary
Excised roots of four species varied widely in Fe3+ reduction.
Verbatim
e0“excised root samples of the four species exhibited a wide range of abilities to reduce Fe3+ to Fe2+”
t0“oats and corn) and two dicotyledons (soybeans and tomato)”
Claim · model-written summary
Dicotyledon roots reduced about twice as much Fe3+ as monocotyledon roots.
Verbatim
e0“Roots of the dicotyledonous species reduced about twice as much Fe3+ as did equal weights of the monocotyledonous species.”
Claim · model-written summary
Iron-efficient tomato, soybean and oat roots reduced more Fe3+ than inefficient varieties.
- Taxon
- tomato, soybean, and oat
Glycine max
Solanum lycopersicum
Avena sativae0 - Material
- Iron‐efficiente0
- Outcome
- Fe3+e0
- Direction
- moree0
- Comparator
- Fe‐inefficient varietiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Iron‐efficient tomato, soybean, and oat roots reduced more Fe3+ than did roots of the Fe‐inefficient varieties.”
Claim · model-written summary
The two corn varieties reduced Fe3+ equally.
- Taxon
- corn
Zea mays subsp. mayse0 - Outcome
- effectivenesse0
- Direction
- about equale0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The two corn varieties were about equal in their effectiveness.”
Claim · model-written summary
Hydroxide, orthophosphate and pyrophosphate strongly inhibited root Fe3+ reduction.
- Taxon
- plantsViridiplantaet0
- Treatment
- hydroxide, orthophosphate, pyrophosphatee0
- Outcome
- Fe3+ reduction by the rootse0
- Direction
- inhibitorse0
Not reportedComparator
Verbatim
e0“Those found to be very effective inhibitors of Fe3+ reduction by the roots included: hydroxide, orthophosphate, pyrophosphate, Cu2+ and Ni2+.”
t0“plants”
Claim · model-written summary
Cu2+ strongly inhibited root Fe3+ reduction.
- Taxon
- plantsViridiplantaet0
- Treatment
- Cu2+e0
- Outcome
- Fe3+ reduction by the rootse0
- Direction
- inhibitorse0
Not reportedComparator
Verbatim
e0“Those found to be very effective inhibitors of Fe3+ reduction by the roots included: hydroxide, orthophosphate, pyrophosphate, Cu2+ and Ni2+.”
t0“plants”
Claim · model-written summary
Ni2+ strongly inhibited root Fe3+ reduction.
- Taxon
- plantsViridiplantaet0
- Treatment
- Ni2+e0
- Outcome
- Fe3+ reduction by the rootse0
- Direction
- inhibitorse0
Not reportedComparator
Verbatim
e0“Those found to be very effective inhibitors of Fe3+ reduction by the roots included: hydroxide, orthophosphate, pyrophosphate, Cu2+ and Ni2+.”
t0“plants”
Claim · model-written summary
Mn2+, Zn2+ and molybdate inhibited Fe3+ reduction less strongly.
- Taxon
- plantsViridiplantaet0
- Treatment
- Mn2+, Zn2+ and molybdatee0
- Outcome
- Fe3+ reductione0
- Direction
- inhibitede0
- Qualifier
- to a lesser degreee0
Not reportedComparator
Verbatim
e0“Other ions (includ ing Mn2+, Zn2+ and molybdate) and ethyl ammonium phosphate also inhibited Fe3+ reduction but to a lesser degree.”
t0“plants”
Claim · model-written summary
Ethyl ammonium phosphate inhibited Fe3+ reduction less strongly.
- Taxon
- plantsViridiplantaet0
- Treatment
- ethyl ammonium phosphatee0
- Outcome
- Fe3+ reductione0
- Direction
- inhibitede0
- Qualifier
- to a lesser degreee0
Not reportedComparator
Verbatim
e0“Other ions (includ ing Mn2+, Zn2+ and molybdate) and ethyl ammonium phosphate also inhibited Fe3+ reduction but to a lesser degree.”
t0“plants”
Claim · model-written summary
Citrate enhanced Fe3+ reduction.
- Taxon
- plantsViridiplantaet0
- Treatment
- Citratee0
- Outcome
- Fe3+ reductione0
- Direction
- enhancede0
Not reportedComparator
Verbatim
e0“Citrate, however, enhanced Fe3+ reduction.”
t0“plants”
Claim · model-written summary
Chemical inhibition or enhancement differed among varieties.
- Taxon
- plantsViridiplantaet0
- Outcome
- degree of inhibition or enhancemente0
Verbatim
e0“The degree of inhibition or enhancement differed for each of the varieties.”
t0“plants”
Claim · model-written summary
Fe-efficient plants retained more Fe3+ reducing ability under inhibitory treatments.
Verbatim
e0“the Fe‐efficient plants were best able to reduce Fe3+ in spite of the inhibitory influence of the imposed treatments.”
Claim · model-written summary
Inhibition of root Fe3+ reduction apparently causes Fe chlorosis.
- Taxon
- plantsViridiplantaet0
- Outcome
- Fe chlorosise0
- Qualifier
- inhibition of the Fe3+ ‐reduction process at, or near, the periphery of the roote0
Verbatim
e0“inhibition of the Fe3+ ‐reduction process at, or near, the periphery of the root is an apparent cause of Fe chlorosis.”
t0“plants”
The same questions in other papers
phosphorus · nutrient: content · Viridiplantae (plants)Positive and negative results
5 papers in the same direction as this paper · 12 in the opposite direction
- positive
- positive
- positive
14 papers more in this group
See all 18 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.