Abstract
Abstract Ferrous iron (Iron2+ and Fe2+) has been considered by many investigators to be the active form of iron (Fe) in plants. Experiments were conducted to determine differences in Fe2+ and total Fe in newly emerging leaves of sorghum [Sorghum bicolor (L.) Moench] and maize (Zea mays L.) genotypes considered to be “Fe‐susceptible”; and “Fe‐tolerant”; to low levels of Fe. Treatments consisted of growing plants in nutrient solutions with Fe (+Fe) and without Fe (‐Fe) under growth chamber conditions. Once Fe deficiency chlorosis symptoms were visually observed in plants grown with ‐Fe, leaf samples were collected daily from plants grown in both ‐Fe and +Fe solutions for Fe2+ and total Fe determinations. Iron2+ in the newly emerging leaves of plants grown in ‐Fe or +Fe solutions remained fairly constant. Total Fe changed daily and was dependent on the amount of Fe deficiency stress in sorghum, but not necessarily in maize. Total Fe and Fe2+ values were fairly similar in plants with severe Fe deficiency chlorosis symptoms. Sorghum and maize plants regreened after Fe had been added to the growth solutions and total Fe increased within the developing leaves of these plants within two to three days. Total Fe increases appeared to be rhythmic in sorghum. Total Fe changes were related to the degree of Fe deficiency stress, but Fe2+ was not2+. The active Fe in the leaves of these plants was not related to Fe2+ , but to total Fe (or Fe3+ if total Fe minus Fe2+ is equivalent to Fe3+ ). The daily fluctuations of total Fe may help explain why Fe deficient leaves often contain more Fe than green leaves.
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Claims 10
Claim · model-written summary
Leaf Iron2+ remained fairly constant under both iron treatments.
Sorghum
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Iron2+ in the newly emerging leaves of plants grown in ‐Fe or +Fe solutions remained fairly constant.”
t0“Sorghum and maize”
Claim · model-written summary
Total Fe varied daily with deficiency stress in sorghum.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total Fe changed daily and was dependent on the amount of Fe deficiency stress in sorghum, but not necessarily in maize.”
Claim · model-written summary
The stress dependence of total Fe was uncertain for maize.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total Fe changed daily and was dependent on the amount of Fe deficiency stress in sorghum, but not necessarily in maize.”
Claim · model-written summary
Total Fe and Fe2+ values were similar in severely chlorotic plants.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total Fe and Fe2+ values were fairly similar in plants with severe Fe deficiency chlorosis symptoms.”
t0“Sorghum and maize”
Claim · model-written summary
Sorghum regreened after iron addition.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sorghum and maize plants regreened after Fe had been added to the growth solutions and total Fe increased within the developing leaves of these plants within two to three days.”
Claim · model-written summary
Sorghum leaf total Fe increased within two to three days of iron addition.
- Treatment
- Fe had been added to the growth solutionse0
- Outcome
- total Fee0
- Direction
- increasede0
- Qualifier
- within two to three dayse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sorghum and maize plants regreened after Fe had been added to the growth solutions and total Fe increased within the developing leaves of these plants within two to three days.”
Claim · model-written summary
maize regreened after iron addition.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sorghum and maize plants regreened after Fe had been added to the growth solutions and total Fe increased within the developing leaves of these plants within two to three days.”
Claim · model-written summary
maize leaf total Fe increased within two to three days of iron addition.
- Treatment
- Fe had been added to the growth solutionse0
- Outcome
- total Fee0
- Direction
- increasede0
- Qualifier
- within two to three dayse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sorghum and maize plants regreened after Fe had been added to the growth solutions and total Fe increased within the developing leaves of these plants within two to three days.”
Claim · model-written summary
Total Fe increases in sorghum appeared rhythmic.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total Fe increases appeared to be rhythmic in sorghum.”
Claim · model-written summary
The authors associated active leaf iron with total Fe or possibly Fe3+, rather than Fe2+.
- Compound
- total Fee0
- Outcome
- active Fe in the leavese0
- Qualifier
- or Fe3+ if total Fe minus Fe2+ is equivalent to Fe3+e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The active Fe in the leaves of these plants was not related to Fe2+ , but to total Fe (or Fe3+ if total Fe minus Fe2+ is equivalent to Fe3+ ).”
t0“Sorghum and maize”
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See all 54 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.