Abstract
The purpose of this investigation is the study of the properties of the cell with regard to potassium absorption as the cell expands. Serial sections each 1·5 mm. in length have been cut along the course of maize roots over the first 9·0 mm. from the tip. The sections have been immersed in 0·01 N. solution of potassium chloride in water and in 2 per cent. fructose. Absorption from these solutions has been measured over a period of 48–72 hours. It is shown that absorption by the first section which consists almost entirely of meristematic cells is abnormally low, and this is attributed to the absence of a tonoplast surrounding a central vacuole in the cells of this section. The different initial rates with the different sections indicate that after vacuolation in the root has occurred the rate per unit area of surface decreases as the cell expands. When the data are reduced to a unit cell basis, however, they show that, per cell, absorption increases as expansion occurs in the root. This is attributed to an increasing protein content, and the decrease in rate per unit area to a corresponding decrease in protein per unit area. At the same time it is shown that during cell growth in the root the cytoplasm differentiates in such a way that absorption per unit protein increases. After excision, whether growth occurs or not, the protein content does not increase. The final internal concentrations in the different sections vary according to the growth that occurs. When vacuolation has occurred and growth is limited the final internal concentration is greater than it is at the beginning of the experiment. When growth occurs, on the other hand, the final internal concentration may be lower. This is taken to indicate that absorption depends on an inward secretion into the vacuole which is independent of surface area and an outward diffusion into the medium which increases with increase in surface area. It is suggested that the results obtained with sugar support this interpretation. When sugar is provided the rate of absorption is always stimulated and when growth does not occur the final internal concentration is enhanced. When growth occurs, however, sugar not only stimulates absorption but also the expansion of the cell, and the latter effect leads to a final concentration which may be lower than that given in the absence of sugar.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 18
Claim · model-written summary
Potassium absorption by the first, almost entirely meristematic root section is abnormally low.
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e1“absorption by the first section which consists almost entirely of meristematic cells is abnormally low, and this is attributed to the absence of a tonoplast surrounding a central vacuole in the cells of this section”
Claim · model-written summary
The low absorption of the first root section is attributed to the absence of a tonoplast around a central vacuole.
- Outcome
- absorption by the first sectione1
- Qualifier
- absence of a tonoplast surrounding a central vacuolee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e1“absorption by the first section which consists almost entirely of meristematic cells is abnormally low, and this is attributed to the absence of a tonoplast surrounding a central vacuole in the cells of this section”
Claim · model-written summary
The rate per unit area of surface decreases as cells expand after vacuolation in the root.
- Organ / stage
- after vacuolatione3
- Outcome
- rate per unit area of surfacee3
- Direction
- decreasese3
- Qualifier
- as the cell expandse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e3“after vacuolation in the root has occurred the rate per unit area of surface decreases as the cell expands”
Claim · model-written summary
Per cell, potassium absorption increases as expansion occurs in the root.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e4“When the data are reduced to a unit cell basis, however, they show that, per cell, absorption increases as expansion occurs in the root”
Claim · model-written summary
Per-cell absorption increase is attributed to increasing protein content.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e4“When the data are reduced to a unit cell basis, however, they show that, per cell, absorption increases as expansion occurs in the root”
e5“This is attributed to an increasing protein content, and the decrease in rate per unit area to a corresponding decrease in protein per unit area”
Claim · model-written summary
The decrease in rate per unit area is attributed to a decrease in protein per unit area.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e5“This is attributed to an increasing protein content, and the decrease in rate per unit area to a corresponding decrease in protein per unit area”
Claim · model-written summary
Absorption per unit protein increases during cell growth in the root as cytoplasm differentiates.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e6“At the same time it is shown that during cell growth in the root the cytoplasm differentiates in such a way that absorption per unit protein increases”
Claim · model-written summary
After excision, protein content does not increase whether or not growth occurs.
- Outcome
- protein contente7
- Direction
- does not increasee7
- Qualifier
- After excision, whether growth occurs or note7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e7“After excision, whether growth occurs or not, the protein content does not increase”
Claim · model-written summary
Final internal potassium concentrations in the sections vary according to the growth that occurs.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e2“The final internal concentrations in the different sections vary according to the growth that occurs”
Claim · model-written summary
After vacuolation with limited growth, the final internal concentration is greater than at the beginning of the experiment.
- Outcome
- final internal concentratione3
- Direction
- greatere3
- Qualifier
- When vacuolation has occurred and growth is limitede3
- Comparator
- at the beginning of the experimente3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e3“When vacuolation has occurred and growth is limited the final internal concentration is greater than it is at the beginning of the experiment”
Claim · model-written summary
When growth occurs, the final internal concentration may be lower.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e4“When growth occurs, on the other hand, the final internal concentration may be lower”
Claim · model-written summary
Absorption depends on an inward secretion into the vacuole that is independent of surface area.
- Outcome
- absorptione5
- Qualifier
- an inward secretion into the vacuole which is independent of surface areae5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e5“absorption depends on an inward secretion into the vacuole which is independent of surface area and an outward diffusion into the medium which increases with increase in surface area”
Claim · model-written summary
Absorption includes an outward diffusion into the medium that increases with surface area.
- Outcome
- absorptione5
- Qualifier
- an outward diffusion into the medium which increases with increase in surface areae5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e5“absorption depends on an inward secretion into the vacuole which is independent of surface area and an outward diffusion into the medium which increases with increase in surface area”
Claim · model-written summary
Sugar stimulates the rate of potassium absorption.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e6“When sugar is provided the rate of absorption is always stimulated and when growth does not occur the final internal concentration is enhanced”
Claim · model-written summary
When growth does not occur, sugar enhances the final internal concentration.
- Treatment
- sugare6
- Outcome
- final internal concentratione6
- Direction
- enhancede6
- Qualifier
- when growth does not occure6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e6“When sugar is provided the rate of absorption is always stimulated and when growth does not occur the final internal concentration is enhanced”
Claim · model-written summary
When growth occurs, sugar stimulates potassium absorption.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e7“When growth occurs, however, sugar not only stimulates absorption but also the expansion of the cell, and the latter effect leads to a final concentration which may be lower than that given in the absence of sugar”
Claim · model-written summary
When growth occurs, sugar stimulates expansion of the cell.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e7“When growth occurs, however, sugar not only stimulates absorption but also the expansion of the cell, and the latter effect leads to a final concentration which may be lower than that given in the absence of sugar”
Claim · model-written summary
The expansion effect of sugar may lead to a final concentration lower than without sugar.
- Treatment
- sugare7
- Outcome
- final concentratione7
- Direction
- lowere7
- Qualifier
- may bee7
- Comparator
- in the absence of sugare7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“along the course of maize roots”
e7“When growth occurs, however, sugar not only stimulates absorption but also the expansion of the cell, and the latter effect leads to a final concentration which may be lower than that given in the absence of sugar”