Abstract
Intact or excised roots, immersed in anaerobic aqueous agar media with or without additions of sugar, were made anoxic by exposing the shoots (or cut-ends) to oxygen-free nitrogen. Polarographic monitoring of the internal oxygen status showed that roots rapidly became anoxic; also extension growth immediately declined and was soon halted. Growth was re-started only by re-aeration and, in sugar deficient media, apices survived only if the period of anoxia had not exceeded 4 h (rice), 6 h (pea) and 12 h (pumpkin). Utilizable carbohydrate supplied exogenously could reduce the rate of decline in growth rate (rice and pumpkin) but could not of itself indefinitely sustain or induce growth; it enhanced viability, however, and rice became the most tolerant of anoxia (c. 44 h). Oxygen was essential both to sustain and initiate root extension but growth could cease and apical death ensue from an insufficiency of carbohydrate even in the presence of oxygen. It is concluded that the normal response of roots to anoxia is a hypersensitive one arising from sugar deficiency. The discussion relates the results to recent reports concerning carbohydrate and energy levels in anoxic and aerated roots, to work on ultrastructural change under anoxia, and to the subject of flood tolerance. The results are not thought to accord with a metabolic theory of flood-tolerance based upon differences in the accumulation and phytotoxicities of ethanol and other by-products of anaerobic respiration. They are considered to be more in keeping with the view that flood-tolerance in roots is chiefly a property of internal aeration and the potential for producing well-ventilated roots in response to soil wetness.
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Claims 11
Claim · model-written summary
Anoxia caused root extension growth to decline and halt.
Not reportedComparator
Verbatim
t0“The Effects of Anoxia and Carbohydrates on the Growth and Viability of Rice, Pea and Pumpkin Roots”
e1“Polarographic monitoring of the internal oxygen status showed that roots rapidly became anoxic; also extension growth immediately declined and was soon halted”
Claim · model-written summary
Rice apices survived anoxia only up to 4 h in sugar-deficient media.
- Taxon
- rice
Oryza sativae2 - Outcome
- apices survivede2
- Value
- 4 he2
- Qualifier
- in sugar deficient mediae2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“in sugar deficient media, apices survived only if the period of anoxia had not exceeded 4 h (rice), 6 h (pea) and 12 h (pumpkin)”
Claim · model-written summary
Pea apices survived anoxia only up to 6 h in sugar-deficient media.
- Taxon
- pea
Lathyrus oleraceuse2 - Outcome
- apices survivede2
- Value
- 6 he2
- Qualifier
- in sugar deficient mediae2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“in sugar deficient media, apices survived only if the period of anoxia had not exceeded 4 h (rice), 6 h (pea) and 12 h (pumpkin)”
Claim · model-written summary
Pumpkin apices survived anoxia only up to 12 h in sugar-deficient media.
Verbatim
e2“in sugar deficient media, apices survived only if the period of anoxia had not exceeded 4 h (rice), 6 h (pea) and 12 h (pumpkin)”
Claim · model-written summary
Exogenous utilizable carbohydrate reduced the rate of decline in growth rate under anoxia in rice and pumpkin.
- Taxon
- rice and pumpkine3
- Treatment
- Utilizable carbohydrate supplied exogenouslye3
- Outcome
- rate of decline in growth ratee3
- Direction
- reducee3
Not reportedComparator
Verbatim
e3“Utilizable carbohydrate supplied exogenously could reduce the rate of decline in growth rate (rice and pumpkin)”
Claim · model-written summary
Exogenous carbohydrate enhanced root viability under anoxia.
Not reportedComparator
Verbatim
t0“The Effects of Anoxia and Carbohydrates on the Growth and Viability of Rice, Pea and Pumpkin Roots”
e3“Utilizable carbohydrate supplied exogenously could reduce the rate of decline in growth rate (rice and pumpkin)”
e4“it enhanced viability, however, and rice became the most tolerant of anoxia (c. 44 h)”
Claim · model-written summary
Rice was the most tolerant of anoxia, about 44 h.
- Taxon
- riceOryza sativae4
- Outcome
- most tolerant of anoxiae4
- Value
- c. 44 he4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“it enhanced viability, however, and rice became the most tolerant of anoxia (c. 44 h)”
Claim · model-written summary
Oxygen was essential to sustain and initiate root extension.
Not reportedDirection
Verbatim
t0“The Effects of Anoxia and Carbohydrates on the Growth and Viability of Rice, Pea and Pumpkin Roots”
e5“Oxygen was essential both to sustain and initiate root extension”
Claim · model-written summary
Apical death of roots followed carbohydrate insufficiency even in the presence of oxygen.
- Taxon
- Rice, Pea and Pumpkint0
- Treatment
- insufficiency of carbohydratee6
- Outcome
- apical deathe6
- Qualifier
- even in the presence of oxygene6
Not reportedDirection
Verbatim
t0“The Effects of Anoxia and Carbohydrates on the Growth and Viability of Rice, Pea and Pumpkin Roots”
e6“growth could cease and apical death ensue from an insufficiency of carbohydrate even in the presence of oxygen”
Claim · model-written summary
The normal root response to anoxia is a hypersensitive response arising from sugar deficiency.
Verbatim
t0“The Effects of Anoxia and Carbohydrates on the Growth and Viability of Rice, Pea and Pumpkin Roots”
e7“It is concluded that the normal response of roots to anoxia is a hypersensitive one arising from sugar deficiency”
Claim · model-written summary
Flood tolerance in roots is chiefly a property of internal aeration.
Verbatim
t0“The Effects of Anoxia and Carbohydrates on the Growth and Viability of Rice, Pea and Pumpkin Roots”
e1“flood-tolerance in roots is chiefly a property of internal aeration”
The same questions in other papers
carbohydrate · growth · Oryza sativa (rice)Positive and negative results
1 in the opposite direction
- no effect
flooding · growth · Oryza sativa (rice)Positive and negative results
73 papers in the same direction as this paper · 64 in the opposite direction
- positive
- positive
- positive
134 papers more in this group
See all 138 papers →flooding · growth · Cucurbita (pumpkins)Results agree
1 paper in the same direction as this paper
- negative
flooding · growth · Lathyrus oleraceus (pea)Results agree
8 papers in the same direction as this paper
- negative
- negative
- negative
5 papers more in this group
See all 9 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.