Abstract
1. Investigations of physiological and chemical aspects of heat injury have been continued. Isolated dry embryonic axes (hereafter termed "embryos") of Red Kidney bean seeds (Phaseolus vulgaris) were untreated or treated by exposure to 100⚬ or 103⚬ C. for periods up to 45 minutes; they were then cultured in Petri dishes in tap or distilled water. Growth data and comparisons between growth and metabolic features of embryos are based primarily on their elongation rate. Physiological studies were conducted to determine the relation to heat injury of light, reducing agents and oxygen, and indole-3-acetic acid. Respiratory activity, amyloclastic, catalase, and peroxidase activities, and changes in chemical composition of heat-injured and control embryos were measured. Comparisons between growth and metabolic activity were carried out using embryos incubated for 50 hours after heat treatments which reduced elongation rate to 15% of the control value. 2. Embryos incubated in light ("day-light" fluorescent, 200 foot-candles) grew more than those in darkness. Photostimulation was evident in untreated embryos, but the relative effect of light was greater after exposure of embryos to 100⚬ C. 3. Injury was markedly limited when embryos were heated under conditions of reduced oxygen tension; application of cysteine to heat-injured embryos was also compensatory to a limited extent. 4. Application of indole-3-acetic acid inhibited the elongation of control (untreated) embryos but stimulated heatinjured plants. 5. Respiratory activity of heat-injured embryos exhibited "recovery," increasing from about 16% of the control after 1 hour of incubation to 80% of the control after 50 hours of incubation. Respiratory quotients of entire embryos were found to be approximately one, but no consistent differences between control and treated groups were noted. 6. One-third of the heat-treated embryos exhibited a malformation consisting of segmentation in the basal region of the hypocotyl. Microscopic examination of freehand sections showed that malformed embryos possessed only a remnant of pith, whereas the pith formed a solid cylinder of tissue in controls. Development of root hairs was retarded in heat-injured embryos. 7. Neither amyloclastic nor catalase activity was materially affected by the temperature treatment employed, but total peroxidase activity was 21% less in heat-injured incubated embryos than in controls. The distribution of peroxidase activity in incubated embryos was studied comparing root, hypocotyl, and plumule-plus-bud on a fresh-weight basis. The peroxidase gradient in controls paralleled that of embryonic activity, being higher in apical regions than in the hypocotyl. Peroxidase activities of treated plumule-plus-bud and hypocotyl were similar to those found for control organs, but treated incubated roots possessed only one-fifth as much activity as control incubated roots. 8. Analyses revealed that some of the soluble carbohydrate fraction had leached into the growing medium. Five times as much carbohydrate was lost from heat-injured tissues as from controls. Neither a starch nor a nitrogen loss from embryos was detected in leachates. 9. The data are discussed with regard to (a) protein denaturation as a process in heat injury; (b) the role of oxidation in heat injury; (c) reactivation of heatinjured embryos by light; (d) respiratory activity of embryos; (e) relationship of metabolic activity to viability; (f) permeability; and (g) possible relationships between heat injury and aging. 10. The following suggestions and conclusions are presented: (a) oxidation is an important factor in heat injury, and in Red Kidney bean embryos its effects are largely irreversible; (b) parallels may be drawn between the reactivation by light of heat-injured embryos and the photoreactivation of ultraviolet-inactivated microorganisms; (c) of the metabolic features studied, only the localized reduction in root peroxidase can be correlated with loss of viability; (d) gross color tests for viability were entirely unsuitable for distinguishing nonviable from viable individuals in this experiment; and (e) in many respects heat injury may operate as an accelerated aging process.
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Claims 20
Claim · model-written summary
Isolated Red Kidney bean embryos incubated in light grew more than those in darkness.
Verbatim
e0“Embryos incubated in light”
e1“grew more than those in darkness”
t0“Red Kidney Bean”
Claim · model-written summary
The relative effect of light was greater after exposure of embryos to 100⚬ C.
Verbatim
e0“the relative effect of light was greater after exposure of embryos to 100⚬ C”
t0“Red Kidney Bean”
Claim · model-written summary
Heat injury to embryos was markedly limited when they were heated under reduced oxygen tension.
Not reportedComparator
Verbatim
e0“Injury was markedly limited when embryos were heated under conditions of reduced oxygen tension”
t0“Red Kidney Bean”
Claim · model-written summary
Application of cysteine to heat-injured embryos was compensatory to a limited extent.
- Taxon
- Red Kidney Beant0
- Treatment
- application of cysteinee0
- Outcome
- compensatorye0
- Direction
- compensatory to a limited extente0
Not reportedComparator
Verbatim
e0“application of cysteine to heat-injured embryos was also compensatory to a limited extent”
t0“Red Kidney Bean”
Claim · model-written summary
Indole-3-acetic acid inhibited elongation of control untreated embryos.
Verbatim
e0“Application of indole-3-acetic acid inhibited the elongation of control (untreated) embryos but stimulated heatinjured plants”
t0“Red Kidney Bean”
Claim · model-written summary
Indole-3-acetic acid stimulated elongation of heat-injured plants.
- Taxon
- Red Kidney Beant0
- Treatment
- indole-3-acetic acide0
- Outcome
- elongatione0
- Direction
- stimulatede0
- Qualifier
- heatinjured plantse0
Not reportedComparator
Verbatim
e0“Application of indole-3-acetic acid inhibited the elongation of control (untreated) embryos but stimulated heatinjured plants”
t0“Red Kidney Bean”
Claim · model-written summary
Respiratory activity of heat-injured embryos recovered from about 16% of the control after 1 hour to 80% of the control after 50 hours of incubation.
Verbatim
e0“Respiratory activity of heat-injured embryos”
e1“increasing from about 16% of the control after 1 hour of incubation to 80% of the control after 50 hours of incubation”
t0“Red Kidney Bean”
Claim · model-written summary
Respiratory quotients of entire embryos were approximately one, with no consistent differences between control and treated groups.
Verbatim
e0“Respiratory quotients of entire embryos were found to be approximately one, but no consistent differences between control and treated groups were noted”
t0“Red Kidney Bean”
Claim · model-written summary
One-third of heat-treated embryos showed a malformation with segmentation of the basal hypocotyl; malformed embryos had only a remnant of pith whereas controls had a solid pith cylinder.
Verbatim
e0“One-third of the heat-treated embryos exhibited a malformation consisting of segmentation in the basal region of the hypocotyl”
e1“malformed embryos possessed only a remnant of pith, whereas the pith formed a solid cylinder of tissue in controls”
t0“Red Kidney Bean”
Claim · model-written summary
Development of root hairs was retarded in heat-injured embryos.
Verbatim
e0“Development of root hairs was retarded in heat-injured embryos”
t0“Red Kidney Bean”
Claim · model-written summary
Neither amyloclastic nor catalase activity was materially affected by the temperature treatment.
- Taxon
- Red Kidney Beant0
- Treatment
- temperature treatmente0
- Outcome
- amyloclastic nor catalase activitye0
- Direction
- Neithere0
Not reportedComparator
Verbatim
e0“Neither amyloclastic nor catalase activity was materially affected by the temperature treatment employed”
t0“Red Kidney Bean”
Claim · model-written summary
Total peroxidase activity was 21% less in heat-injured incubated embryos than in controls.
Verbatim
e0“total peroxidase activity was 21% less in heat-injured incubated embryos than in controls”
t0“Red Kidney Bean”
Claim · model-written summary
Peroxidase activities of treated plumule-plus-bud and hypocotyl were similar to those of control organs.
Verbatim
e0“Peroxidase activities of treated plumule-plus-bud and hypocotyl were similar to those found for control organs”
t0“Red Kidney Bean”
Claim · model-written summary
Treated incubated roots had only one-fifth as much peroxidase activity as control incubated roots.
Verbatim
e0“treated incubated roots possessed only one-fifth as much activity as control incubated roots”
t0“Red Kidney Bean”
Claim · model-written summary
Five times as much soluble carbohydrate was lost from heat-injured tissues as from controls.
Verbatim
e0“Five times as much carbohydrate was lost from heat-injured tissues as from controls”
t0“Red Kidney Bean”
Claim · model-written summary
Neither starch nor nitrogen loss from embryos was detected in leachates.
Verbatim
e0“Neither a starch nor a nitrogen loss from embryos was detected in leachates”
t0“Red Kidney Bean”
Claim · model-written summary
The authors conclude that oxidation is an important factor in heat injury in Red Kidney bean embryos and its effects are largely irreversible.
Verbatim
e0“oxidation is an important factor in heat injury, and in Red Kidney bean embryos its effects are largely irreversible”
t0“Red Kidney Bean”
Claim · model-written summary
Of the metabolic features studied, only the localized reduction in root peroxidase can be correlated with loss of viability.
- Taxon
- Red Kidney Beant0
- Organ / stage
- roote0
- Outcome
- loss of viabilitye0
- Qualifier
- localized reduction in root peroxidasee0
Not reportedDirection
Verbatim
e0“only the localized reduction in root peroxidase can be correlated with loss of viability”
t0“Red Kidney Bean”
Claim · model-written summary
Gross color tests for viability were entirely unsuitable for distinguishing nonviable from viable individuals.
Verbatim
e0“gross color tests for viability were entirely unsuitable for distinguishing nonviable from viable individuals in this experiment”
t0“Red Kidney Bean”
Claim · model-written summary
The authors suggest that in many respects heat injury may operate as an accelerated aging process.
Verbatim
e0“in many respects heat injury may operate as an accelerated aging process”
t0“Red Kidney Bean”
The same questions in other papers
indole-3-acetic acid · growth · Phaseolus vulgaris (common bean)Results differ
17 papers in the same direction as this paper · 13 in the opposite direction · 1 reporting no difference from an alternative
- negative
- negative
- negative
28 papers more in this group
See all 32 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.