Abstract
We used a video digitizer system to (a) measure changes in the pattern of longitudinal surface extension in primary roots of maize (Zea mays L.) upon application and withdrawal of auxin and (b) compare these patterns during gravitropism in control roots and roots pretreated with auxin. Special attention was paid to the distal elongation zone (DEZ), arbitrarily defined as the region between the meristem and the point within the elongation zone at which the rate of elongation reaches 0.3 of the peak rate. For roots in aqueous solution, the basal limit of the DEZ is about 2.5 mm behind the tip of the root cap. Auxin suppressed elongation throughout the elongation zone, but, after 1 to 3 h, elongation resumed, primarily as a result of induction of rapid elongation in the DEZ. Withdrawal of auxin during the period of strong inhibition resulted in exceptionally rapid elongation attributable to the initiation of rapid elongation in the DEZ plus recovery in the main elongation zone. Gravistimulation of auxin-inhibited roots induced rapid elongation in the DEZ along the top of the root. This resulted in rapid gravitropism even though the elongation rate of the root was zero before gravistimulation. The results indicate that cells of the DEZ differ from cells in the bulk of the elongation zone with respect to auxin sensitivity and that DEZ cells play an important role in gravitropism.
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Claims 8
Claim · model-written summary
The distal elongation zone ended about 2.5 mm behind the root cap tip in aqueous solution.
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For roots in aqueous solution, the basal limit of the DEZ is about 2.5 mm behind the tip of the root cap”
t0“Maize”
Claim · model-written summary
Auxin suppressed root elongation throughout the elongation zone.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Auxin suppressed elongation throughout the elongation zone”
t0“Maize”
Claim · model-written summary
After 1 to 3 h of auxin treatment, elongation resumed mainly through rapid distal elongation zone elongation.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“after 1 to 3 h, elongation resumed, primarily as a result of induction of rapid elongation in the DEZ”
t0“Maize”
Claim · model-written summary
Auxin withdrawal during strong inhibition caused exceptionally rapid elongation in both distal and main elongation zones.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Withdrawal of auxin during the period of strong inhibition resulted in exceptionally rapid elongation attributable to the initiation of rapid elongation in the DEZ plus recovery in the main elongation zone”
t0“Maize”
Claim · model-written summary
Gravistimulation of auxin-inhibited roots induced rapid elongation on the top of the distal elongation zone.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Gravistimulation of auxin-inhibited roots induced rapid elongation in the DEZ along the top of the root”
t0“Maize”
Claim · model-written summary
Gravistimulation produced rapid gravitropism despite a zero prior root elongation rate.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This resulted in rapid gravitropism even though the elongation rate of the root was zero before gravistimulation”
t0“Maize”
Claim · model-written summary
Distal elongation zone cells differed from other elongation zone cells in auxin sensitivity.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cells of the DEZ differ from cells in the bulk of the elongation zone with respect to auxin sensitivity”
t0“Maize”
Claim · model-written summary
Distal elongation zone cells were implicated in gravitropism.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“DEZ cells play an important role in gravitropism”
t0“Maize”
The same questions in other papers
class · growth · Zea mays (maize)Positive and negative results
52 papers in the same direction as this paper · 15 in the opposite direction
- negative
- negative
- no effect
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See all 68 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.