Abstract
The physiological characteristics of the response of excised cowpea (Vigna sinensis cv Blackeye pea No. 5) epicotyls to gibberellins (GAs) were studied. Epicotyl explants, retaining the petioles and a 2-cm portion of hypocotyl, were placed upright in small vials containing water. Plant growth substances were injected into the subapical tissues as ethanol solutions.
Epicotyl elongation resulting from treatment with 0.5 μg of GA ranged between 5 and 13 times that of the control, depending on the GA applied. With GA1, no differences were obtained with explants prepared from 5 to 9-day-old seedlings. The increase in elongation could be detected within 6 h of treatment, and the stimulus of a single application lasted at least 4 days. Final elongation was proportional to the logarithm of the amount of GA, applied, 0.01 to lug. The response to GA treatment was limited to the upper part, the most sensitive zone being located between 2 to 4 mm below the apex of the epicotyl; this effect was entirely due to cell elongation.
The induction of epicotyl elongation by GAs seems to be specific and independent of the effect of auxin. IAA had no effect on elongation and 4-chloro-phenoxyisobutyric acid (PCIB) did not affect the response to GA1
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Abbreviations
- ABA:
-
abscisic acid
- GA:
-
gibberellin
- IAA:
-
Indole-3-acetic acid
- TIBA:
-
2,3,5-triiodobenzoic acid
- PCIB:
-
4-chloro-phenoxyisobutyric acid
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Garcia-Martinez, J.L., Rappaport, L. Physiology of gibberellin-induced elongation of epicotyl explants from Vigna sinensis . Plant Growth Regul 2, 197–208 (1984). https://doi.org/10.1007/BF00124768
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DOI: https://doi.org/10.1007/BF00124768