Abstract
In an effort to investigate possible involvement of abscisic acid (ABA) in foliar abscission processes, its movement and endogenous levels were examined in cotyledons taken from cotton seedlings (Gossypium hirsutum L.) subjected to varying degrees of water deficit, a condition which initiates leaf abscission. Using a pulse-labeling technique to avoid complications of uptake and exit from the tissue, ABA-1-14C movement was observed in both basipetal and acropetal directions in cotyledonary petioles taken from well watered, stressed, and rewatered plants. The label distribution patterns obtained after 1 and 3 hours of transport under all situations of water supply were diffusive in nature and did not change when tested under anaerobic conditions. The transport capacity of the petioles ranged from 3.6 to 14.4% ABA-1-14C transported per hour at estimated velocities of 0 to 2 millimeters per hour. Comparison of basipetal and acropetal movement indicated a lack of polarity under all conditions tested. These low transport capacities and slow velocities of movement, when compared to the active transport systems associated with auxin movement, as well as the lack of anaerobic effects and polarity, suggest that ABA movement in cotton cotyledonary petiole sections is facilitated by passive diffusion. Increases in free and bound ABA in the lamina with increased water stress did not correlate with patterns of cotyledonary abscission. Thus, no evidence was found to suggest that ABA is directly involved in stress-induced abscission processes.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Beyer E. M. Abscission: the initial effect of ethylene is in the leaf blade. Plant Physiol. 1975 Feb;55(2):322–327. doi: 10.1104/pp.55.2.322. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Davenport T. L., Morgan P. W., Jordan W. R. Auxin Transport as Related to Leaf Abscission during Water Stress in Cotton. Plant Physiol. 1977 Apr;59(4):554–557. doi: 10.1104/pp.59.4.554. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hocking T. J., Hillman J. R., Wilkins M. B. Movement of abscisic acid in Phaseolus vulgaris plants. Nat New Biol. 1972 Jan 26;235(56):124–125. doi: 10.1038/newbio235124a0. [DOI] [PubMed] [Google Scholar]
- Ingersoll R. B., Smith O. E. Movement of (RS)-Abscisic Acid in the Cotton Explant. Plant Physiol. 1970 May;45(5):576–578. doi: 10.1104/pp.45.5.576. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jordan W. R., Brown K. W., Thomas J. C. Leaf Age as a Determinant in Stomatal Control of Water Loss from Cotton during Water Stress. Plant Physiol. 1975 Nov;56(5):595–599. doi: 10.1104/pp.56.5.595. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Scholander P. F., Bradstreet E. D., Hemmingsen E. A., Hammel H. T. Sap Pressure in Vascular Plants: Negative hydrostatic pressure can be measured in plants. Science. 1965 Apr 16;148(3668):339–346. doi: 10.1126/science.148.3668.339. [DOI] [PubMed] [Google Scholar]
- Shindy W. W., Asmundson C. M., Smith O. E., Kumamoto J. Absorption and distribution of high specific radioactivity 2-C-abscisic Acid in cotton seedlings. Plant Physiol. 1973 Nov;52(5):443–447. doi: 10.1104/pp.52.5.443. [DOI] [PMC free article] [PubMed] [Google Scholar]