ISSN:
1432-2048
Keywords:
Abscisic acid and stomata
;
Cytokinin and stomata
;
Gossypium (ABA, stomata)
;
Leaf aging
;
Nitrogen nutrition and stomata
;
Phaseic acid
;
Stoma (ABA and kinetin effects)
;
Water stress
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Suboptimal nitrogen nutrition, leaf aging, and prior exposure to water stress all increased stomatal closure in excised cotton (Gossypium hirsutum L.) leaves supplied abscisic acid (ABA) through the transpiration stream. The effects of water stress and N stress were partially reversed by simultaneous application of kinetin (N6-furfurylaminopurine) with the ABA, but the effect of leaf aging was not. These enhanced responses to ABA could have resulted either from altered rates of ABA release from symplast to apoplast, or from some “post-release” effect involving ABA transport to, or detection by, the guard cells. Excised leaves were preloaded with [14C]ABA and subjected to overpressures in a pressure chamber to isolate apoplastic solutes in the exudate. Small quantities of 14C were released into the exudate, with the amount increasing greatly with increasing pressure. Over the range of pressures from 1 to 2.5 MPa, ABA in the exudate contained about 70% of the total 14C, and a compound co-chromatographing with phaseic acid contained over half of the remainder. At a low balancing pressure (1 MPa), release of 14C into the exudate was increased by N stress, prior water stress, and leaf aging. Kinetin did not affect 14C release in leaves of any age, N status, or water status. Distribution of ABA between pools can account in part for the effects of water stress, N stress, and leaf age on stomatal behavior, but in the cases of water stress and N stress there are additional kinetinreversible effects, presumably at the guard cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00394770
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