A rapid, quantitative stomatal bioassay was developed to test abscisic acid (ABA)-like inhibition of stomatal opening by ABA-conjugates in epidermal peels of Commelina communis L. The one-hour bioassay was sensitive to 0.02 $\mu$M (+)-S-ABA and was insensitive to 20 $\mu$M ($\pm$)-S-ABA-1-methyl ester, which is consistent with previous work. Replacement of the C-4$\sp\prime$ carbonyl on ABA with hydrazone conjugates rendered these ABA-conjugates ineffective in inhibiting stomatal opening. Competition assays between ABA and excess ABA-conjugates demonstrated that ABA-conjugates did not interfere with ABA inhibition of stomatal opening. Together, these findings demonstrate the unlikelihood of producing anti-idiotype antibodies against C-4$\sp\prime$-substituted ABA for identification of receptor(s) involved in stomatal closure. / In a separate study, the interactions of ABA, Ca$\sp{2+}$, and osmoticum on ABA accumulation, $\sp{35}$S-amino-acid accumulation and incorporation into protein and protein synthesis were investigated in "isolated" guard cells of Vicia faba L. The effects of eight permutations, $\pm$ ABA, $\pm$ Ca$\sp{2+}$ (EGTA) and $\pm$ osmoticum (mannitol), on $\sp{35}$S-protein synthesis were investigated during two one-hour radiolabelling periods: the first and the fifth hours of incubation. Guard cells were "isolated" by sonication of epidermal peels. Ca$\sp{2+}$ depletion (EGTA) and osmoticum inhibited ABA accumulation in guard cells. $\sp{35}$S-amino-acid accumulation was inhibited to $<$50% of control values by ABA during the first hour of incubation and to varying extents by ABA, Ca$\sp{2+}$ depletion and osmoticum during the fifth hour of incubation with combinations of effectors causing greater inhibition. Incorporation percentages were not significantly different between incubation conditions of the same time interval, indicating a correlation between $\sp{35}$S-amino-acid accumulation and incorporation into protein. Computer-assisted analysis of autoradiographs of $\sp{35}$S-proteins following separation by two-dimensional-micro-polyacrylamide-gel electrophoresis determined that changes in guard-cell $\sp{35}$S-protein profile were elicited by all three effectors and incubation duration. Although Ca$\sp{2+}$-dependent synthesis of proteins was discerned consistently during the fifth hour of incubations, Ca$\sp{2+}$-dependent synthesis of ABA-induced proteins was not discerned. ABA- and osmotic-induced synthesis of similar protein(s) was not discerned consistently during either radiolabelling period. These results are based on a conservative interpretation of changes in $\sp{35}$S-protein profiles that allowed for comparisons among all incubation conditions. / Source: Dissertation Abstracts International, Volume: 56-04, Section: B, page: 1770. / Major Professor: William H. Outlaw, Jr. / Thesis (Ph.D.)--The Florida State University, 1995.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77443 |
| Contributors | Hite, Daniel Russell., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 71 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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