Gibberellin Produced in the Cotyledon Is Required for Cell Division during Tissue Reunion in the Cortex of Cut Cucumber and Tomato Hypocotyls1
AUTOR(ES)
Asahina, Masashi
FONTE
American Society of Plant Physiologists
RESUMO
Cucumber (Cucumis sativus) hypocotyls were cut to one-half of their diameter transversely, and morphological and histochemical analyses of the process of tissue reunion in the cortex were performed. Cell division in the cortex commenced 3 d after cutting, and the cortex was nearly fully united within 7 d. 4′,6-Diamidino-2-phenylindole staining and 5-bromo-2′-deoxyuridine labeling experiments indicate that nDNA synthesis occurred during this process. In addition, specific accumulation of pectic substances was observed in the cell wall of attached cells in the reunion region of the cortex. Cell division during tissue reunion was strongly inhibited when the cotyledon was removed. This inhibition was reversed by applying gibberellin (GA, 10−4 m GA3) to the apical tip of the cotyledon-less plant. Supporting this observation, cell division in the cortex was inhibited by treatment of the cotyledon with 10−4 m uniconazole-P (an inhibitor of GA biosynthesis), and this inhibition was also reversed by simultaneous application of GA. In contrast to the essential role of cotyledon, normal tissue reunion in cut hypocotyls was still observed when the shoot apex was removed. The requirement of GA for tissue reunion in cut hypocotyls was also evident in the GA-deficient gib-1 mutant of tomato (Lycopersicon esculentum). Our results suggest that GA, possibly produced in cotyledons, is essential for cell division in reuniting cortex of cut hypocotyls.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=155884Documentos Relacionados
- Characterization of a Tomato Xyloglucan Endotransglycosylase Gene That Is Down-Regulated by Auxin in Etiolated Hypocotyls1
- In Vitro Gibberellin A4 Binding to Extracts of Cucumber Hypocotyls 1
- CsAGP1, a Gibberellin-Responsive Gene from Cucumber Hypocotyls, Encodes a Classical Arabinogalactan Protein and Is Involved in Stem Elongation
- ABP1 is required for organized cell elongation and division in Arabidopsis embryogenesis
- The Arabidopsis Gene Tardy Asynchronous Meiosis Is Required for the Normal Pace and Synchrony of Cell Division during Male Meiosis1