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| Author(s): |
Yve Canaveze
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Botucatu. 2016-04-27. |
| Institution: | Universidade Estadual Paulista (Unesp). Instituto de Biociências. Botucatu |
| Defense date: | 2016-02-22 |
| Advisor: | Silvia Rodrigues Machado |
| Abstract | |
In this study, we evaluated different aspects of the laticifer differentiation. The intrusive growth (the capacity of grow penetrating the middle lamella that cements adjacent cells) and the inducing action of laticifers (the capacity of induced an adjacent cell to acquirer laticifer features) are exciting growth mechanisms that may occur in laticifers, but they are poorly understood. Ethylene and jasmonic acid are plant hormones released during the herbivory and may affect the differentiation of secretory structures related with plant defense, as laticifers and resin ducts. Using transmission electron microcopy conventional methods (for characterization of the cell ultrastructure), and immunocytochemistry (for detection of the cell wall compounds), we explored the development of the articulated anastomosing laticifers with intrusive growth and the induction action of laticifer in the mature embryo and plant of Tabernaemontana catharinensis A.DC. (Apocynaceae). Additionally, we sprayed solutions of the 2% ethephon, 0.1% jasmonic acid and deonized water in plants of T. catharinensis (n = 33) growing under controlled conditions and evaluated the influence of these plant regulators on laticifer differentiation in the primary tissues and secondary phloem. In the ultrastructure, we verified that the process of cell incorporation within the laticifer system is distinct in the embryo and plant. However, in both the cases the protoplast of the incorporated cells acquires similar features of laticifers, and the incorporation is restricted to those cells in contact with laticifers. The immunolocalization analyses revealed that walls of laticifers and ground meristem cells in the mature embryo have similar labeled for JIM7 and JIM5 (homogacturonans with high and low degree of methyl-esterification, respectively), LM6 ((1→5)-α-L-arabinans) and BS400-2 (calose). In undifferentiated portions of the plant shoot apex, the laticifer walls show more intense labeling for JIM5 and LM6 and exhibit weak or no labeling for LM5 ((1→4)-β-D-galactans) and BS400-2 than the adjacent meristematic cells. The labeling of glycan epitopes in the shoot apex of plant is compatible with intrusive growth in laticifers. Quantitative analyzes revealed that the differentiation of laticifers from ground meristem (in cortex and pith) is reduced by exogenous ethylene, while jasmonic acid appears not to influence on the laticifer differentiation. Laticifer differentiation from procambium and vascular cambium seems be not influenced by ethylene or jasmonic acid. Thus, considering the protective latex functions, we suggest that the negative effect of exogenous ethylene on laticifer differentiation in T. catharinensis would make the plants most vulnerable to attack by herbivores and pathogens. (AU) | |
| FAPESP's process: | 12/16441-3 - Differentiation of articulated laticifers in Tabernaemontana catharinensis (Apocynaceae) |
| Grantee: | Yve Canaveze |
| Support Opportunities: | Scholarships in Brazil - Doctorate |