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| Author(s): |
Livia Camilla Trevisan Scorza
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2011-07-02 |
| Examining board members: |
Marcelo Carnier Dornelas;
Sandra Maria Carmello Guerreiro;
Silvia Rodrigues Machado
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| Advisor: | Marcelo Carnier Dornelas |
| Abstract | |
Rapid movements in plants are induced by mechanical stimuli and have originated in response to evolutionary adaptation to environmental stimuli that require fast responses by the plant. The androgynophore of some species of genus Passiflora, subgenus Decaloba, section Xerogona as P. sanguinolenta, P. citrina, P. capsularis e P. rubra exhibit a bending movement when touched. The aim of this work was to characterize this thigmotropic response. The movement takes place only when the androgynophore column or the ovary is stimulated and it always occurs in the same direction of the stimulus. If a new stimulus is applied right after the bending in the same direction that provoked this previous movement, the androgynophore is incapable to respond. Only after 2 to 3 minutes the androgynophore is able to react to a new stimulus in the same direction. The duration of the bending movement ranged from 1,5 to 2 seconds and the speed from 0,03 to 0,14 rad/s, being P. sanguinlenta and P. capsularis the fastest ones and P. citrina the slower one. Anatomical and ultrastructural analysis revealed that the movement is caused by loss of turgor from part of the parenchyma cells of the androgynophore. This partial and temporary plasmolysis is probably due to vacuolar reorganization, which seems to be reasonable, since there is a recovery of cell turgor, making possible a new stimulus in the same direction after a few minutes to produce new movement. When auxin or and inhibitor of its synthesis were applied to P. sanguinolenta flowers, we observed a fastest androgynophore bending movement. The mechanisms that lead to the movement in these Xerogona species seems to be similar to those observed in the pulvinus of some Leguminosae species. (AU) | |