A new pollination system in non-cleistogamous species of Viola results from nyctinastic (night-closing) petal movements – A mixed outcrossing-selfing strategy
| Autor: | Jerzy Bohdanowicz, Grzegorz Migdałek, Aneta Słomka, Monika Kwiatkowska, Piotr Żabicki, Justyna Żabicka, Thomas Marcussen, Kevin R. Thiele, Marlena Cubała, Elżbieta Kuta |
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| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
Ecology Pollination biology chasmogamous flower structure Stamen Plant Science biology.organism_classification 010603 evolutionary biology 01 natural sciences stigma receptivity Viola banksii self-compatibility pollination system nyctinasty Pollinator Self-pollination Botany Nectar Petal Pollen tube Ecology Evolution Behavior and Systematics 010606 plant biology & botany |
| Zdroj: | Flora. 253:1-9 |
| ISSN: | 0367-2530 |
| Popis: | Viola banksii of the eastern Australian and Tasmanian sect. Erpetion produces exclusively chasmogamous flowers, unlike most other temperate taxa of Viola which additionally produce obligatory self-pollinated cleistogamous flowers. This study explored flower structure and nyctinastic flower movements (temporal flower closure), the correlation of the timing of nyctinastic movements with stigma receptivity, and self-compatibility of flowers. Petal movement in day/night cycles was documented by two cameras. Floral morphology, anther protuberance anatomy, stigma receptivity, and pollen tube growth were examined using scanning electron microscopy, fluorescent microscopy, histochemical and sectioning techniques. Diurnal petal movements that cause flowers to be open during the day and closed during the night were documented in V. banksii. Chasmogamous flower colour, fragrance, anterior petal venation, and the indurated green area at the base of the anterior petal are all likely to play roles for pollinator attraction. Unlike most other Viola species, the anther protuberances do not function as nectaries. The flowers offer pollinators no nectar reward. The short time of stigma receptivity (2–3 days) of individual flowers limits opportunities for insect visitation and cross-pollination. Night-closed flowers of V. banksii appear to facilitate self-pollination. Self-compatibility was confirmed by tracking the pollen tube growth from the stigma to the ovule in spontaneous and hand self-pollinated flowers. Over the floral phenological cycle, nyctinasty coincides in time with stigma receptivity and, hence, the ability of self-pollination. We discovered that the same chasmogamous flower of V. banksii can cross-pollinate while open during the day, but self-pollinate while closed during the night (i.e. acting as a cleistogamous-like flower). Several floral characters indicate that V. banksii exhibits a pollination deceit strategy. Such a pollination system has not been described elsewhere in Viola. |
| Databáze: | OpenAIRE |
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