Behavior of Opuntia ficus-indica (L.) Mill. Heat-Stressed Microspores Under In Vitro Culture Conditions as Evidenced by Microscopic Analysis

Autor: Badra Bouamama-Gzara, Nejia Zoghlami, Samia Gandoura, Marianne Arnold, Hassène Zemni, Abdelwahed Ghorbel, Ahmed Mliki
Rok vydání: 2019
Předmět:
Zdroj: In Vitro Cellular & Developmental Biology - Plant. 56:122-133
ISSN: 1475-2689
1054-5476
DOI: 10.1007/s11627-019-10032-4
Popis: When constrained by in vitro culture conditions, microspores from Opuntia ficus-indica (L.) Mill. (Barbary fig) anthers were forced to stall out their gametophytic pathway and switch towards androgenesis. Five microspore stages were characterized based on cellular architecture. A relationship was also established between anthers and bud flower features. Anthers were cultured on three culture media containing 2,4-dichlorophenoxyacetic acid, thidiazuron and gibberellic acid at 22°C for 4 wk, followed by heat shock treatment at 32°C or 42°C for 2 wk, and the stressed material was recultured at 22°C for 24 wk in the dark. When anthers were heat shocked at 32°C and 42°C, the cultivated anthers swelled and burst, followed by the microspores flowing onto the explant surface. Androgenesis occurred directly and indirectly at uni- and binucleate stages. The micromorphology of multicellular, proembryos, globular, torpedo and cotyledonary-like-shaped structures from dehisced anthers was confirmed by environmental scanning electron microscopy. Furthermore, at 42°C, microscopic analysis demonstrated that the non-responsive microspores achieved pollen maturation and more rarely, the emission of a pollen tube. However, 11.4 to 14.4% of the mature pollen grains were converted into pollen embryos. The established system may serve, for the first time, as a protocol to produce microspore embryos in O. ficus-indica. Nevertheless, more efforts are needed to complete the development of diplo-haploid plantlets.
Databáze: OpenAIRE
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