A new type of epicotyl dormancy in crypto-viviparous fruits of Aegiceras corniculatum (Primulaceae), the first report from a true mangrove species

Background and aims – Although viviparous seeds of mangrove species have traditionally been considered non-dormant, our previous study has shown that Aegiceras corniculatum, a crypto-vivipary species exhibits epicotyl dormancy. However, the kind of epicotyl dormancy in this species has not yet been...

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Main Authors: Malaka Madhuranga Wijayasinghe, Kariyawasam Marthinna Gamage Gehan Jayasuriya, Savitri Gunatilleke, Nimal Gunatilleke, Jeffrey Walck
Format: Article
Language:English
Published: Meise Botanic Garden 2025-07-01
Series:Plant Ecology and Evolution
Online Access:https://plecevo.eu/article/151630/download/pdf/
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Summary:Background and aims – Although viviparous seeds of mangrove species have traditionally been considered non-dormant, our previous study has shown that Aegiceras corniculatum, a crypto-vivipary species exhibits epicotyl dormancy. However, the kind of epicotyl dormancy in this species has not yet been explored. Thus, the aim of this study was to ascertain the kinds of epicotyl dormancy present in A. corniculatum. Material and methods – Mature fruits were collected in Sri Lanka. The effects of scarification, light, and temperature on root emergence and the effects of scarification, gibberellic acid (GA3), salinity, light, and root stability on shoot emergence were tested. In addition, the morphology and anatomy of the fruits in relation to shoot emergence and growth were documented. Key results – Under both light/dark and darkness, > 70% of non-scarified and scarified fruits had an emerged root within 30 days, and thus, we considered them non-dormant. Root emergence was dependent on temperature, with reduced root emergence at higher temperatures. In contrast, a substantial time delay occurred between root and shoot emergence. Environmental conditions influenced shoot emergence, with emergence slower (1) in low NaCl solutions than in high solutions, (2) in darkness than in light/dark, and (3) when fruits were laid horizontally on a substratum as compared to being planted vertically. When fruits were treated with GA3 or were scarified, the time delay between root and shoot emergence was shortened. Conclusion – Since fruits of A. corniculatum contain a fully developed embryo, we conclude that they exhibit epicotyl physiological dormancy (PD). Furthermore, we propose that this dormancy represents a new type of epicotyl PD, symbolized by the formula: Ccry(root)-C1bp(shoot), where “cry” depicts the crypto-viviparous nature of the radicle or the hypocotyl.
ISSN:2032-3921