Abstract
BackgroundThe dormancy of Adansonia digitata seeds is well known. For propagation purposes, plenty of germination tests were conducted, however, rarely taking the ecology of baobab into account. Our main goal, therefore, is to identify the decisive natural trigger for breaking the dormancy. We therefore performed 31 different tests and their influence on the germination rate (time to germination and proportion of seeds germinating).ResultsThe highest germination rates were reached in the heat tests while elephant’s digestion seems to stimulate germination of Adansonia digitata only to a limited extent. The chalazal slit of the seed represents the primary site of water entry. Tannins concentrated in this region that are influenced by temperature play an important role for inhibiting the germination.ConclusionAs a result, the hypothesis is formulated that germination success strongly depends on heat, provoked by wildfires or prolonged exposition to the sun causing decomposition of tannins by high temperatures rather than on digestion.
Highlights
Seeds of Adansonia digitata L. (Malvaceae) possess a thick and firm testa
Seeds that were sowed without any treatment did not germinate, which again confirmed earlier results and can be explained by the dormancy of Adansonia digitata seeds and their thick testa of about 700 μm (Fig. 2a)
The treatment with HCL pH=2 as well as pH=3 for 1 or 2 h confirm a low germination rate (GR) generated through acid treatment (0–2%)
Summary
Seeds of Adansonia digitata L. (Malvaceae) possess a thick and firm testa. Protective tissues of large seeds are known to increase survival in fire-prone savanna (Gashaw and Michelsen 2002) but at the same time impede germination under normal conditions. Several authors carried out germination tests on A. digitata seeds for conservation purposes (Esenowo 1991; Johansson 1999; Razanameharizaka et al 2006; Niang et al 2015; El-bably and Rashed 2018). To this effect, Regarding the impact of heat, several studies included a seed treatment in cold, hot or even boiling water (Esenowo, 1991; Razanameharizaka et al 2006; Niang et al 2015) but only Johansson (1999) studied the influence of dry heat on germination applying temperatures of 100 °C and 250 °C only. We performed 31 different tests and their influence on the germination rate (time to germination and proportion of seeds germinating)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
