Arbuscular Mycorrhiza and Water and Nutrient Supply Differently Impact Seedling Performance of Acquisitive and Conservative Dry Woodland Species

Abstract: 
Arbuscular mycorrhizal (AM) fungi are known to increase seedling survival and performance through enhancement of nutrient and water uptake. Acacia etbaica, Acacia senegal and Boswellia papyrifera dominate large areas in African drylands. We evaluated the effects of AM, soil and water availability on their seedling growth. The experiment was factorial and was set up in a greenhouse with and without AM, topsoil and subsoil, and four levels of water availability. AM symbiosis enhanced the acquisition of water and nutrients and increased gas exchange resulting in increased Acacia and Boswellia seedling biomass. The rapidly growing Acacias (acquisitive strategy) showed larger mycorrhizal benefit at higher water availability. The slowly growing Boswellia (conservative strategy), in contrast, showed larger mycorrhizal benefit at lower water availability: with its large coarse root and only few fine roots Boswellia benefits at low root density and resource availability as AM enlarges water and nutrient uptake capacity. This study suggests how acquisitive and conservative species of dry woodlands may benefit from AM in different ways and that inclusion of the mycorrhizal habit in trait-based approaches increases understanding of functional divergence of coexisting tree species.
Les champignons arbuscularmycorrhizal (AM) sont connus dans l’augmentation de la survie et de la performance des semis grâce à l’amélioration de l’absorption des éléments nutritifs et de l’eau. Acacia etbaica, Acacia senegal et Boswelliapapyrifera dominent de grandes surfaces dans les régions arides de l’Afrique. Nous avons évalué les effets del’AM, le sol et la disponibilité de l’eau sur la croissance de leur plantule. L’expérience a été factorielle et effectuée dans une serre avec et sans l’AM, la couche arable et le sous-sol, et quatre niveaux de disponibilité de l’eau. La symbiose d’AM a amélioré l’acquisition de l’eau et des nutriments et a accru l’échange de gaz résultant de la biomasse accrue des semis d’Acacia et de Boswellia. Les Acacias à croissance rapide (stratégie acquisitive) ont montré des avantages des mycorhizes plus importants à une plus grande disponibilité de l’eau. Le Boswellia à croissance lente (stratégie conservatrice), au contraire, a montré des avantages des mycorhizes plus importants pour une plus faible disponibilité de l’eau: avec sa large racine grossière et seulement quelques racines fines, Boswellia bénéficie de la faible densité des racines et la disponibilité des ressources telles que AM agrandit la capacité d’absorption des éléments nutritifs et de l’eau. Cette étude suggère comment les espèces acquisitives et conservatrices des forêts sèches peuvent bénéficier d’AM dans différentes manières et que l’inclusion de l’habitude des mycorhizes dans les approches fondées sur les traits augmente la compréhension de la divergence fonctionnelle des espèces d’arbres coexistantes.
Language: 
Extended abstracts submitted under Enhancing Natural Resource Management
Date of publication: 
2012
Country: 
Region Focus: 
North Africa
Collection: 
RUFORUM Conferences and Workshops
Agris Subject Categories: 
Licence conditions: 
Open Access
Access restriction: 
Form: 
Printed resource
Publisher: 
Notes: 

The 2012 RUFORUM Biennial Conference is the third in the series. The main objective of the Biennial conferences is to provide a platform for agricultural research for development stakeholders in Africa and beyond to actively exchange findings and experiences, while at the same time learning lessons towards improving performance of the agricultural sector and ultimately people’s livelihoods. The biennial conference is RUFORUM’s most comprehensive meeting for the diversity of stakeholers in agriculture. It is especially dedicated to graduate students and their supervisors, grantees in RUFORUM member universities and alumni. It is a platform for peer review, quality control, mentorship, networking and shared learning. The third Biennial Conference was attended by 657 participants.This record contains an extended abstract accepted under Enhancing Natural Resource Management