Plant and Soil 254: 329–335, 2003.
© 2003 Kluwer Academic Publishers. Printed in the Netherlands.
Growth of micropropagated bananas colonized by root-organ culture
produced arbuscular mycorrhizal fungi entrapped in Ca- alginate beads
& S. Declerck
Departamento de Protecci´on Vegetal, Instituto Canario de Investigaciones Agrarias, (I.C.I.A.), Apdo. 60.
38200 La Laguna, Canary Islands, Spain.
Universit´e catholique de Louvain, Mycoth`eque de l’Universit´e cath-
olique de Louvain (MUCL
), Unit´e de Microbiologie, 3 Place Croix du Sud, 1348 Louvain-la-Neuve, Belgium.
Received 20 August 2002. Accepted in revised form 19 February 2003
Key words: alginate, arbuscular mycorrhizal fungi, banana, micropropagation, root-organ culture
The effect of root-organ culture (ROC) produced arbuscular mycorrhizal fungi (AMF), i.e. Glomus proliferum,
Glomus versiforme and Glomus intraradices, entrapped in Ca-alginate beads on the ﬁrst stages development of
micropropagated bananas (Musa spp. cv. Grande Naine) was investigated. The experimental design consisted of
banana plants inoculated with one of the three AMF and two controls, i.e. Control-AL (with empty alginate beads),
and Control (no beads). Forty plants were considered per treatment and cultured under greenhouse conditions
in a completely randomized design. Eight plants per treatment were harvested 40, 80, 120, 160 and 200 days
after inoculation and analysed for root colonization, growth parameters and nutrient concentration. In addition,
spores were enumerated in the substrate at the same intervals. Ca-alginate entrapped ROC-produced AMF spores
were able (1) to colonize the root system of a micropropagated banana cultivar under nursery conditions, (2)
to increase plant P nutrition and biomass, and (3) to proliferate in the commercial nursery substrate, therefore
increasing the fungal inoculum biomass. The entrapment of ROC-propagated spores, adaptable to a wide range of
Glomeromycetes, represents thus a forthcoming alternative pathogen-free inoculum.
Micropropagation is nowadays a successful technique
for mass-production of plants for research and com-
mercial purposes (Nowak, 1998). Among the plants
currently propagated in vitro, bananas are increasingly
replacing conventional planting material for the estab-
lishment of new or replacement of existing plantations.
The reasons for using such material are the rapid
production of high quality, disease-free, and uniform
plants. However, micropropagated plants are also free
of any beneﬁcial microbial inhabitants of roots such
as arbuscular mycorrhizal fungi (AMF). These sym-
biotic organisms are known to improve plant growth
FAX No: 10-451501.
Part of the Belgian Coordinated Collections of Micro-
and performance under environmental stress condi-
tions (Smith and Read, 1997) and may facilitate plant
adaptation to nursery (reviewed by Rai, 2001).
Early mycorrhiza inoculation during the weaning
phase of micropropagated plantlets, is beneﬁcial to
several tropical species, such as papaya, avocado,
pineapple (Jaizme-Vega and Azcón, 1991), and ba-
nana (Declerck et al., 1995; Jaizme-Vega and Azcón,
1995; Jaizme-Vega et al., 2002; Yano-Melo et al.,
1999). Various sources of pot-, hydro-, and aeroponic
inoculum i.e. spore, colonized roots, rhizospheric
soil, have been used successfully. The use of an in
vitro root-organ culture (ROC) technique (Fortin et al.,
2002) for the production of AMF inocula is another
option compatible with plant micropropagation (De-
clerck et al., 2002). Recently Moutoglis and Béland
(2001) provided an overview of the potential tech-