Aerial Nodules in Casuarina cunninghamiana.
A complete survey of La Réunion Island showed that, in 40- to 50-year-old Casuarina cunninghamiana plantations located in the northeast at an altitude above 400 m, some trees bore aerial nodules as high as 6 to 7 m up the trunk. The nodules exhibited a significant specific acetylene reduction by the ARA method (0.77 mumol of C(2)H(4) per h/g [dry weight] of nodule) at the time of sampling (June 1990). Aerial nodules were also found on a Casuarina glauca trunk. Preliminary observations show that anatomically aerial and underground nodules do not differ significantly. In addition to host plant genetic determinants, aerial nodule formation is assumed to require sufficient rainfall, an abundance of Frankia spp. in the soil and air, and rhytidome on the tree trunk.
Prin
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Biotechnologie des Symbioses Forestieres Tropicales (CTFT-Centre de Coopération Internationale en Recherche Agronomique pour le Développement [CIRAD]/ORSTOM), 45bis Av. de la Belle Gabrielle, 94736 Nogent-sur-Marne Cedex, and CTFT-CIRAD/Office National des Forêts, 7 Chemin de l'IRAT, Ligne Paradis, 97410 St.-Pierre, France.
Duhoux
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E
Diem
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HG
Roederer
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Y
Dommergues
Y R
YR