No abstract

Using the simple serial dilution technique, five strains of actinomycetes were isolated from nodules of Casuarina equisetifolia. In spite of the fact that these strains did not nodulate the host plant, they were assumed to belong to the genus Frankia because they possessed the morphological and cultural characteristics now admitted as specific to this genus.

SummaryField and cylinder experiments conducted in France and in Senegal showed that polyacrylamide, previously proposed as an entrapping gel for preparing Rhizobium inoculants, could be replaced by alginate (AER inoculant) or a mixture of xanthan and carob gum (XER inoculant). Semi-dried or dried AER and XER were used successfully provided that their storage time was less than 90 days. In soil inoculation trials, no marked differences were observed among semi-dried XER, dried AER, and dried XER. A number of seed inoculation experiments indicated that dried XER significantly outranked AER. Seeds preinoculated by up to 48 days with XER yielded plants which were comparable in nodulation and growth parameters to those derived from plant receiving peat inoculation at the time of planting.

No abstract

Attempting to isolate Frankia from Casuarina, we found that this endophyte exhibited two unexpected characteristics: (i) an inability of most infected nodule cells to produce Frankia colonies; and (ii) the absence of specific nutritional requirements in the isolation medium. These findings led us to the formulation of some principles for isolating Frankia from Casuarina.