Early Nodule Development in Myrica gale

Seedlings of Myrica gale were grown aeroponically and inoculated with suspensions prepared from mature nodules of M gale plants or with a homogenized preparation of a pure culture of the actinomycete isolated from Comptonia nodules. Morphological, anatomical, and cytological studies were made of early nodule development in these plants, and comparisons were made with similar stages in Comptonia and Casuarina Root hair infection was followed by prenodule formation in a manner similar to that in Comptonia In M. gale, most nodules originated with one or two primary nodule lobes. Thereafter, secondary nodule lobes formed sparsely and in a precisely ordered sequence. In 3-mo-old seedlings, nodules with up to five nodule lobes were observed, but the majority of nodules at this age were still one-to-three lobed In Comptonia the number of primary nodule lobes is much higher than in M. gale. In M. gale nodule roots developed from many but not all nodule lobes, usually in an ordered sequence.