ROOT-NODULE SYMBIOSIS BETWEEN RHIZOBIUM AND PARASPONIA (ULMACEAE)

Evidence of root nodulation and N2 fixation by Parasponia parviflora Miq. found earlier by Akkermans et al.1, 2 was confirmed, although with a lower value for N2 fixation. In contrast to the above-mentioned investigation, the Parasponia trees examined in the present study were growing under natural conditions. The evidence giving by Akkermans et al.1, 2, that Trinick's Trema is a Parasponia species was confirmed by cytological and structural studies of Parasponia root nodules, which resembled closely the 'Trema' root nodules of Trinick19. Moreover, evidence was obtained that Trema cannabina Lour. growing in natural habitat on Java and two imported, hitherto unexamined, Trema species (T. micrantha and T. guineensis) bore no root nodules. Isolates from Parasponia parviflora root nodules produced effective root nodules both in sterile Parasponia seedlings and sterile Vigna unguiculata (cowpea) and Macroptilium atropurpureum plants confirming their identity as Rhizobium. © 1979 Martinus Nijhoff.