ROOT NODULES IN THE GENUS COLLETIA

Abstract

SUMMARYFollowing the earlier reported detection of root nodules on a species of Colletia growing in the Glasgow Botanic Gardens, the authors' enquiries have revealed that Colletta species are nodulated in some other botanic gardens, both in Europe and elsewhere. Cytological study of the nodules under the electron microscope shows that the endophyte is a procaryotic actmomycete-like organism consisting of septate, branching hyphae which are 0-37 to 0-53 fim in diameter and form terminal spherical vesicles 2-0 to 2-5 fim in diameter. The vesicles are internally sub-divided and lie peripherally within the host cell. The endophyte ,s enclosed withm a thin layer (or capsule) of material which judging by previous studies of other non-legume nodules consists of carbohydrate-related substances laid down by the host cytoplasm. Data froni long-term growth trials and acetylene assays show that Colletia nodules are nitrogen-fixing and capable of satisfying the nitrogen-needs of the host plant. Of the five genera of the Rhamnaceae that have so far been found to be nodule-bearing, four (namely Colletta, Dtscaria, Trevoa and Takuenea) are in the tribe Colletieae, while the fifth genus (Ceanothus) is placed elsewhere in the family by taxonomists. A very similar situation exists in the Rosaceae as regards the distribution of nodulating genera and species. It is concluded that in these families the habit of symbiosis with a nitrogen-fixing actinomycete probably arose, in some instances, prior to the establishment of now-existing genera, but in others at a later stage. This conclusion is consistent with the belief that nodule symbioses were initiated in an earlier era when plants in general were subject to nitrogen stress.

Isolation of Frankia from nodules of Trevoa trinervis: ultrastructural characterization

“…Actinorhizal plants native to Chile and South America are found in the families Rhamnaceae and Coriariaceae. The seven genera comprising the family Rhamnaceae (Trevoa, Retanilla, Discaria, Talguenea, Colletia, Ceanothus, and Kentrothamus) have been reported to bear actinorhizal nodules (Medan and Tortosa 1976, 198 1 ;Quispel 1979;Bond and Becking 1982;Abarzua and Longeri 1988;Balboa et al 1988). Trevoa trinervis is a n important matorral shrub, characterized by its fast growth o n disturbed sites and for its nitrogen-fixing capacity (Rundel and Nee1 1978;Silvester et al 1985).…”

TheParasponia parviflora—Rhizobium symbiosis. Host specificity, growth and nitrogen fixation under various conditions

“…(5) Rhizobium ]aponicum (10): R87, R88, R89, R90, R95, R109, R114, RCC 705, RCC 707 and RCC 711. (6) Rhizobium lupini (7): R18, R61, R92, R129, R130 R131, R138 from Lupinus sp. (lupine), and R26 from Ornithopus sp.…”

“…However, with many strains a kind of pseudo-root nodules were produced by extensive callus formation along the root (Plate 1D and E). (6) Rhizobiurn lupini Seven strains were tested, six of them (including the Serradella strain R26) produced root nodulation. The negative strain was R18.…”

Characterization of native Frankia strains isolated from chilean shrubs (Rhamnaceae)

“…Actinorhizal plants are found in the family Rhamnaceae, that comprises seven genera (Trevoa, Retanilla, Discaria, Talguenea, Colletia, Ceanothus, and Kentrothamus) which are known to bear root nodules of Frankia and to have the capacity to fix atmospheric nitrogen (Bond and Becking, 1982;Delwiche et al, 1965;Medan and Tortosa, 1976;Rundel and Neel, 1978;Silvester et al, 1985).…”