Article Contentsp. S1p. S2p. [S3]p. [S4]p. S5p. S6p. [S7]p. S8p. S9Issue Table of ContentsTransactions of the American Mathematical Society, Vol. 64, No. 3 (Nov., 1948), pp. 409-596Front MatterSymbiotic Nitrogen Fixation in Actinomycete-Nodulated Plants. Preface [pp. i-ii]Symbiotic Nitrogen Fixation in Actinomycete-Nodulated Plants. Program [pp. iii-v]Root Hair Infection in Actinomycete-Induced Root Nodule Initiation in Casuarina, Myrica, and Comptonia [pp. S1-S9]Early Nodule Development in Myrica gale [pp. S10-S14]Ultrastructure of the Nitrogen-Fixing Symbiont of Myrica pensylvanica L. (Bayberry) Root Nodules [pp. S15-S21]Morphogenesis and Fine Structure of the Actinomycetous Endophyte of Nitrogen-Fixing Root Nodules of Comptonia peregrina [pp. S22-S34]Immunological and Ultrastructural Demonstration of Nodulation of the European Alnus glutinosa (L.) Gaertn. Host Plant by an Actinomycetal Isolate from the North American Comptonia peregrina (L.) Coult. Root Nodule [pp. S35-S43]Relationship of Ultrastructure to Acetylene Reduction (N Fixation) in Root Nodules of Casuarina [pp. S44-S48]Separation of Actinomycete Nodule Endophytes from Crushed Nodule Suspensions by Sephadex Fractionation [pp. S49-S51]Hormones in Plants Bearing Actinomycete Nodules [pp. S52-S57]The Effect of Temperature on N Fixation (CH Reduction) by Nodules of Legume and Actinomycete-Nodulated Woody Species [pp. S58-S64]Nitrogen Isotope Distribution as a Presumptive Indicator of Nitrogen Fixation [pp. S65-S69]Nitrogen Fixation in Relation to Photosynthesis in Alnus glutinosa [pp. S70-S75]Utilizing N-Fixing Woody Plant Species for Distressed Soils and the Effect of Lime on Survival [pp. S76-S81]The Effect of Excess Soil Copper on the Growth of Black Spruce and Green Alder Seedlings [pp. S82-S87]Potential Uses of Nitrogen-Fixing Trees and Shrubs in Commercial Forestry [pp. S88-S90]Ecological Importance of Actinomycete-Nodulated Plants in the Western United States [pp. S91-S96]Growth and Nitrogen Relations of Coppiced Black Cottonwood and Red Alder in Pure and Mixed Plantings [pp. S97-S101]Crop Rotation of Douglas-Fir and Red Alder: A Preliminary Biological and Economic Assessment [pp. S102-S107]Comparative Growth of Pitch and Japanese Black Pine in Clumps of the N-Fixing Shrub, Bayberry [pp. S108-S109]Autumn-Olive as a Nurse Plant for Black Walnut [pp. S110-S114]Vesicular-Arbuscular Mycorrhizae Associated with Actinomycete-Nodulated Shrubs, Cercocarpus montanus Raf. and Purshia tridentata (Pursh) DC. [pp. S115-S119]Toward Development of Optimal Alnus glutinosa Symbioses [pp. S120-S126]Back MatterRoot Hair Infection in Actinomycete-Induced Root Nodule Initiation in Casuarina, Myrica, andComptoniaAuthor(s): Dale Callaham, William Newcomb, John G. Torrey, R. L. PetersonSource: Botanical Gazette, Vol. 140, Supplement: Symbiotic Nitrogen Fixation inActinomycete-Nodulated Plants (Mar., 1979), pp. S1-S9Published by: The University of Chicago PressStable URL: http://www.jstor.org/stable/2474196 .Accessed: 30/08/2011 15:59Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jspJSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact [email protected] University of Chicago Press is collaborating with JSTOR to digitize, preserve and extend access toBotanical Gazette.http://www.jstor.orgBOT. GAZ. 14O(SUPP1.): S1-S9. 1979. (¢ 1979 by The University of Chicago. 0006-8071/79/40OS-0001$00.88 ROOT HAIR INFECTION IN ACTINOMYCETE-INDUCED ROOT NODULE INITIATION IN CASUARINA, MYRICA, AND COMPTONIA DALE CALLAHAM,1* WILLIAM NEWCOMB,2t JOHN G. TORREY,* AND R. L. PETERSONt *Cabot Foundation, Harvard University, Petersham, Massachusetts 01366, and tDepartment of Botany and Genetics University of Guelph, Guelph, Ontario, Canada N1G 2W1 The infection process leading to the development of root nodules of Comptonia peregrina, Casuarina cunninghamiana, Myrica gale, and M. cerifera was studied by light and electron microscopy. Deformed growth of root hairs was observed as early as 24 h after seedlings grown aeroponically or hydroponically were inoculated with suspensions of crushed nodules or cultures of the actinomycetous endophyte of Comp- tonia. The extent of root hair deforIrJation showed a positive correlation with the number of nodules which subsequently developed. The essential features of infection in each of these species were very similar. The actinomycete entered a deformed root hair of the host in a region of folding of the cell wall. A convoluted elaboration of the root hair wall which occurred at this presumptive penetration site was continuous with the more evenly deposited capsule of the endophytic actinomycete. An associated feature of this wall deposi- tion was thickening of the cell wall of the infected root hair and the adjacent prenodular cells. The actino- mycete encapsulation was thickest at the presumed site of penetration and thinner in later stages of endo- phytic growth away from this site. These observations suggest a period of initial disequilibrium caused by the infection, followed by more harmonious symbiotic growth. The observation of a morphologically and cytologically similar root hair infection process in these three genera indicates that root hair infection involves a specific and orderly interaction which represents the common mode of invasion in the initiation of actinomycete-induced root nodules. Introduction The development of actinomycete-induced nod- ules on the roots of certain woody dicots represents a complex series of events. Three major stages in development can be distinguished: the infection of the root hair, the induction and invasion of a prenodular proliferation of the cortex, and the induction and invasion of primary and higher-order nodule lobe primordia. The anatomical details of root nodule morphogenesis have become better understood with studies of this process in A Inus glutinosa (POMMER 1956; TAUBERT 1956; ANGULO CARMONA 1974), Casuarina cunninghamiana (TOR- REY 1976), Comptonia peregrina (BOWES, CALLAHAM, and TORREY 1977; CALLAHAM and TORREY 1977; NEWCOMB et al. 1978), and Myrica gale (FLETCHER 1955; TORREY and CALLAHAM