Fleshy Roots Research Articles

Status and Relationships of the Chinese Endemic Platycraspedum (Brassicaceae)

The generic limits and relationships of Platycraspedum are discussed, and the new species P wuchengyii is described. It is most closely related to Taphrospermum, from which it differs by having toothed filaments of median stamens, 2-lobed stigmas, palmately veined leaves, unequal sepals, and minutely reticulate seeds. As delimited here, Platycraspedum O. E. Schulz consists of two Chinese species endemic to eastern Xizang (Tibet) and neighboring Sichuan. Schulz (1922) compared the generic type, P tibeticum, with Dilophia Thomson and later (Schulz, 1936) placed both genera in the tribe Lepidieae. However, Platycraspedum does not have angustiseptate fruits, a feature Schulz (1936) used primarily to define the limits of Lepidieae. In our opinion, Platycraspedum, along with Dilophia, Taphrospermum C. A. Meyer, Lignariella Baehni, and several other genera, should be closely associated with Cardamine L., all of which share flattened replums, a feature very rare elsewhere in the Brassicaceae. The present paper does not aim to present the tribal alignments of these genera; nonetheless Schulz's (1936) placement of Platycraspedum in the Lepidieae is unwarranted. Platycraspedum is most closely related to Taphrospermum, a genus of seven species (Al-Shehbaz, unpublished) distributed primarily in' China. Both genera have fleshy fusiform roots, a whorl of scalelike leaves at the root base, petiolate cauline leaves, bracteate inflorescences, white petals, basally dilated median filaments, and flattened replums. Platycraspedum is readily separated from Taphrospermum by its palmately veined cauline leaves and bracts, minutely reticulate seeds, strongly flattened and toothed median staminal filaments, unequal sepals with the lateral pair saccate, poorly developed lateral nectaries with the median ones lacking, and 2-lobed stigmas. By contrast, Taphrospermum has pinnately veined cauline leaves and bracts, foveolate or rarely papillate seeds, terete and toothless filaments, equal and nonsaccate sepals, well-developed annular lateral nectaries confluent with median ones, and entire stigmas. Platycraspedum can easily be confused with some species of Eutrema R. Brown sect. Wasabia (Matsumura) 0. E. Schulz, but it can be separated by its strongly flattened and 1-toothed median filaments, flattened replums, non-mucronate leaf teeth, subsessile fruits, unequal sepals with the inner pair saccate, 2-lobed stigmas, and lack of septa. Eutrema has slender and toothless median filaments, terete replums, mucronate teeth or leaf-vein endings, stipitate fruits, equal sepals with the inner NOVON 10: 1-3. 2000. This content downloaded from 157.55.39.78 on Sun, 19 Jun 2016 06:11:43 UTC All use subject to http://about.jstor.org/terms

Inflorescence Removal Effects on Root Yield of American Ginseng (Panax quiquefolium L.)

American ginseng is a perennial herbaceous plant grown for its fleshy root and seeds. Little is known about fruit set and development in ginseng. In commercial practice a small proportion of 2-year-old plants may bear flowers and seed but these seeds usually are not harvested. Seeds from 3-year-old plants are harvested and used for establishing plantings, but seed from 4-year-old plants, if available, are preferred. Some growers remove flowers manually from plants in June at an estimated cost of $2500 per ha and claim higher root yields. The objective of this work was to determine the effect of inflorescence removal in 1 or 2 years on root yield. Manual removal of inflorescences from mature (3-and 4-year old) American ginseng plants at commercial timing (early July, ≈25% flowers open) increased root yield at harvest compared to plants where the inflorescences were retained. Consecutive inflorescence removal for 2 years (3rd and 4th) increased yields 55.6% compared to 34.4% for removal in one year only (4th). Root size distribution analysis showed that most roots (≈40%) were in the medium category (10–20g): inflorescence removal did not influence root size distribution. Root yield for 3-year-old plants increased quadratically with plant density with plants lacking inflorescences having an estimated yield increase of 25%. Maximum yields of 2.4 kg·m–2 for deflowered plants were suggested at a plant density of 170 plants/m2. To maximize ginseng root yield all plants should have inflorescences removed except those needed to provide seed for future plantings.

Genotypic Variations in Quality and Shelf-Life of Fresh Roots of Philippine Sweet Potato Grown in Two Planting Seasons

Sweet potato breeding in the Philippines has recently integrated root quality and shelf-life attributes in varietal development. In this study, the harvest and post-harvest quality of the fleshy roots of different sweet potato genotypes were determined. These genotypes included the existing recommended varieties and the elite selections from the polycross breeding nursery and were grown during the dry and wet planting seasons. Dry matter, starch, sugar and protein contents of freshly harvested roots were found to differ widely with genotype. During storage at ambient temperatures, starch content decreased, sugar content increased and in some genotypes dry matter increased. Protein content of the stored roots varied only slightly from that of fresh roots. The different genotypes also differed in the degree of weight loss, shrivelling, decay and consequently, shelf-life. Some genotypes had short-lived roots (less than 1 month) while others had roots which were still marketable at the end of the 3-month storage period. Root quality and shelf-life similarly varied with planting season. Some genotypes had increased dry matter, starch and sugar contents and long shelf-life when planted in the dry season while others had these characteristics when produced in the wet months. Protein content generally decreased in wet-season-produced roots. However, a number of genotypes had comparable root quality and shelf-life regardless of planting season.

Respiration in a New Tuber Crop, Apios americana

The objective of this study was to investigate the respiratory pathways in the underground storage tissues (tubers, fleshy roots, and rhizomes) of Apios americana Medikus (apios). Freshly sliced tubers of experimental breeding lines expressed variable capacities for alternative respiration, depending on genetic background, although the alternative respiratory pathway was not engaged in any of the apios tissues tested. The capacity of the alternative pathway present upon slicing was consistent with genetic line over the 5 years of the study. Respiration patterns of tubers and fleshy roots were comparable within a genetic line; however, substantial differences were found in the respiration of the nonthickened sections of rhizomes compared with the storage tubers. Total respiration of stored rhizomes was high (up to 2.7 μl O2/g per rein) compared to that of tubers (up to 0.9 μl O2/g per min). Rhizome tissue respiration had a large capacity for alternative respiration (40%-60% of total respiration), while tuber tissue had 0% to 73% alternative respiration, depending on genetic source. Epidermal layers, obtained from tubers that lacked a capacity for alternative respiration after slicing, had alternative respiration rates comparable to those of rhizomes. Furthermore, the alternative pathway could be induced in these tubers through conventional aging techniques. Etiolated shoots and rhizomes growing from these tubers also had an alternative respiration capacity that was half of the total rate. These results demonstrate that, although the capacity for alternative respiration is present in tissues of apios, freshly sliced tubers may or may not exhibit this pathway depending on genetic background. This attribute maybe significant as apios undergoes further domestication.

A New Strain of Sweet Potato Feathery Mottle Virus That Causes Russet Crack on Fleshy Roots of Some Japanese Cultivars of Sweet Potato.

A new filamentous virus (designated VC) was isolated from sweet potato plants that seemed to be tolerant to russet crack. It infected Ipomoea spp., Chenopodium quinoa and C. amaranticolor. Ipomoea nil infected with the virus developed typical vein-clearing on the first true leaf. The infectivity of VC in sap was lost at dilutions between 1:10, 000 and 1:100, 000 and after storage for one day at 20°C. Its thermal inactivation point was between 50 and 60°, and virus particles were 850-880nm long and 13nm wide. VC was nonpersistently transmitted by the aphid Myzus persicae, and was serologically related but not identical to sweet potato feathery mottle virus (SPFMV, abbreviated as Mo) that belongs to Potyvirus. Coat proteins of both purified VC and Mo migrated as three major bands of proteins with Mr 32, 000, 30, 000 and 29, 000. However, electro-blot immunoassay revealed one major protein of Mr 38, 000 and an additional, more slowly migrating protein of Mr 97, 000 in leaves infected with VC, and one major protein of Mr 38, 000 in leaves infected with Mo. Sweet potato inoculated with VC developed symptoms of russet crack on the fleshy roots. These results indicate that VC is the causative agent of russet crack that occurs in some Japanese cultivars of sweet potato and that VC is a new strain of SPFMV. Therefore, we named VC and Mo severe strain (SPFMV-S) and ordinary strain (SPFMV-O), respectively, of SPFMV.

A Comparative Study of the Anchorage Systems of Himalayan BalsamImpatiens glanduliferaand Mature SunflowerHelianthus annuus

The anchorage systems of Himalayan balsam Impatiens glandulifera and mature sunflowers Helianthus annuus were investigated by combining morphological and anatomical study of the root systems with mechanical tests on roots and with studies in which mature plants were pulled over. The root system of balsam is dominated by large numbers of fleshy tapering adventitious roots which point downwards from their origin at the wide stem base. Sunflowers, in contrast, have a tapering tap-root from which 20–30 well-branched laterals emerge, pointing radially outwards and downwards. Roots of each species have contrasting anatomy: those of balsam resemble stems, having a central watery pith and being strengthened peripherally by lignification of vascular tissue; roots of sunflowers are strengthened by a solid woody stele. Roots of both species are rigid in tension and, towards the base, in bending. Both species exhibited similar behaviour to that known for trees such as Sitka spruce; when pulled over they rotated about a hinge leeward of the stem base and a root-soil ball was pulled out of the surrounding soil. Anchorage was resolved into three components which, in order of decreasing magnitude, were (i) the resistance to pulling of the roots on the windward side of the plant (and, for sunflower, the tap-root); (ii) the resistance of roots and soil at the leeward hinge to rotation; and (iii) the weight of the root-soil ball. Sunflower had stronger anchorage but achieved it at a greater cost in terms of the dry mass of its root system. In each species, the morphology, anatomy and mechanical properties of the root system can be related to those of the stem. The wide stem base of balsam allows large numbers of mechanically efficient fleshy roots to be attached whereas in sunflowers a woody tap-root system is necessary to anchor the much narrower stem.

Response ofCymbidium sinenseto drought stress

Cymbidium sinense was able to withstand severe drought. Drought resistance was managed through a variety of morphological and physiological adaptations. The plant possesses a fleshy root with velamen, a water-storing pseudobulb and special stomatal morphology. Even after 42 days of drought, when the soil water content had been reduced to 15% of maximum holding capacity, the water content in leaf, roots and pseudobulbs was 63-70%. Stomatal closure was observed when the leaf water potential was around — 1.05 M Pa. The plants were able to recover following watering after being subjected to drought for 42 days.

機械的に肥大を抑制したカブ肥大根の糖濃度について

Water accumulation of the roots was reduced by enclosing them within an acrylic sleeve thereby restricting lateral growth. This study was carried out to investigate how restricting the uptake of water by fleshy turnip roots affects the accumulation and the concentration of sugars of that organ.1. The sleeve reduced the volume of fleshy roots by 1/3 of that of the untreated roots. The dry matter, ethanol-insoluble solids, glucose and fructose contents expressed on a whole root basis were lower in the treated roots than in those of the control, but the level of sucrose in the treated and control roots was nearly equal. When the data are expressed on the ba-sis of water content in the roots, the growth restriction increased the concentrations of dry matter and sucrose but decreased those of glucose and fructose slightly. Hence, the total sugar concentrations of the treated and control roots were the same.2. Sucrose concentrations were not different among the tissues outside (phloem) and just inside (outer xylem) the lateral cambium and the central cortex which indicate that the re-striction of root volume did not increase sucrose concentration in a particular tissue.These results suggest that the accumulation of sugars depends on the accumulation of water in the fleshy turnip roots. Reasons why total sugar concentrations were not affected by the treatment are discussed in relation to sugar metabolism in the roots.

Ethylene production as a possible indicator of wound healing in roots of several sweet potato cultivars

Fleshy roots of 18 sweet potato cultivars were wounded and cured for 12 days. Significant differences were found between cultivars for ethylene production, cell lignification, and wound periderm formation. Average ethylene production, the number of days ethylene was produced, or the day of peak ethylene production showed nonsignificant and low (r2=0.40) correlations with cell lignification or wound periderm formation; however, multiple regression analysis indicated statistically significant and moderate correlations between selected daily ethylene production and cell lignification (r2=0.74) and wound periderm formation (r2=0.73). These observations suggest that measurement of ethylene produced by wounded sweet potato roots may be useful in helping screen large numbers of sweet potato breeding lines and their progeny for the ability to produce lignified and wound periderm cell layers. Wound healing, however, is only one aspect of good storage capability in sweet potato cultivars.

Survivorship of penstemon grandiflorus in an oak woodland: combined effects of fire and pocket gophers.

The effects of fire and pocket gophers, Geomys bursarius, on the survivorship of Penstemon grandiflorus growing in an oak woodland in Minnesota were studied from 1986 to 1990. Plants growing in sparse vegetation experienced mortality rates twice that of plants growing in dense vegetation. This difference was due partly to pocket gophers whose earth moving activities reduce the density of vegetation and bury and kill individual Penstemon plants. Laboratory feeding trials showed that gophers readily eat Penstemon, particularly the fleshy roots. An experiment involving the removal of 25-75% of the root tissue in 90 plants showed that root loss significantly reduced survivorship, suggesting that gopher herbivory might also kill plants. When gophers were experimentally excluded, plants growing in sparse vegetation exhibited significantly lower mortality rates than those growing in dense vegetation. Plants in the smallest size class exhibited reduced survivorship following a late spring burn; however, overall patterns of survivorship of plants in burned areas did not differ markedly from those in the unburned areas. A longitudenal analysis of plants with different reproductive histories revealed no survivorship cost to reproduction. Mortality rates decreased with increasing plant size. Small plants were more likely to be killed by fire and by being buried under gopher mounds. Differences in underground energy reserves of small and large plants can account for most of the survivorship patterns observed in this study. The study shows that within openings of the oak woodland, fire and gophers reduce the survival of individual Penstemon plants. Nevertheless, since both gophers and fire also serve to perpetuate suitable habitat in the woodland, Penstemon is ultimately dependent on both for its long term persistence in the landscape.

Sphagnum Peat in the Growing Medium and Nitrogen Application Influence Asparagus Growth

High levels of sphagnum peat in the growing medium promoted growth of asparagus (Asparagus officinalis L. cv. Viking 2K) in a greenhouse study. Application of NH4NO3 > 1 g/pot (84 kg·ha-1 equivalent) was detrimental to root growth. High N rates and high organic matter levels decreased fibrous root development. Shoot dry weight was highly correlated with fleshy root number, root dry weight, and shoot vigor.

Potential of Entomopathogenic Nematodes as Biological Control Agents of Sweetpotato Weevil (Coleoptera: Curculionidae)

The entomopathogenic nematodes Heterorhabditis bacteriophora Poinar (= H. heliothidis Khan, Brooks, & Hirschmann) (HP88 strain) and Steinernema (=Neoaplectana ) carpocapsae Weiser (All and G-13 strains) were evaluated as biological control agents of the sweet potato weevil, Cylas formicarius elegantulus (Summers). In Petri dish bioassays, all three strains were pathogenic to larvae and pupae of C. f. elegantulus . The LD50 values of C. f. elegantulus larvae were 2.6, 2.9, and 3.4 infective juveniles per insect for ‘All,’ ‘G-13,’ and ‘HP88,’ respectively. The LD50 values of pupae were 4.9, 5.9, and 4.8 infective juveniles per insect for these three nematodes, respectively. Virulence did not differ among strains or between life stages within each strain. Under simulated field conditions, ‘G-13’ was most efficacious at killing weevil larvae within infested sweet potato ( Ipomoea batatas (L.) Lam.) roots followed in decreasing order by ‘HP88’ and ‘All’ nematodes. Efficacy in killing pupae within roots did not differ among the three nematodes or between life stages for each nematode. Field applications of ‘HP88’ and ‘All’ nematodes were more effective than chemical insecticides at reducing weevil densities on plants. ‘HP88’ nematodes were more effective than ‘All’ nematodes and chemical insecticides at reducing weevil damage to fleshy roots.

SEASONAL CHANGES IN ASPARAGUS ROOT GROWTH IN CONVENTIONAL AND NOTILL SYSTEMS

Published data on the spatial patterns and periodicity of root growth in asparagus are limited. During the 1989 growing season growth and distribution of both fleshy and fibrous roots were monitored in a 7 year old asparagus planting. Soil cores were removed at 15 cm intervals to a depth of 90 cm at 40 and 80 cm from the plants in asparagus beds which had been maintained under conventional (CT) and no-till (NT) production systems. Fleshy and fine roots were separated from the soil and root length densities calculated. Harvests began in late March and continued at three week intervals until early November. Fine root growth was greater in the NT than CT in all depths and at both locations in March. Greatest lengths of fine roots were at the 15-60 cm depths for both CT and NT. This pattern was consistent throughout the season. Fine root lengths decreased by one half by the middle of the year (July) and remained at those levels until the last harvest (Nov). Fleshy root lengths were more variable, however NT generally had greater lengths than CT. Greatest length of fleshy roots were located in the 15-60 cm depths for both CT and NT treatments. Few fleshy roots were found below the 60 cm depth.

Influence of Dikegulac Sprays on Shoot Emergence and Growth of Asparagus

Abstract Spraying 9-month-old asparagus seedlings (Asparagus officinalis L.) with dikegulac-sodium (atrinal) solutions ranging from 0 to 500 ppm in 100-ppm increments increased the number of new shoots, particularly within the range of 300 to 500 ppm. The response was elicited 4 weeks after the treatment and continued thereafter over the 10 weeks, during which measurements were taken. Dikegulac did not affect the height or the fresh and dry weights of the plants for this first phase. Emergence of new shoots after the plants had been cut off was equally affected by dikegulac; 300 to 500 ppm was still the most effective. However, effectiveness was significant after 2 weeks. The height of plants was significantly reduced by the chemical, but the fresh and dry weights were not affected. At the third phase, none of the growth characteristics, including shoot emergence, was affected by the chemical. This lack of response may be attributable to the depletion of carbohydrate reserves in the fleshy roots. Chemical name used: 2,3:4,6-bis-O-(1-methylethylidene)-α-L-xylo-2-hexulofuranosonic acid (dikegulac).

Two New Species of Ceropegia (Asclepiadaceae: Stapelieae)

Summary. Two new species of Ceropegia, C. barbigera from Ethiopia and Somalia and C. poluniniana from the Himalaya of western Nepal are described and illustrated. Relationships with other species are discussed. Ceropegia barbigera Bruyns spec. nov. a C. galeata Huber lobis corollae non late galeiformibus, seriebus longitudinalibus papillarum in tumore basali tubi corollae differt; a C. arabica Huber lobis corollae brevibus truncatis facile distinguenda. Typus: Ethiopia, Lavranos & Gilbert 9241 (holotypus K). Sparsely branched, siucculent climber up to 1-5 m, arising from a cluster of white, fusiform, fleshy roots. Stem 3-4 mm thick, grey- to purplish-green, epidermis with fine, longitudinal, translucent, scabrous ridges, without hairs. Leaves up to 7 mm long, subulate, rapidly caducuous, only found near growing apex of stem, fleshy, with few, thick hairs near base, otherwise glabrous, with small, conical stipules. Inflorescence sessile or very shortly pedunculate, extra-axillary, 1-6-flowered, flowers sometimes opening simultaneously. Pedicel 5-6 mm long, 1-1-5 mm thick, glabrous. Sepals lanceolate, 4 mm long, 1 mm broad at base, glabrous. Corolla 30-45 mm long, outside glabrous, variously spotted with purple-brown on grey-white background; tube with inflated base 8-11 mm long, 8-10 mm diam., tapering off into calyx below and abruptly narrowing above into upper part of tube, inside without hairs, with longitudinal, pale-green ridges of papillae each tipped with brown, background colour whitish, upper part of tube projecting slightly into lower (projecting part green with dense covering of fine setae), 2-5-3 mm diam. at base, widening gradually to funnel-shaped mouth 8-12 mm broad, white with faint green stripes, with white hairs in mouth and up to third of way down tube; lobes marked as in Figure IG, 10-12 mm long, loosely connate at apex, margins tightly folded back in basal half, lobe tightly folded down midrib in upper half, apex truncate, large glabrous projection on inner surface, rest of inner face with purple-black to white hairs usually with submarginal cilia (each arising in a fine groove) along upper quarter. Corona translucent-white with purple-red blotches, glabrous; outer lobes 2-2-5 mm long, bifid in upper third into two round-tipped converging teeth; inner lobes linear, 2-5-3 mm long, incumbent on anthers, connate and rising up above centre of column, often diverging slightly at finely setulose apices. (Fig. 1).

Translocation and Fate of Dicamba, Picloram, and Triclopyr in Horsenettle,Solanum carolinense

Greenhouse studies were conducted to determine the extent of translocation from the foliage to fleshy roots, the inherent toxicity, and the fate of radiolabeled and nonlabeled dicamba, picloram, and triclopyr in horsenettle. Roots of horsenettle acted as the major sink for photosynthate accumulation at the 0.2- to 0.5-bloom growth stages as determined by autoradiography. Dicamba, picloram, and triclopyr were translocated into the roots of horsenettle and accumulation continued for at least 16 days.14C associated with each herbicide found in the roots ranged from 1.3% at 4 days to 3.8% at 16 days. After 16 days, slightly more14C from plants treated with dicamba and triclopyr (3.8 and 3.6%) than picloram (3.0%) was translocated to roots. These compounds were metabolized slowly in the foliage and roots as determined by thin-layer chromatography (TLC) and autoradiography. In translocation studies with horsenettle shoots, picloram at 1.12 kg/ha killed the treated and untreated shoots and roots. Dicamba and triclopyr at the highest rates killed the treated shoots and partially destroyed the root system. Symptoms were noted on the untreated shoots, but full recovery occurred at 8 weeks. Since each of the herbicides was metabolized slowly and only slight differences in their translocation were observed, the relatively higher herbicidal effectiveness of picloram must be attributed to its greater inherent potency.

Cylindrocarpon musae . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Cylindrocarpon musae . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Musa AAA (Cavendish). DISEASE: Rotting of fleshy roots and rhizomes of banana. GEOGRAPHICAL DISTRIBUTION: Asia: Philippines; North America: Costa Rica, Guadeloupe, Martinique, Panama; South America: Colombia, Ecuador. TRANSMISSION: The fungus probably survives as 'chlamydospores' in soil. Its slimy spores may be dispersed by water. Long distance spread may potentially occur by transportation of infected plant material or contaminated soil.

The Crop Potential of Apios americana—Preliminary Evaluations

Abstract Apios americana Medikus, a nitrogen-fixing, viny legume that produces seeds and tubers is being evaluated as a food crop. About 2500 plants obtained from colchicine-treated and nontreated seeds, tubers from wild sites, and plants derived from tissue culture were cultivated on a silt loam soil. Two tuber-derived plants (probable clone) yielded an average of 3.747 kg and another seed-produced plant yielded 2.170 kg of tubers per plant. Plants were also found that produced mostly rhizomatous material without tubers, only fleshy roots, fleshy roots and tubers, and only tubers. More than 400 pods per plant were observed from some plants, although seed abortion greatly reduced seed yield of many otherwise normal-looking pods.

Ancymidol Rates and Application Timing Influence Asparagus Transplant Growth

Abstract Single applications of ancymidol at 0.03, 0.12, 0.50, or 1.0 mg/plant were soil applied to asparagus seedlings (Asparagus officinalis L.) 3.5, 5.5, or 7.5 weeks after seeding. Increasing ancymidol rates from 0.03 to 1.0 mg/plant decreased bud number, fern dry weight, but not shoot number at all application times. When ancymidol was applied at 1.0 mg/plant at 3.5 weeks it reduced fleshy root production, but in plants treated at 5.5 to 7.5 weeks, it did not reduce fleshy root production. Increasing ancymidol rates from 0.03 to 1.0 mg/plant reduced the crown dry weight of plants 5.5 weeks and younger. Ancymidol from 0.03 to 1.0 mg/plant applied to 3.5-week-old plants increased the partitioning of dry matter into fern rather than crowns, but delaying application to 7.5 weeks after seeding reversed this relationship suggesting increased carbohydrate storage. Application of ancymidol from 0.03 to 1.0 mg/plant to plants 5.5-weeks-old or younger was considered detrimental to plant growth. Ancymidol at 0.50 mg/plant or less applied to 7.5-week-old plants enhanced the production of a stocky, compact transplant. Chemicals used. Ancymidol: α-cycloprophyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol.

Genotypic Variability of Soybean Response to Agrobacterium Strains Harboring the Ti or Ri Plasmids

Twenty four diverse cultivars of soybean (Glycine max [L.] Merrill) and three lines of its annual wild progenitor Glycine soja Sieb and Zucc. were tested for their response to Agrobacterium strains harboring either the Ti (tumor-inducing) plasmid (pTi) from Agrobacterium tumefaciens or the Ri (root-inducing) plasmid (pRi) from Agrobacterium rhizogenes following uniform wounding and inoculation. Based upon gall weight at 8 weeks postinfection, three G. max cultivars (Biloxi, Jupiter, and Peking) and one G. soja line, Plant Introduction (PI) 398.693B, were judged highly susceptible to A. tumefaciens strain A348 (pTiA6), ten genotypes moderately susceptible, 11 weakly susceptible, and two nonsusceptible. Of 26 genotypes inoculated with strain R1000 (pRiA4b), only seven responded in a clearly susceptible fashion by forming small, fleshy roots at internodal infection sites. Cotyledons excised from 1- or 3-day old seedlings of Peking and Biloxi cultivars also formed galls when infected in vitro with agrobacteria carrying either the Ti or Ri plasmid. Tumor lines established from cotyledon and stem galls induced by A. tumefaciens A348 (pTiA6) exhibited the T-DNA borne traits of phytohormone-independent growth and octopine synthesis. Additionally, DNA isolated from cultured tumors hybridized with labeled T-DNA probe.