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PubMed2001

A comparison of the success of root resected molars and molar position implants in function in a private practice: results of up to 15-plus years.

BACKGROUND: When faced with a furcated molar, today's clinician must decide between a number of treatment options, including root resection, tooth removal, and implant placement. This paper assesses the results in one private clinical practice of root resection and subsequent restoration or molar implant placement and subsequent restoration. Clinical considerations in treatment selection are discussed. METHODS: A retrospective analysis of treated patients was carried out by examining active and inactive patient charts. When patients had discontinued therapy, every effort was made to determine the reason for leaving the private practice, so as to assess the impact of previously undocumented treatment failure on the statistics in question. RESULTS: A total 701 root resected molars and 1,472 molar implants were evaluated after > or = 15 and 13 years in function, respectively. Resection of the distal root of a mandibular molar demonstrated the lowest success rate (75%). All other success rates for various root resected molars in function ranged from 95.2% to 100%. Lone standing implants in second molar positions demonstrated the lowest success rate (85%). All other implant use in molar positions demonstrated a success rate ranging from 97.0% to 98.6%. Root resected molars and molar implants demonstrated the highest degree of failure when they were lone standing terminal abutments. Seven out of 23 (30.4%) root resected molar failures, and 17 of 45 (37.8%) of the molar implant failures were associated with untreated parafunction. Cumulative success rates were 96.8% for root resected molars and 97.0% for molar implants. Success and failure are discussed by tooth and/or implant position, and resected root, where applicable. Possible ramifications of these findings upon treatment planning are also reviewed. CONCLUSIONS: Both molar root resection and appropriate restoration and molar implant placement and restoration demonstrated a high degree of success in function. However, this success rate is markedly affected when either the root resected molar or molar implant is a lone standing terminal abutment. Care must be taken to choose the appropriate treatment modality for a given patient scenario.

Adult↗
PubMed2004

The interface between retained roots and dental implants: a histologic study in baboons.

BACKGROUND: This study is a derivative of another study evaluating implant efficacy in baboons. In the previous study it was noted that some implants were placed near or into retained root tips. The purpose of this study was to evaluate the effect of the inadvertent placement of root form implants into or near retained root fragments. METHODS: The baboon has severe dilacerations at the apices of the roots, making extraction very difficult; 120 teeth were extracted from 10 baboons. After the sites had healed, root form implants were placed in each of the sites. Sites were either loaded at various time intervals or left unloaded. Block sections were removed and processed for histologic examination. RESULTS: When the specimens were analyzed, it was noted that several implants were placed through retained root fragments, while others were placed through the periodontal ligament of other root fragments. In a few cases, implants were close to, but not in contact with, either the root or the periodontal ligament. These implants functioned as well as the others in the study. Histologically, there was no inflammation at any site. In some sections, the roots were in intimate contact with the implants, while in others, there was a gap between the two. Where the implant was in contact with the periodontal ligament, there was no apparent fibrous encapsulization of the implant. In some areas, it appeared that a calcified material was deposited on the implants. It was not possible to determine whether this material was bone or cementum. CONCLUSION: Unintentional placement of dental implants into retained root fragments did not result in any inflammation and may have produced cementum or cementum-like matrix on the titanium surface adjacent to the periodontal ligament of the retained root tip.

Animals↗
PubMed1997

Lack of specificity in electrophysiological identification of lower sacral roots during selective dorsal rhizotomy.

The authors investigated the efficacy of anal sphincter electromyography (EMG) in identifying the lower sacral roots during selective dorsal rhizotomy. In nine children undergoing selective dorsal rhizotomy for cerebral palsy (CP) spasticity, direct electrical stimulation of the L1-S5 dorsal and ventral roots was performed while monitoring EMG responses from the anal sphincter and lower-extremity muscles. Anal sphincter activation was seen with stimulation of lumbosacral roots at many levels. Stimulation of dorsal and ventral roots gave anal sphincter EMG responses in 100% of the dorsal and ventral roots from L-4 and caudally. Only at the L-1 level did a minority of nerve roots have anal sphincter response to stimulation. Patterns of extremity muscle and sphincter activation specific to the S3-5 roots, namely anal sphincter activation without activation of other muscle groups, were found in only five (22%) of 23 roots stimulated. The pattern of stimulation responses in the majority of S3-5 roots indicated that the pathophysiology of lower-extremity spasticity in CP may involve the anal sphincter and does not spare the lower sacral roots. Thus, this study indicates that electrophysiological mapping alone, without anatomical identification, cannot be used to identify the lower sacral roots during selective dorsal rhizotomy for CP spasticity, and it proposes a model for investigation of associated bowel and bladder symptoms.

Anal Canal↗
PubMed2000

Hydrolytic enzymes and ability of arbuscular mycorrhizal fungi to colonize roots.

The production of hydrolytic enzymes from external mycelia associated with roots and colonized soybean roots (Glycine max L.) inoculated with different arbuscular-mycorrhizal (AM) fungi of the genus GLOMUS:, and the possible relationship between these activities and the capacity of the AM fungi to colonize plant roots was studied. There were differences in root colonization and plant growth between the GLOMUS: strains, and also between two isolates of G. mosseae. Hydrolytic activities in the root and external mycelia associated with roots differed in the AM fungi tested. Correlations were only found between the endoxyloglucanase activity of the external mycelia associated with roots of the AM fungi tested and the percentage root colonization or plant growth. However, hydrolytic activities of roots colonized by the different endophytes correlated with those of external mycelia. The hydrolytic activities were not qualitatively different because the endoxyloglucanase from AM colonized roots and the external mycelia did not show a high degree of polymorphism in the different species of fungus tested. The possible role of the hydrolytic activity of external hyphae of AM fungi was discussed as a factor affecting fungal ability to colonize the root and influence plant growth.

Enzymes↗
PubMed1990

Gravity-induced changes in intracellular potentials in elongating cortical cells of mung bean roots.

Gravity-induced changes in intracellular potentials in primary roots of 2-day-old mung bean (Vigna mungo L. cv. black matpe) seedlings were investigated using glass microelectrodes held by 3-dimensional hydraulic micro-drives. The electrodes were inserted into outer cortical cells within the elongation zone. Intracellular potentials, angle of root orientation with respect to gravity, and position within the root of the impaled cortical cell were measured simultaneously. Gravistimulation caused intracellular potential changes in cortical cells of the elongation zone. When the roots were oriented vertically, the intracellular potentials of the outer cortical cells (2 mm behind the root apex) were approximately - 115 mV. When the roots were placed horizontally cortical cells on the upper side hyperpolarized to - 154 mV within 30 s while cortical cells on the lower side depolarized to about - 62 mV. This electrical asymmetry did not occur in cells of the maturation zone. Because attempts to insert the electrode into cells of the root cap were unsuccessful, these cells were not measured. The hyperpolarization of cortical cells on the upper side was greatly reduced upon application of N,N'-dicyclohexylcarbodiimide (DCCD), an inhibitor of respiratory energy coupling. When stimulated roots were returned to the vertical, the degree of hyperpolarization of cortical cells on the previous upper side decreased within 30 s and approached that of cortical cells in non-stimulated roots. This cycle of hyperpolarization/loss of hyperpolarization was repeatable at least ten times by alternately turning the root from the vertical to the horizontal and back again. The very short (<30 s) lag period of these electrical changes indicates that they may result from stimulus-perception and transduction within the elongation zone rather than from transmission of a signal from the root cap.

Cell Differentiation↗
PubMed1998

Molecular genetics of root gravitropism and waving in Arabidopsis thaliana.

When Arabidopsis thaliana seedlings grow embedded in an agar-based medium, their roots grow vertically downward. This reflects their ability to sense the gravity vector and to position their tip parallel to it (gravitropism). We have isolated a number of mutations affecting root gravitropism in Arabidopsis thaliana. One of these mutations, named arg1, affects root and hypocotyl gravitropism without promoting defects in starch content or in the ability of seedlings' organs to respond to plant hormones. The ARG1 gene was cloned and shown to code for a protein with a J domain at its amino terminus and a second sequence motif found in several cytoskeleton binding proteins. Mutations in the AGR1 locus promote a strong defect in root gravitropism. Some alleles also confer an increased root resistance to exogenous ethylene and an increased sensitivity to auxin. AGR1 was cloned and found to encode a putative transmembrane protein which might be involved in polar auxin transport, or in regulating the differential growth response to gravistimulation. When Arabidopsis seedlings grow on the surface of agar-based media tilted backward, their roots wave. That wavy pattern of root growth derives from a combined response to gravity, touch and other surface-derived stimuli. It is accompanied by a reversible rotation of the root tip about its axis. A number of mutations affect the presence or the shape of root waves on tilted agar-based surfaces. One of them, wvc1, promotes the formation of compressed root waves under these conditions. The physiological and molecular analyses of this mutant suggest that a tryptophan-derived molecule other than IAA might be an important regulator of the curvature responsible for root waving.

Arabidopsis↗
PubMed2001

Environmental regulation of lateral root initiation in Arabidopsis.

Plant morphology is dramatically influenced by environmental signals. The growth and development of the root system is an excellent example of this developmental plasticity. Both the number and placement of lateral roots are highly responsive to nutritional cues. This indicates that there must be a signal transduction pathway that interprets complex environmental conditions and makes the "decision" to form a lateral root at a particular time and place. Lateral roots originate from differentiated cells in adult tissues. These cells must reenter the cell cycle, proliferate, and redifferentiate to produce all of the cell types that make up a new organ. Almost nothing is known about how lateral root initiation is regulated or coordinated with growth conditions. Here, we report a novel growth assay that allows this regulatory mechanism to be dissected in Arabidopsis. When Arabidopsis seedlings are grown on nutrient media with a high sucrose to nitrogen ratio, lateral root initiation is dramatically repressed. Auxin localization appears to be a key factor in this nutrient-mediated repression of lateral root initiation. We have isolated a mutant, lateral root initiation 1 (lin1), that overcomes the repressive conditions. This mutant produces a highly branched root system on media with high sucrose to nitrogen ratios. The lin1 phenotype is specific to these growth conditions, suggesting that the lin1 gene is involved in coordinating lateral root initiation with nutritional cues. Therefore, these studies provide novel insights into the mechanisms that regulate the earliest steps in lateral root initiation and that coordinate plant development with the environment.

Anthocyanins↗
PubMedDate not supplied

Supernumerary roots.

Supernumerary roots are one of the development anomalies pertaining to the tooth root morphology. It is generally well known that the deciduous and permanent anterior teeth have a single root. Maxillary molars have three roots and mandibular molars have two roots. Pertaining to the premolars, except for the maxillary first premolars all other premolars have a single roots. These supernumerary roots may be due to the disturbances of the Hertwig's epithelial root sheath forming the root. Cases have been reported where in both the deciduous and permanent dentition exhibiting supernumerary roots. Here with we are presenting cases of supernumerary roots in permanent teeth involving maxillary third molars, mandibular first, second molars and mandibular second premolars.

Adolescent↗
PubMed2003

Lumbar root compression in the lateral recess: MR imaging, conventional myelography, and CT myelography comparison with surgical confirmation.

BACKGROUND AND PURPOSE: Previous authors have shown that conventional myelography is superior to plain CT in the assessment of root compression in the lateral recess, but this question has never been evaluated with respect to MR imaging of the lumbar level. Our purpose was to assess the accuracy of MR imaging, conventional myelography, and postmyelography CT (CT myelography) of the lumbar level in identifying degenerative lateral recess root compression with surgical confirmation. METHODS: MR imaging, conventional myelography, and CT myelography of the lumbar level were assessed in the imaging of 58 lateral recesses at 38 lumbar levels in 26 patients who underwent surgery for radiculopathy with degenerative lateral recess abnormality. Each lateral recess was graded as normal, small without root compression, small with root compression, or severe root compression. RESULTS: MR imaging underestimated root compression in 28% to 29% of the cases in which root impingement was surgically confirmed. Conventional myelography underestimated root compression in only 5% to 7% of the cases and correctly predicted impingement in 93% to 95%. CT myelography underestimated root compression in 38% of the surgically confirmed cases. CONCLUSION: MR imaging significantly underestimated root compression caused by degenerative changes in the lateral recess. Although MR imaging is a superb study when used in the search for degenerative disk disease and disk protrusion, conventional myelography is a crucial supplemental study that is necessary to confirm degenerative root impingement in the lateral recess as the cause of radiculopathy.

Adult↗
PubMed1992

The effectiveness of the air-powder abrasive device for root planing during periodontal surgery.

The efficacy of the air-powder abrasive device (APAD) in root planing during flap surgery was assessed in vitro and in vivo. Two teeth on which full-thickness flaps were raised underwent root planing by hand-scaling alone and hand-scaling combined with APAD. One tooth extracted prior to surgery underwent unrestricted hand-scaling under a binocular microscope (control). The two teeth root planed in situ and the tooth root planed in vitro were observed by scanning electron microscopy (SEM). Then, 10 patients with periodontitis requiring flap surgery were selected for a clinical study. After raising full-thickness flaps, 29 sites from five patients underwent root planing using hand-scaling combined with APAD, whereas 22 sites from six patients underwent root planing by hand scalers only. SEM revealed that root surfaces planed in situ by hand-scaling combined with APAD were smoother than those root-planed using hand scalers alone. The control tooth surface was as smooth as those submitted to combined root planing. The clinical study showed that sites submitted to combined root planing displayed enhanced attachment level gain and pocket reduction. These results, associated with the shortened instrumentation time, suggest APAD as a useful instrument for root planing during flap surgery.

Air↗
PubMed2003

[Study on the combination principles about aconite roots by electrospray ionization mass spectrometry].

AIM: To explore the combination principle about aconite roots from the chemical point of view. METHODS: Analyzing and comparing the nordeterpenoid alkaloids in the crude aconite roots, the decoction of crude aconite roots and aconite roots with some other Chinese traditional herbs by electrospray ionization trap tandem mass spectrometry. Detecting the pH value of the decoction of crude aconite roots and of some other Chinese traditional herbs; studying the influence of acidity to the hydrolysis of standard sample of mesaconitine. RESULTS: Most of diester-diterpenoid alkaloids in the decoction of aconite roots and the decoction of aconite roots with liquorice roots are hydrolyzed, and the hydrolysis of alkaloids are inhibited in the decoction of aconite roots with Pinellia tuber or Schisandra. The acidity of the decoction of aconite roots or liquorice is lower than the decoction of Pinellia tuber or Schisandra; standard sample of mesaconitine can not be hydrolyzed in acid water. CONCLUSION: Acidity is a key factor to influence the hydrolysis of diester-diterpenoid alkaloids, and the hydrolysis of alkaloids are inhibited in high acidity, which lead to the high toxicity of the decoction containing aconite roots.

Aconitine↗
PubMed2003

[Temporal and spatial distribution characteristics of the crop root in intercropping system].

The ecological mechanism of competition and compensation between the crop root systems of two different intercropping patterns, wheat-soybean and corn-cabbage, was studied by field experiment. The results showed that the annual growth peak of wheat-soybean roots in intercropping was interlacing, the growth of root weight and length expressed synchronism, and the peak of root weight was appeared earlier than that of root length. The vertical distribution of the two crops' root system in two intercroppings was reduced gradually along with soil depths, which also showed that the multiple growth waves moved progressively. The root system distributed horizontally in intercropping system also showed a clearly unbalanced distribution. The root system distribution of out-row for corn elongated 20.4-40.8 cm to cabbage rows, but that of cabbage elongated only 8.5-12.6 cm to corn. The cross extent of root systems in corn-cabbage intercropping was decreased from 40.2 cm to 20.1 cm by fertilization, and the place of cross point for root concentrated region was changed from 20.5 cm to 12.4 cm below soil surface by fertilizer supply. The place of cross point for root concentrated region was an important index to decide the degrees of competition.

Brassica↗
PubMed2004

[Seasonal variations in biomass and salidroside content in roots of Rhodiola sachalinensis as affected by gauze and red film shading].

Rhodiola sachalinensis A. Bor, a perennial herb, belonging to the family Crassulaceae, is mainly distributed in mountains at the altitudes of 1,700-2,500 m. It is a typical alpine plant and a very important medicinal plant with high activities of anti-fatigue, anti-senescence, and anti-radiation, due to the secondary metabolite salidroside in its root. Our previous findings have proven that red light promotes salidroside synthesis remarkably but decreases biomass insignificantly, resulting in a higher yield of salidroside in roots of Rh. sachalinensis in a greenhouse. In order to investigate the influences of shading and red light on seasonal variations in biomass and salidroside content in Rh. sachalinensis roots, the effects on 3 or 4 years old Rh. sachalinensis plants in a nursery in Daxinganling Mountain (124 degrees 02' E, 50 degrees 30' N) were studied in 2001. Compared to the control (CK) of full sunlight, 6 treatments with neutral transparent film and gauze, or red film alone had been conducted for 131 days. In treatment I, Rh. sachalinensis was shaded with neutral transparent film and gauze to achieve an irradiance 51.8% of full sunlight. In treatment II, the plants were shaded by red film alone, but the irradiance was as that in treatment I. In treatments III, IV, V and VI, neutral transparent film and gauze were originally used on May 8, then shifted to red film on Jun 3, July 4, August 4 and September 2, respectively and all experiments stopped on September 16, 2001. Rh. sachalinensis roots were harvested on 2-4th from June to September and finally on September 16, and root-biomass and salidroside content were measured. Root-biomass in plants decreased significantly under shading with neutral transparent film and gauze compared to the control with full sunlight, but little variations in salidroside content and yield. In comparison with shading by neutral transparent film and gauze, root-biomass reduced lightly and salidroside content and yield in roots were increased remarkably under red-film shading. At the end of the season, salidroside content under red light was 163% in 3-year-old and 155% in 4-year-old Rh. sachalinensis roots; whereas salidroside yields were 144% in 3-year-old and 145% in 4-year-old Rh. sachalinensis roots to those in plants under shading. The results also showed that the enhancement in the salidroside content and yield were little related to the duration of red film shading, which implied that in order to increase salidroside content and get higher salidroside yield, but less affect root-biomass, Rh. sachalinensis may be shaded with red film just several days before harvest.

Biomass↗
PubMed2005

[Self-regulation of xylem pressure in barley roots under salt stress].

Xylem pressure in young barley roots, measured in vivo with a xylem pressure probe, showed constant, irregular fluctuations both under altered or unchanged environmental conditions. When mild salt stress was applied or when the stress was eliminated, xylem pressure in barley roots exhibited intense self-regulation or relaxation, leading to a consequence that the difference of xylem pressure before and after the salt stress was greatly narrowed and the barley plants could maintain a relatively stable xylem pressure. The process of regulation or relaxation of xylem pressure in barley roots lasted about one hour or more before a relatively stable state was achieved. The self-regulation or relaxation of xylem pressure was not dependent on the initial status of the xylem pressure. Both the fluctuation and the self-regulation of xylem pressure in plant roots could exert substantial uncertainties on the conventional measurements of water potential and the radial reflection coefficient of barley roots, especially when the pressure bomb (Schollander bomb) or root pressure probe was used, because the pressure was in constant change and the measurements of some data points could not reflect the true situation within plants. The radial reflection coefficients of barley roots, when subjected to NaCl stress, were in a range from 0.56 to 0.97 if the maximum responses of the plants to stress were taken. However, if the pressure responses after the self-regulation were adopted, the coefficients fell in between 0.24 and 0.32 for the same plants. Such results could have two implications. On the one hand, care had to be taken when the radial reflection coefficients of roots were determined, because the points where the data were taken could greatly alter the final results. In this case, it could be necessary to specify the type of the results, i.e. the maximum response or the regulation-diverted response of plants to stress and hence the resultant radial reflection coefficients of roots. Also, care must be taken when the data were used in the interpretation of the physiological processes in terms of plant response to salt stress. On the other hand, the self-regulation or relaxation of xylem pressure in barley roots, which prevented great variations in xylem pressure in plants, could be beneficial to plants under salt stress and could as well be related to the mechanisms of salt resistance in plants. Large self-regulation or relaxation of xylem pressure under different environmental conditions was not an universal phenomenon in plants because it was not seen in wheat roots before and after the application of salt stress.

Hordeum↗
PubMed2003

Maxillary incisor root forms in orthodontic patients in Nairobi, Kenya.

OBJECTIVE: To evaluate, radiographically, the root forms of maxillary incisors in a sample of patients seeking orthodontic treatment in Nairobi, Kenya. DESIGN: A retrospective study of maxillary incisor root forms based on periapical radiographs. SETTING: A private dental clinic in Nairobi, Kenya. MATERIALS AND METHODS: The study comprised 393 maxillary incisors in 100 consecutive subjects (51 boys, 49 girls) aged 9-24 years. Intra-oral periapical radiographs of the incisors were evaluated. An index was used to categorise the roots as follows: 0=normal, 1=short, 2=blunt, 3=apical bend, 4=pipette apex. RESULTS: Normal root form was recorded in 60%, short in 12.5%, blunt in 7%, apical bend in 13%, and pippete-apex in 7% of the roots. Sixty nine percent of the pippete-apex roots were in central incisors and 94% of the roots with apical bend were in lateral incisors. Seventy three percent of short roots were in females. CONCLUSION: Based on evidence from previous studies on risk of root resorption which indicates that pipette and blunt roots are the forms mostly involved in this phenomenon, the present data imply that about 14% of the roots may have been at risk of moderate to severe resorption during fixed orthodontic treatment.

Adolescent↗
PubMed2005

[Effects of sucrose and light on the growth and production of secondary metabolites in Pueraria phaseoloides hairy roots].

Effects of sucrose concentrations and light on the growth and production of total isoflavones and puerarin in Pueraria phaseoloides hairy roots cultured onto solid MS media supplemented with 1%, 3%, 5%, 7% and 9% sucrose, respectively, were investigated. The results showed that among the sucrose concentrations tested, 3% sucrose in the medium enhanced the growth and stimulated accumulation of total isoflavones and puerarin in P. phaseoloides hairy roots, After cultured for 20 days, the biomass of hairy roots reached 0.48 g (DW dry weight)/flask and its contents of total isoflavones and puerarin were 25.44 mg/g (DW) and 11.64 mg/g (DW), respectively. In comparison with 3% sucrose, the dry weight proliferation of hairy roots cultured with 5% sucrose was increased by 7.0%, while cultured with 1%, 7% and 9% sucrose, the dry weight proliferation of hairy roots was decreased by 62.4%, 42.8% and 65.3%, their total isoflavones content was decreased by 57.4%, 13% and 33.4% and their puerarin content was decreased by 47.9%, 15.8% and 35.1%; but their content of total soluble sugars was increased 0.52, 1.45 and 1.54 times, respectively. Compared with hairy roots in blue light and white light, the biomass of hairy roots cultured in the dark for 30 days was 0.83 g (DW)/flask and was increased by 37.1% and 23.3%, respectively. The content of total isoflavones in hairy roots cultured in white light was as much as 1.15 times and 1.19 times that in blue light and in the dark, respectively. It was also observed that hairy roots cultured in blue light and white light partly became light green and that blue light could inhibit accumulation of puerarin in hairy roots and the puerarin content in hairy root cultured in white light and in the dark were 1.61 times and 1.52 times that in blue light, respectively.

Culture Media↗
PubMedDate not supplied

Clinical evaluation of 3 overdenture concepts with tooth roots and implants: 2-year results.

PURPOSE: In the present cohort study, overdentures with a combined root and implant support were evaluated and compared with either exclusively root- or implant-supported overdentures. Results of a 2-year follow-up period are reported, namely survival of implants, root copings, and prostheses, plus prosthetic complications, maintenance service, and patient satisfaction. MATERIALS AND METHODS: Fourteen patients were selected for the combined overdenture therapy and were compared with 2 patient groups in which either roots or implants provided overdenture support. Altogether, 14, 17, and 15 patients (in groups 1, 2, and 3, respectively) were matched with regard to age, sex, treatment time, and observation period. The mean age was around 67 years. Periodontal parameters were recorded, radiographs were taken, and all complications and failures were registered during the entire observation time. The patients answered a 9-item questionnaire by means of a visual analogue scale (VAS). RESULTS: One implant failed and 1 tooth root was removed following longitudinal root fracture. Periodontal/peri-implant parameters gave evidence of good oral hygiene for roots and implants, and slight crestal bone resorption was measured for both. Technical complications and service performed were significantly higher in the first year (P < .04) in all 3 groups and significantly higher in the tooth root group (P < .03). The results of the VAS indicated significantly lower scores for satisfaction, speaking ability, wearing comfort, and denture stability with combined or exclusive root support (P < .05 and .02, respectively). Initial costs of overdentures with combined or root support were 10% lower than for implant overdentures. CONCLUSION: The concept of combined root and implant support can be integrated into treatment planning and overdenture design for patients with a highly reduced dentition.

Aged↗
PubMed2006

[Induction of cucumber hairy roots and effect of cytokinin 6-BA on its growth and morphology].

Hairy roots of Cucumis sativus L. could be incited directly from the cut edges of 10-day-old cotyledon explants after infection with the strain Agrobacterium rhizogenes ATCC15834 harboring agropine-type plasmid, pRiA4b for 5 days. It was observed that the percentage of rooting cotyledon explants was more than 90 % 10 days after infection. Hairy roots could grow rapidly and highly branched on solid plant growth regulator-free MS medium. The PCR amplification of rol B genes and vir C gene showed that T-DNA of Ri plasmid of A. rhizogenes was integrated and expressed into the genome of transformed cucumber hairy roots. A bacterium-free transformed cucumber hairy root line was selected to culture on solid MS medium to examine influence of exogenous cytokinin 6-BA on growth and morphology alteration of cucumber hairy roots. The results showed that cytokinin 6-BA can influence the growth and altered the morphology of hairy roots. With increasing of 6-BA concentrations, Cucumber hairy roots become shorter and thicker and less branched. 6-BA at the concentration of 0.1 to approximately 3.0 mg/L could delay the appearance of maximum growth peak by 5 days and decreased the content of soluble protein, enhanced the activities of SOD and POD and decreased the levels of endogenous ethylene evolution in cucumber hairy roots. Our results also indicated that cytokinin 6-BA in the medium could influence growth and morphology alternation of cucumber hairy roots and delay its senescence of hairy roots by acting through ethylene.

Cucumis sativus↗