共查询到20条相似文献,搜索用时 46 毫秒
1.
《Soil Science and Plant Nutrition》2013,59(2):252-257
Abstract The roots of soybean (Glycine max [L.] Merr.) establish symbiosis with nodule-inducing rhizobia and arbuscular mycorrhizal (AM) fungi. The existing nodules systemically suppress subsequent nodule formation, a phenomenon known as autoregulation. Grafting experiments revealed that some forms of autoregulation are controlled by the shoot. In the present study, we examined shoot-controlled regulation of AM fungal colonization using a reciprocal grafting technique. Ten-day-old seedlings of wild-type soybean cv. Enrei and its hypernodulating mutant En6500 were cut below the cotyledons and the shoots were grafted to self or reciprocal roots. Grafted seedlings were inoculated with Bradyrhizobium japonicum and Gigaspora rosea and grown in a glasshouse for 60 days. The arbuscule abundance of the En6500 (shoot)/En6500(root) graft was 1.5-fold higher than that of the Enrei/Enrei graft. In grafts between Enrei and En6500, an increased arbuscule abundance was detected only when En6500 was used as the shoot. The arbuscule abundance of Enrei/En6500 when Enrei was used as the shoot was comparable to that of Enrei/Enrei. The intensity of AM fungal colonization was lower in Enrei/En6500 than in the other grafting treatments. From the results obtained, we suggest that soybean shoots systemically control arbuscule formation in both AM symbiosis and nodule formation. 相似文献
2.
Kazunori Sakamoto Natsuko Ogiwara Tomomitsu Kaji 《Biology and Fertility of Soils》2013,49(8):1141-1152
Soybean plants autoregulate to suppress excessive nodulation. It has been revealed recently that the autoregulation of various legumes controls both nodulation and arbuscular mycorrhizal (AM) fungal colonization. We investigated the involvement of autoregulation in the interaction between rhizobial nodulation and AM fungal colonization. We used a wild-type soybean cv. Enrei and its hypernodulating mutant Kanto100, defective in the autoregulation. We included four different treatments: an uninoculated control, inoculation with rhizobium Bradyrhizobium japonicum alone, inoculation with AM fungus Gigaspora rosea alone, and dual inoculation with rhizobium and AM fungus. In both Enrei and Kanto100, AM fungal colonization enhanced the weight and N2 fixation of nodules, suggesting that autoregulation of host plant is not involved in the stimulatory effect of AM fungal colonization on rhizobial nodulation. In plants with the AM fungus alone, the AM fungal colonization of Enrei was comparable to that of Kanto100. In plants with dual inoculation, however, this was significantly (P?<?0.05) lower than in Kanto100. To confirm the control of AM fungal colonization by the autoregulation of host plant, a reciprocal grafting experiment was performed between Enrei and Kanto100. In plants with the AM fungus alone, AM fungal colonization was comparable among Enrei (shoot)/Enrei (root), Enrei/Kanto100, Kanto100/Enrei, and Kanto100/Kanto100 grafts. In plants with dual inoculation, however, AM fungal colonization of Enrei/Enrei and Enrei/Kanto100 grafts was significantly (P?<?0.05) lower than that of Kanto100/Enrei and Kanto100/Kanto100. These results indicate that rhizobial nodulation suppresses AM fungal colonization, and the autoregulation of host plant, initiated by nodulation, is involved in this phenomenon. 相似文献
3.
Jun-ichi Ikeda 《Soil Science and Plant Nutrition》2013,59(4):703-710
To characterize the regulation site and manner of the abundant nodulation in the soybean (Glycine max (L.) Merr.) cv. Kitamusume, three grafting eperiments were carried out as follows: reciprocal wedge grafting and inter-cultivar approach grafting between Kitamusume and a normal nodulating cultivar, Toyosuzu, as well as wedge grafting of scions of the supernodulating mutant En6500 onto either Kitamusume or Toyosuzu rootstock. In the reciprocal wedge grafting, the number of nodules per shoot dry weight and average weight per nodule in the grafted plants were consistent with those exhibited by the genotype of their rootstocks. Approach grafting did not affect the number of nodules per shoot dry weight on either side of the inter-cultivar approachgrafted plant. Although grafting of the mutant scion resulted in the loss of the autoregulatory response from the roots of both cultivars, difference in the number of nodules per g shoot dry weight still remained between the two cultivars. These results suggested that the abundant nodulation in Kitamusume is controlled by the root in a non-systemic manner and is independent of the autoregulation mechanism. 相似文献
4.
Junko Terakado Shinsuke Fujihara Shigeko Goto Ryoko Kuratani Yoshito Suzuki Shigeo Yoshida Tadakatsu Yoneyama 《Soil Science and Plant Nutrition》2005,51(3):389-395
Leguminous plants form nitrogen-fixing root nodules and the number of nodules is controlled by a self-regulating mechanism called autoregulation. However, signaling substances involved in nodule regulation have not been identified. In the present study, we used brassinolide, a most effective molecular species of plant hormone brassinosteroids, and brassinazole, an effective inhibitor of brassinosteroid biosynthesis to determine whether brassinolide played a role in systemic regulation of noduel formation in wild type soybean and its super-nodulating mutant. Foliar application or direct injection of brassinolide into the root base inhibited nodule formation and root development in the super-nodulating mutant (En6500), but not in the parent line (cv. Enrei). The internodes in the plants subjected to foliar application were significantly longer than those in the untreated plants. In contrast, the application of brassinazole on mature leaves or into the culture media resulted in the increase of the nodule number in Enrei. These treatments also inhibited internodal growth in Enrei. The results indicate that brassinosteroids may regulate the nodule number in soybean plants. The function of brassinosteroids for the systemic regulation of nodule formation was examined. 相似文献
5.
G. Morales Vela 《Soil biology & biochemistry》2007,39(3):786-792
Plant cell wall hydrolytic enzymes seem to be important to root penetration by arbuscular mycorrhiza (AM) fungi and development of AM symbiosis. In this study, taking endocellulase activity as an enzymatic model, the possibility was tested that variations in fungal colonization due to different plant capacities to form AM, can be a good experimental system to identify hydrolytic enzymes which are important to root colonization. Quantitative and qualitative endocellulase activity in roots of different symbiotic pea mutants was analysed. There were differences in root colonization among plant mutants according to their symbiotic features and a similar behaviour in fungal colonization capacities and increases in endocellulase activity in roots was also found. Mutant E107 showed the highest ethylene quantity among the phenotypes analysed, and this phytohormone could be responsible for the decrease in colonization in the mutant, but did not have any effect on cellulase activity during mycorrhiza formation. Results suggest that changes in endocellulase activity in colonized roots are associated with fungal spread within the cortex and arbuscule formation. 相似文献
6.
Root colonization by arbuscular mycorrhizal (AM) fungi has traditionally been analyzed by microscopy. However, this method is time consuming and it is often difficult to distinguish between AM and non-AM fungi. In this study, we analyzed the fatty acid profiles in soybean roots colonized by AM fungi to determine if specific fatty acids derived from AM fungi can be used as markers for the intensity of the AM fungal colonization. The wild-type Enrei and hypernodulating Kanto100 soybean cultivars were inoculated with an AM fungus (Gigaspora rosea) alone or with Bradyrhizobium diazoefficiens, which nodulates soybean roots. Fatty acids 20:1ω9, 20:4ω6, and 20:5ω3 were specifically detected in the lateral roots of AM fungus-inoculated and dual-inoculated soybean plants. In the second lateral roots, the percentage of AM-specific fatty acids (i.e., 20:1ω9, 20:4ω6, and 20:5ω3) derived from AM fungi was closely correlated with the intensity of the AM fungal colonization. We propose that the AM-specific fatty acids represent useful markers for estimating the degree of AM fungal colonization. The percentage of AM-specific fatty acids was more than twofold higher in the second lateral roots than in the first lateral roots. Thus, the degree of AM fungal colonization is probably twofold higher in the second lateral roots than in the first lateral roots. 相似文献
7.
Abstract Based on grafting studies, both supernodulating (Carroll et al. 1985a, b) and hypernodulating (Gremaud and Harper 1989) soybean ([itGlycine max} L. Merr.) phenotypes were reported to be under the control of shoot factors (Delves et al. 1986, 1987; Cho and Harper 1991). Recently Akao and Kouchi (1992) have isolated a new supernodulating mutant (En6500) from ethyl methane sulfonate (EMS)-treated Enrei, a cultivar which is widely grown in the central districts of Japan. This mutant has been shown to produce several fold as many nodules as its wild-type parent cultivar when grown at a low concentration (0.5 mol m-3) of nitrate. Moreover, it exhibited a continuous increase in the nodule number with the increasing nitrate concentration, even at 15 mol m-3 (Francisco et al. 1992), in contrast to the similar mutant nts382 in which the nodulation decreased even at the relatively low nitrate level of 5.5 mol m-3 (Carroll et al. 1985a). In this study we conducted grafting experiments to determine which plant part controls the supernodulation of En6500. 相似文献
8.
9.
Chandra Gandhi Kannan Priyadharsini Perumalsamy 《Communications in Soil Science and Plant Analysis》2017,48(5):524-538
This study examines the influence of different amounts of potassium chloride (KCl) fertilization on plant growth, nutrient accumulation and content, nutrient ratios, and root colonization by indigenous arbuscular mycorrhizal (AM) fungi in maize (Zea mays L.). KCl was applied at the rate of 0, 0.25, 0.50, 1.00, 1.50, and 1.75 mg/kg of soil. Effect of KCl on indigenous AM formation and function was evaluated in terms of the extent of root length colonization, plant growth, and nutrient uptake. Increasing concentration of KCl fertilization proportionately limited the total root length colonized by AM fungi as well as the root length with different AM fungal structures. Maize plants raised on soils amended with different concentrations of KCl were significantly taller than those raised on unamended soils. KCl application also significantly increased the total root length and root dry weight. Nevertheless, KCl fertilization did not significantly alter the root/shoot ratios. Higher concentrations of nitrogen (N), phosphorus (P), and potassium (K) were evident in shoot and root tissues of maize (except shoot N) raised on KCl-amended soils. Phosphorus concentrations in shoots and roots significantly influenced mycorrhization and root length colonized by different AM fungal structures, and such an effect was evident for root N. KCl fertilization increased the efficiency of N and P accumulation. No significant change was evident in the K:N ratios of shoots or roots, whereas the K:P ratios were significantly altered in shoots or roots in response to KCl application. 相似文献
10.
Mohsen Barin Nasser Aliasgharzad Pål Axel Olsson MirHassan Rasouli-Sadaghiani Mohammad Moghddam 《Pedobiologia》2013,56(4-6):225-232
Saline soils around Lake Urmia in northern Iran constitute a stressed environment for plants and microbial communities, including arbuscular mycorrhizal (AM) fungi. Soil and root samples were collected from fields cultivated with the glycophytes Allium cepa L. and Medicago sativa L., and sites dominated by the halophyte Salicornia europaea L. Soil and root samples were analyzed for the AM fungal signature neutral lipid fatty acid (NLFA) 16:1ω5. The roots were also examined microscopically for mycorrhizal colonization. Each plant species was sampled across a salt gradient. Microscopic examination showed no AM fungal structures in the roots of S. europaea. The highest root colonization was recorded for M. sativa. The highest NLFA 16:1ω5 values were found in soil around M. sativa roots and the lowest in soil around S. europaea roots. We found evidence for stimulation of vesicle formation at moderate salinity levels in M. sativa, which is an indication of increased carbon allocation to mycorrhiza. On the other hand, we found a negative correlation between salinity and arbuscule formation in A. cepa, which may indicate a less functional symbiosis in saline soils. 相似文献
11.
Our objective was to evaluate how increasing levels of N in the medium (0, 4, 8 and 16 mmol N added kg-1 soil) affect the interaction between Sinorhizobium and arbuscular mycorrhiza (AM) fungi in the tripartite symbiosis with Medicago sativa. Growth response, nutrient acquisition, protein content, and nitrate reductase (NR) activity were measured both in plant shoots and roots. Results showed that N levels in soil did not affect mycorrhizal colonization but they strongly influenced nodulation, particularly of mycorrhizal plants. Mycorrhizal colonization was required for a proper nodulation when no N was applied to soil. In contrast, the addition of 4 mmol N kg-1 soil reduced nodulation only in mycorrhizal plants and 8 mmol N added kg-1 soil allowed nodule formation only in non-mycorrhizal plants. Nodulation was totally inhibited in all treatments with the addition of 16 mmol N added kg-1 soil. N addition enhanced NR activity in all the treatments, while AM colonization increased the proportion of NR allocated to roots. This effect was more pronounced under the lowest N levels in the medium. The two AM fungal species showed different distribution pattern of enzymatic activities in plant tissues indicating specific physiological traits. Protein content as well as the relative proportion of protein in roots were greatly increased after mycorrhizal colonization. Glomus intraradices-colonized plants had the highest protein content in shoot and root. Mycorrhizal effects on growth, N acquisition and biochemical variables cannot be interpreted as an indirect P-mediated effect since P content was lower in mycorrhizal plants than in those which were P fertilized. Mycorrhizal colonization increased the N content in plants irrespective of the N level, but the effectiveness of AM fungi on plant N acquisition depended on the AM fungus involved, G. intraradices being the most effective, particularly at the highest N rate. N2 fixation, enhanced by AM colonization, contributed to N acquisition when a moderate N quantity was available in the soil. Nevertheless, under a high N amount the nodulating process and/or fixing capacity by Sinorhizobium was reduced in AM plants. In contrast, the AM fungal mycelium from a particular mycorrhizal fungus may continue to contribute efficiently to the N uptake from the soil even at high N levels. These results demonstrate the particular sensitivity of AM fungal species in terms of their growth and/or function to increasing N amounts in the medium. A selection of AM fungi used to address specific environmental conditions, such as N fertilization regimes comparable to those used in agronomic practices, is required for a better use of N applied to soil. 相似文献
12.
Zhen LI Songlin WU Yunjia LIU Qing YI Merinda HALL Narottam SAHA Junjian WANG Yuanfang HUANG Longbin HUANG 《土壤圈》2024,34(2):385-398
Excess available K and Fe in Fe ore tailings with organic matter amendment and water-deficiencies may restrain plant colonization and growth, which hinders the formation of eco-engineered soil from these tailings for sustainable and cost-effective mine site rehabilitation. Arbuscular mycorrhizal (AM) fungi are widely demonstrated to assist plant growth under various unfavorable environments. However, it is still unclear whether AM symbiosis in tailings amended with different types of plant biomass and under different water conditions could overcome the surplus K and Fe stress for plants in Fe ore tailings, and if so, by what mechanisms. Here, host plants (Sorghum sp. Hybrid cv. Silk), either colonized or noncolonized by the AM fungi (Glomus spp.), were cultivated in lucerne hay (LH, C:N ratio of 18)- or sugarcane mulch (SM, C:N ratio of 78)-amended Fe ore tailings under well-watered (55% water-holding capacity (WHC) of tailings) or water-deficient (30% WHC of tailings) conditions. Root mycorrhizal colonization, plant growth, and mineral elemental uptake and partitioning were examined. Results indicated that AM fungal colonization improved plant growth in tailings amended with plant biomass under water-deficient conditions. Arbuscular mycorrhizal fungal colonization enhanced plant mineral element uptake, especially P, both in the LH- and SM-amended tailings regardless of water condition. Additionally, AM symbiosis development restrained the translocation of excess elements (i.e., K and Fe) from plant roots to shoots, thereby relieving their phytotoxicity. The AM fungal roles in P uptake and excess elemental partitioning were greater in LH-amended tailings than in SM-amended tailings. Water deficiency weakened AM fungal colonization and functions in terms of mineral element uptake and partitioning. These findings highlighted the vital role AM fungi played in regulating plant growth and nutrition status in Fe ore tailings technosol, providing an important basis for involvement of AM fungi in the eco-engineered pedogenesis of Fe ore tailings. 相似文献
13.
14.
《Communications in Soil Science and Plant Analysis》2012,43(5):540-552
A series of experiments were conducted to evaluate the influence of charcoal on the development of arbuscular mycorrhiza (AM) on Leucaena leucocephala roots and the contribution of the symbiosis to the phosphorus (P) nutrition and growth of the legume. Arbuscular mycorrhizal fungal colonization of plants raised in Mansand (crushed basalt) in the first experiment was reduced if the medium was amended with fine charcoal and not with coarse charcoal. Charcoal amendment had no effect on AM fungal colonization, AM symbiotic effectiveness measured as pinnule (subleaflet) P content, or on growth of L. leucocephala in soil in the first experiment and in Mansand and in soil in subsequent experiments. However, AM fungal colonization of L. leucocephala roots, P content of pinnules, and growth of the legume were significantly enhanced (P < 0.05) by AM fungal inoculation in all experiments regardless of the growth medium used or charcoal amendment. 相似文献
15.
Easy observation methods to assess the colonization levels of arbuscular mycorrhizal (AM) fungi in plant roots are crucial for studying the biology of AM symbiosis and for considering agricultural use. Many AM studies employ Trypan Blue (TB) coupled with lactic acid to stain AM fungal structures as bright-field images; however, TB staining can be difficult to use owing to its noxiousness and high viscosity. Here, we report the development of an easy method for visualizing AM fungal structures as bright-field images using 3,3′-diaminobenzidine (DAB). Wheat germ agglutinin (WGA)-conjugated horseradish peroxidase (HRP), which specifically targets N-acetylglucosamine polymers and detects AM fungal cell walls, penetrated the cortical layers of 10% potassium hydroxide (KOH)-treated soybean roots and stained AM fungal mycelia in the presence of DAB and hydrogen peroxide (H2O2). Comparison between DAB and TB staining of soybean (Glycine max L.) roots suggested that the intactness of root systems and image contrast using DAB staining were superior. Background signals in stele observed by DAB staining were negligible as compared with those observed by WGA-fluorescein isothiocyanate staining. DAB staining, which combines the advantages of TB (easy bright-field imaging) and WGA-fluorophore (specific and high-quality) staining, provides a robust imaging method for macro- and micro-level analyses of AM roots and is applicable to at least six crops: soybean, onion (Alium cepa L.), potato (Solanum tuberosum L.), maize (Zea mays L.), rice (Oryza sativa L.), and sunflower (Helianthus annuus L.). 相似文献
16.
As common soil fungi that form symbioses with most terrestrial plants,arbuscular mycorrhizal(AM) fungi play an important role in plant adaptation to chromium(Cr) contamination.However,little information is available on the underlying mechanisms of AM symbiosis on plant Cr resistance.In this study,dandelion(Taraxacum platypecidum Diels.) was grown with and without inoculation of the AM fungus Rhizophagus irregularis and Cr uptake by extraradical mycelium(ERM) was investigated by a compartmented cultivation system using a Cr stable isotope tracer.The results indicated that AM symbiosis increased plant dry weights and P concentrations but decreased shoot Cr concentrations.Using the Cr stable isotope tracer technology,the work provided possible evidences of Cr uptake and transport by ERM,and confirmed the enhancement of root Cr stabilization by AM symbiosis.This study also indicated an enrichment of lighter Cr isotopes in shoots during Cr translocation from roots to shoots in mycorrhizal plants. 相似文献
17.
Influence of inoculation with arbuscular mycorrhizal fungi on stable isotopes of nitrogen in Phaseolus vulgaris 总被引:1,自引:0,他引:1
D. Redecker P. von Berswordt-Wallrabe D. P. Beck D. Werner 《Biology and Fertility of Soils》1997,24(3):344-346
The interactions between Phaseolus vulgaris, Rhizobium spp. strains nodulating P. vulgaris, and arbuscular mycorrhizal (AM) fungi were assessed under greenhouse conditions in a nonsterilized Typic Haplustalf soil
from Cauca, Colombia. Our results indicate a specific involvement of AM fungal species in nitrogen acquisition by the legume
plants from symbiotic nitrogen fixation and from soil. A significant specific influence of inoculation with Glomus spp. on the 15N/14N ratio in plant shoots was dependent on the inoculated rhizobial strain, but AM fungal inoculation had no significant effect
on shoot dry weight or nodule occupancy in the two different rhizobial strain treatments. The results imply that in low P
soils the effects of an improved mycorrhizal symbiosis may include improved symbiotic N2 fixation efficiency and/or improved soil N uptake.
Received: 11 May 1996 相似文献
18.
Angel I. Ortiz-Ceballos Juan J. Peña-Cabriales Carlos Fragoso George G. Brown 《Biology and Fertility of Soils》2007,44(1):181-186
Earthworms and mulch can have positive or negative effects on mycorrhizae (fungus-roots) and N uptake by plants. In the present
experiment, maize plants were grown under greenhouse conditions with or without tropical earthworms (Balanteodrilus pearsei) and mulch of velvetbean (Mucuna pruriens var. utilis). The formation of vesicles and hyphae of arbuscular-mycorrhizal (AM) fungi in roots and N uptake by maize plants was measured
at harvest. The addition of earthworms and velvetbean reduced AM root colonization. Earthworms had no effect on plant root
or shoot biomass. In the absence of velvetbean, earthworms reduced AM colonization, but when velvetbean was present, this
effect disappeared. The addition of velvetbean mulch, on the other hand, had an effect on plant biomass (above- and belowground)
and a positive effect on AM fungal colonization of roots in presence of worms, but a negative effect when worms were absent.
When both M. pruriens and B. pearsei were added, shoot and root biomass and N concentrations increased. Vesicle formation was related to velvetbean mulch decomposition
as well as the higher N concentration in maize roots. Management of mulch–earthworm interactions may be of value, particularly
in low-input and organic agricultural systems, and deserves further investigation. 相似文献
19.
Luke D. Bainard Alexander M. Koch Andrew M. Gordon John N. Klironomos 《Soil biology & biochemistry》2012
Previous research has found that conventional agricultural systems adversely affect arbuscular mycorrhizal (AM) fungi. However, there is little information on how more ecologically sustainable agricultural practices such as tree-based intercropping (TBI) influence AM fungal communities. In this study, we investigated whether TBI promotes a more abundant and diverse AM fungal community compared to conventional monocropping (CM). Abundance was estimated by measuring spore abundance and hyphal length in soil, and AM fungal colonization of corn (Zea mays) roots. Overall, AM fungal abundance was similar in both systems as corn roots from the CM and TBI systems were heavily colonized (>50%) by AM fungi throughout the growing season. Additionally, soil samples from the CM and TBI systems contained similar spore densities and hyphal length. Molecular analysis of the AM fungal community was assessed using terminal restriction fragment length polymorphism (T-RFLP) analysis of large subunit rRNA genes amplified from roots in the two cropping systems. A total of fourteen AM fungal phylotypes that belonged to the Glomeraceae were found in the two cropping systems. The TBI system had a higher AM fungal richness and contained several taxa not found in the CM system. Molecular analysis of AM fungal communities also revealed significant temporal and compositional differences between the TBI and CM systems. Within the TBI system, tree species differentially influenced the AM fungal community composition in the alley cropping regions. Future research should focus on determining whether compositional differences among AM fungal communities in CM and TBI systems have a functional effect on crop growth and productivity. 相似文献
20.
Hang Liu Fengbin Song Shengqun Liu Xiangnan Li Fulai Liu 《Archives of Agronomy and Soil Science》2019,65(2):269-279
Arbuscular mycorrhizal (AM) fungi can form symbiotic association with the roots of plants that acquire carbon (C) exclusively from the host plants and supply nitrogen (N) to the plants. In this study, our objective was to investigate the effects of the AM fungus on plant growth, C and N partitioning and accumulation of Glycine max L. grown under water stress in pot experiment. Soybean seedlings were inoculated or not inoculated with the AM fungus, and were exposed to three irrigation treatments including full irrigation, deficit irrigation and partial root-zone drying irrigation (PRD). The 15N isotope labeling was used to trace soybean N accumulation. Results showed that water stress significantly decreased plant dry weight. Compared with non-AM fungus, AM fungus increased root N and 15N concentration, and decreased stem, leaf and pod N and 15N concentrations under PRD. AM colonization decreased C and N partitioning into stem and leaf, and increased C and N partitioning into root under PRD. AM plants had greater C accumulation and N use efficiency than non-AM plants. It was concluded that AM symbiosis plays an important role in C and N dynamics of soybean grown under water stress. 相似文献