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991.
A multiple-trait breeding program for improving the symbiosis for N2 fixation betweenMedicago sativa L. andRhizobium meliloti 总被引:1,自引:1,他引:0
Summary The goal of breeding alfalfa for increased N2 fixation potential is addressed. A chronological progression of breeding, physiological, microbiological, and plant pathological research is described. Studies describing the interrelationships among plant morphological, plant physiological, andRhizobium effectiveness traits are summarized. It was concluded that N2 fixation in alfalfa is affected by coordinated responses among many physiological and biochemical traits. The simultaneous improvement of many factors in the symbiosis requires a comprehensive multiple-step breeding program. The current program includes selection in the glasshouse for seedling vigor,Rhizobium preference, shoot growth, nodule mass, root growth, nitrogenase (as measured by acetylene reduction), and nodule enzyme activity. The inclusion of additional selection traits is anticipated. Field evaluations of N2 fixation potential of alfalfa populations are made with15N isotope dilution techniques. Plant germplasm sources used in the breeding program include several heterogeneous populations which have good combining ability and pest resistance when they are intercrossed. Significant progress has been made in achieving the goal of breeding alfalfa for improved N2 fixation. 相似文献
992.
Clinton C. Shock William A. Williams Milton B. Jones D. Michael Center Donald A. Phillips 《Plant and Soil》1984,81(3):323-332
Summary The effect of S fertilization on symbiotic N2 fixation was measured with the15N technique and the N difference method in a lysimeter study using Josephine loam (Typic Haploxurults). Nitrogen fixation by subclover (Trifolium subterraneum L.) was strongly enhanced by added S. The association of soft chess (Bromus mollis L.) or filaree (Erodium botrys (Cav.) Bertol.) with subclover increased the percentage of N in subclover that was fixed, with the results that N2 fixation was increased beyond that due to the mere increase in subclover biomass.
Nitrogen fixation estimates by15N dilution and N difference methods were highly correlated (r2=0.97), and S fertilizer did not result in any significant differences in N2-fixation estimation by the two methods. Both methods were useful in distinguishing between soil N uptake and N2 fixation where S applications produced highly significant increases in both uptake and fixation.
Application of sulfur fertilizers to much annual rangeland has the potential to increase pasture productivity through enhanced
N2 fixation.
Contribution of the University of California Hopland Field Station and Department of Agronomy and Range Science, Univ. of
California, Davis, CA 95616. 相似文献
993.
Summary Homozygous mutant lines of field bean selected for (a) improved yielding potential and (b) altered plant architecture and/or physiological response were tested for symbiotic nitrogen fixing ability under field conditions in comparison with their parent cultivar.15N-tracer techniques were applied to determine %N derived from atmosphere. Data were collected on assimilate and nitrogen accumulation and distribution among various plant parts during two stages of reproductive growth.Symbiotic nitrogen fixation was closely correlated with total plant top biomass and nitrogen yield. A similar close association was found between crop yield and nitrogen harvest index. Both harvest indices tended to be negatively correlated with stage of maturity and with the amount of N derived from air per unit of area. The generally high %N derived from symbiotic N2 fixation and its comparatively small variability implies that this parameter may be difficult to improve inVicia faba under field conditions.It is concluded, that the main genetic potential for improving the amount of biological nitrogen fixation in this crop depends upon factors that promote high photosynthetic productivity and efficient N-use under appropriate agronomic conditions and with effective rhizobial associations. The establishment of rational ideotypes with a possitive impact on yield appears to be of practical significance for increasing the amount of symbiotically fixed nitrogen. 相似文献
994.
Summary Growth and N accumulation were assessed in pure and mixed plantings (2 years old) of hybrid poplar and black alder in southern Québec. Symbiotic dinitrogen fixation was evaluated by natural15N dilution. Growth of hybrid poplar plants and N accumulation in their tissues increased with their decreasing contribution to species ratio whereas no differences among treatments were measured for black alder. Yield and N content per hectare of aboveground components increased with the proportion of black alder in the plantation. Symbiotic dinitrogen fixation was estimated at 68% of alder nitrogen in both pure and mixed treatments. The maximum rate of N-fixation was 53kg ha–1 yr–1 in pure alder plots. The amount of nitrogen accumulated in entire plants of black alder from symbiotic fixation could be sufficient to balance the N export in harvested stems and branches of short-rotation plantations containing at least 33% of alder. 相似文献
995.
Hongjun Xia Xiaodan WangLi Li Shengjia WangChangchuan Guo Yao LiuLushan Yu Huidi JiangSu Zeng 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(28):2701-2706
A highly sensitive HPLC–ESI-MS method has been developed and validated for the quantification of ginkgolic acid (15:1) in a small quantity of rat plasma (50 μL) using its homologous compound ginkgolic acid (17:1) as an internal standard. GA (15:1) and GA (17:1) were extracted from biological matrix by direct protein precipitation with 5-fold volume of methanol and separated on an Elite hypersil BDS C18 column (2.1 × 100 mm, 3 μm), eluted with acetonitrile:water (92:8, v/v, containing 0.3% glacial acetic acid). Linear range was 8–1000 ng/mL with the square regression coefficient (r2) of 0.996. The lowest concentration (8 ng/mL) in the calibration curve was estimated as LLOQ with both deviation of accuracy and RSD of precision <20% (n = 6). The intra- and inter-day precision ranged from 3.6% to 9.9%, and the intra- and inter-day accuracy was between 89.9% and 101.3%. This method was successfully applied to study pharmacokinetics of GA (15:1) in rats after oral administration at a dose of 10 mg/kg. GA (15:1) pharmacokinetic parameters Cmax, Tmax, t1/2, AUC0–12h are 1552.9 ± 241.0 ng/mL, 0.9 ± 0.7 h, 5.5 ± 2.6 h, 3356.0 ± 795.3 ng h/mL, respectively. 相似文献
996.
Nathan R. West Benjamin Farnell Jill I. Murray Fraser Hof Peter H. Watson Martin J. Boulanger 《Protein science : a publication of the Protein Society》2009,18(12):2615-2623
S100A7 (psoriasin) is a calcium‐ and zinc‐binding protein implicated in breast cancer. We have shown previously that S100A7 enhances survival mechanisms in breast cells through an interaction with c‐jun activation domain binding protein 1 (Jab1), and an engineered S100A7 triple mutant (Asp56Gly, Leu78Met, and Gln88Lys—S100A73) ablates Jab1 binding. We extend these results to include defined breast cancer cell lines and demonstrate a disrupted S100A73/Jab1 phenotype is maintained. To establish the basis for the abrogated Jab1 binding, we have recombinantly produced S100A73, demonstrated that it retains the ability to form an exceptionally thermostable dimer, and solved the three dimensional crystal structure to 1.6 Å. Despite being positioned at the dimer interface, the Leu78Met mutation is easily accommodated and contributes to a methionine‐rich pocket formed by Met12, Met15, and Met34. In addition to altering the surface charge, the Gln88Lys mutation results in a nearby rotameric shift in Tyr85, leading to a substantially reorganized surface cavity and may influence zinc binding. The final mutation of Asp56 to Gly results in the largest structural perturbation shortening helix IV by one full turn. It is noteworthy that position 56 lies in one of two divergent clusters between S100A7 and the functionally distinct yet highly homologous S100A15. The structure of S100A73 provides a unique perspective from which to characterize the S100A7‐Jab1 interaction and better understand the distinct functions between S100A7, and it is closely related paralog S100A15. 相似文献
997.
Glendining M.J. Poulton P.R. Powlson D.S. Macdonald A.J. Jenkinson D.S. 《Plant and Soil》2001,233(2):231-239
In an earlier paper we presented data from an experiment in which nitrogen-15-labelled fertilizer was applied in spring to barley on the Rothamsted long-term Spring Barley Experiment, at rates of 48, 96 or 144 kg N ha–1. A substantial proportion (between 28 and 39%) of this 15N remained in the soil (0–70 cm) and stubble at harvest, mostly in organic form. The present paper follows the fate of this `residual' 15N over the following 2 years. Small amounts of `residual' 15N were recovered in the following two spring barley crops; 8% in the first and 3% in the second. The overall loss of `residual' 15N (i.e. `residual' 15N not recovered in crops and soil to a depth of 70 cm) over the 2 years was 23%. This is equivalent to just 8% of the total 15N originally applied. There was surprisingly little difference in the behaviour of the `residual' 15N in soils containing very different quantities of soil organic matter. 相似文献
998.
Ferdinand Bohlamnn Autar K. Dhart Jasmin Jakupovic Robert M. King Harold Robinson 《Phytochemistry》1981,20(6):1425-1426
A new caryophyllene derivative, 15-acetoxy-5,6-dihydro-6,7-dehydrocaryophyllen-5-one, has been isolated from the roots of Fleischmannia pycnocephaloides. Other Fleischmannia sp. yielded previously known compounds. 相似文献
999.
Chunshuai Wu Guofeng Bao Guanhua Xu Yuyu Sun Lingling Wang Jiajia Chen Jinlong Zhang Chu Chen Qiancheng Zhu Zhiming Cui 《Journal of cellular biochemistry》2019,120(4):5355-5366
Traumatic spinal cord injury is a common and severe complication after an accident. As we all know that neurite outgrowth of neurons is difficult after a spinal cord injury. Endosome system is associated with cargoes transportation and contributes in promoting the neuronal capability for neurite outgrowth. EH domain-containing protein 1 (EHD1) transports proteins through the endosome system, especially in the recycling endosomes and regulating the neurite outgrowth. In mammalian cells, the involvement of the ubiquitin-proteasome system in endosomal sorting has been well established. Two RING fingers and a DRIL (double RING finger-linked) 1 (Triad1) plays an important role in membrane trafficking and its mutant results in the wrong accumulation of receptors in endosomes and plasma membrane. In this current study, we reasonably integrated the results of the above research and investigated the regulating function of Triad1 to EHD1 following the spinal cord injury. We characterized the upregulated expression and distribution of Triad1 and EHD1 in the neurons after SCI and declared the interaction between Triad1 with EHD1 both in vitro and in vivo. Triad1 regulated the interaction between itself and the full-length or EH domain of EHD1, which influenced the neurite outgrowth of PC12 cells. Our data delineate a novel interaction between Triad1 and EHD1 that may contribute to the regulation of neurite outgrowth for neurons after the spinal cord injury. 相似文献
1000.