Oak powdery mildew changes growth patterns in its host tree: host tolerance response and potential manipulation of host physiology by the parasite     

Marie-Laure Desprez-Loustau  Gilles Saint-Jean  Benoît Barrès  Cécile Françoise Dantec  Cyril Dutech 《Annals of Forest Science》2014,71(5):563-573

Context

Parasites can induce strong effects on their host’s growth, not only as a result of host resource exploitation (growth loss) but also with a potential adaptive value for host (tolerance response) and themselves (increased transmission).

Aims

We assessed these three types of phenotypic changes in oak seedlings infected by powdery mildew.

Methods

A manipulative field experiment with three levels of parasite inoculum was designed in order to tease apart infection from genetic effects on oak growth. Seedlings were monitored during 3 years for height growth, phenology and infection.

Results

Powdery mildew infection induced both significant growth loss and qualitative changes in plant architecture. The most striking and unexpected change was increased growth polycyclism in infected seedlings. This benefitted both the host as a form of compensation for infection-caused height loss, and the pathogen, by increasing sporulation.

Conclusion

The study highlights the effect of parasites in the expression of plant phenotypic traits, such as phenology and ultimately tree architecture. Both host tolerance and parasitic manipulation may be involved in the observed changes in growth patterns. These results suggest a complex interplay between development and defence in trees and emphasize the need to better assess tolerance mechanisms when considering the defence strategies of trees against pathogens.  相似文献   

长期施磷黑土中磷的吸附–解吸特征及其影响因素     

王琼  陈延华  张乃于  秦贞涵  金玉文  朱平  彭畅  Colinet Gilles  张淑香 《植物营养与肥料学报》2022,28(9):1569-1581

  【目的】  比较长期不施磷与施磷黑土对外源磷的吸附–解吸特征,为黑土区磷素管理提供理论基础。  【方法】  供试黑土长期定位试验位于吉林省公主岭市,始于1990年。2018年选择其中不施肥(CK),施氮钾肥(NK),施氮磷钾肥(NPK)和氮磷钾+有机肥(NPK+M) 4个处理小区,采集0—20、20—40和40—60 cm土层的土壤样品,分析了土壤理化性质,采用恒温平衡法测定了土壤磷的吸附–解吸特征,并由此计算得到磷最大吸附量(Q_m)、吸附亲和力常数(K_Q)、最大缓冲容量(MBC)、磷吸附饱和度(DPS)、最大解吸量(D_m)和解吸率(D_r)。  【结果】  随着平衡溶液中磷浓度的增加,磷的吸附量与解吸量均呈先快速增加后逐渐趋于平衡的过程。与不施磷处理(CK和NK)土壤相比,施磷处理(NPK、NPK+M)减少了磷的吸附量,增加了磷的解吸量。与不施磷处理相比,施磷处理在0—60 cm剖面上的Q_m和MBC值分别降低了4.94%～63.46%和15.90%～75.18%,D_r值增加了8.52%～474.0%,以NPK+M处理变化量最大。施磷处理比不施磷处理在0—60 cm土壤剖面上全磷和有机质含量分别增加了34.40%～145.5%和12.77%～50.07%,游离态铁铝氧化物(Fe_d+Al_d)含量降低了5.14%～11.35%。冗余分析表明,不施磷处理土壤的有机质、Fe_d+Al_d和全磷,以及施磷处理中的Fe_d+Al_d、络合态铁铝氧化物(Fe_p+Al_p)、pH和有机质是影响磷吸附解吸特征参数的主要土壤因子,分别解释了不施磷和施磷处理全部变异的77.59%和90.62%。土壤有效磷(Olsen-P)与磷吸附饱和度(DPS)相关关系表明,所研究的黑土DPS环境界限值为8%左右,NPK+M处理中3个土层的DPS_M-P值(由Mehlich-3 浸提的磷、铁和铝计算)为7.77%～25.96%,DPS_O-P值(由Olsen-P和Q_m计算)为17.24%～24.75%,均高于此环境界限值,具有磷素流失的风险。  【结论】  长期施磷降低了黑土对外源磷的吸附量,增加了磷解吸量。长期不施磷肥,土壤对磷的吸附和解吸主要受有机质、游离态铁铝氧化物的影响。而长期施肥,特别是有机肥与化肥配合处理,土壤中游离态和络合态铁铝氧化物、有机质及pH是影响磷吸附解吸特征的主要因素。  相似文献   

Nitrogen isotopic composition of leached nitrate and soil organic matter as an indicator of denitrification in a sloping drained agricultural plot and adjacent uncultivated riparian buffer strips   总被引：1，自引：0，他引：1  

Claire Billy  Gilles Billen  François Birgand 《Soil biology & biochemistry》2010,42(1):108-117

In the small, agricultural, artificially drained Orgeval watershed δ¹⁵N values of leached nitrates and soil organic nitrogen were found to be significantly higher than the primary nitrogen (N) sources from which they are derived, namely, synthetic fertilizers, atmospheric deposition, and symbiotic or nonsymbiotic N₂ fixation (all with δ¹⁵N close to zero). In vertical soil profiles, the δ¹⁵N of organic N increased with depth, reaching higher values (up to 8‰) particularly at stations that were frequently waterlogged as judged from ochre iron traces, such as downhill field sites or in riparian buffer strips. Nitrification, volatilization, and denitrification are the main fractionating processes able to modify the isotopic composition of soil N. Using a newly designed algorithm for calculating the equilibrium isotopic composition of all soil N species, resulting from the average annual balance of their transformations, we show that the observed trends can be explained by the action of denitrification. We suggest that the isotopic composition of soil organic N can be used as a semiquantitative indicator of the intensity of denitrification integrated over century-long periods.  相似文献   

Hemagglutinating activity associated with bovine herpesvirus type 1   总被引：1，自引：0，他引：1  

Pierre Trpanier  Cecile Sguin  Yolande Bastien  Gaston Boulay  Gilles Lussier  Michel Trudel 《Veterinary microbiology》1985,10(6):517-523

Using C57BL/HPB mouse erythrocytes, hemagglutination has been observed with the Los Angeles and Colorado-1 strains of bovine herpesvirus type 1 and with 12 other Canadian field isolates as well. The specificity of the hemagglutination observed with the viral strains has been confirmed by a hemagglutination-inhibition assay.  相似文献   

Further evaluation of exotic germplasm of perennial ryegrass for use in French plant breeding programmes     

Gilles Charmet  François Balfourier 《Euphytica》1991,57(1):67-76

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Factorial regression analysis of genotype by environment interaction in ryegrass populations, using both isozyme and climatic data as covariates     

François Balfourier  Jose Alberto Oliveira  Gilles Charmet  Enrique Arbones 《Euphytica》1997,98(1-2):37-46

A sample of 58 natural ryegrass populations (Lolium perenne L.) from the French and Spanish oceanic coast was evaluated for three seasonal growth traits (i.e. spring, autumn and winter vigour traits) in 5 evaluation sites (three in France and two in Spain). This sample showed a high level of genotype (population) × environment (evaluation sites) interactions for the three agronomic traits. A factor regression analysis, using both isozyme frequencies of populations and climatic factors of evaluation sites as covariates, was carried out on a sub-sample of 30 populations in order to explain these interactions. This method succeeded in explaining most population × location interactions by the product of two covariates. For instance, for spring vigour trait, 72.8% of the interaction term could be explained by the use of two covariates: the PGI2-20 allelic frequency of populations and the minimum temperature of the coldest month of evaluation sites. This study shows the advantage of such a method for plant breeders who need to identify promising ryegrass populations for their breeding objectives. A number of genetic and evolutionary hypotheses are also discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Method for determining nitrogenous heterocycle compounds in wine     

Keim H  de Revel G  Marchand S  Bertrand A 《Journal of agricultural and food chemistry》2002,50(21):5803-5807

Qualitative and quantitative analyses of N-heterocycle compounds were conducted by using a liquid-liquid extraction followed by additional chemical silica gel purification and injection into a gas chromatographic (GC) column coupled to a nitrogen-phosphorus detector (NPD). The purified extract fraction was investigated by GC-NPD and by GC-mass spectrometry. The compounds identified and quantified in wines were 2,4,5-trimethyloxazole, 2,4-dimethylthiazole, and 4-methylthiazole by GC-NPD and both 2-acetylthiazole and 2-acetyl-2-thiazoline by GC-MS. The procedure was used to analyze different wines and gave reliable and reproducible results.  相似文献   

Possible mechanism for involvement of cysteine in aroma production in wine     

Marchand S  de Revel G  Vercauteren J  Bertrand A 《Journal of agricultural and food chemistry》2002,50(21):6160-6164

Under conditions close to those of wine, that is, low pH, aqueous medium, and low temperatures, this work describes N-(2-sulfanylethyl)-2-oxopropanamide (1), a new intermediate in the formation of 2-acetylthiazole from methylglyoxal and cysteine. 1 was characterized by MS, derivatization MS, and (1)H and (13)C NMR and was synthesized from 2-sulfanylethanamine and ethyl pyruvate. A formation pathway for 2-acetylthiazole from methylglyoxal and cysteine is proposed, in which 1 is a new intermediate in Maillard-type reactions in systems under mild conditions.  相似文献   

Effects of freeze-thaw stress during soil storage on microbial communities and methidathion degradation     

Manuel Pesaro  Franco Widmer  Gilles NicollierJosef Zeyer 《Soil biology & biochemistry》2003,35(8):1049-1061

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Acrylamide formation from asparagine under low moisture Maillard reaction conditions. 2. Crystalline vs amorphous model systems     

Robert F  Vuataz G  Pollien P  Saucy F  Alonso MI  Bauwens I  Blank I 《Journal of agricultural and food chemistry》2005,53(11):4628-4632

The formation of acrylamide was investigated in model systems based on asparagine and glucose under low moisture Maillard reaction conditions as a function of reaction temperature, time, physical state, water activity, and glass transition temperature. Equimolar amorphous glucose/asparagine systems with different water activities were prepared by freeze drying and were shown to quickly move to the rubbery state already at room temperature and a water activity of above 0.15. The acrylamide amounts were correlated with physical changes occurring during the reaction. Pyrolysis and kinetics of acrylamide release in amorphous and crystalline glucose/asparagine models indicated the importance of the physical state in acrylamide formation. In amorphous systems, acrylamide was generated in higher concentrations and at lower temperatures as compared to the crystalline samples. Time and temperature are covariant parameters in both systems affecting the acrylamide formation by thermal processes. On the other side, the water activity and glass transition temperature do not seem to be critical parameters for acrylamide formation in the systems studied.  相似文献