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11.
《Communications in Soil Science and Plant Analysis》2012,43(15):2032-2045
This study was carried out to investigate the levels of copper (Cu) contamination in coffee fields in Kilimanjaro and Arusha regions, Tanzania, to increase the database on the contamination of soils by Cu-based fungicides in coffee fields. Surface (0–20 cm deep) soil samples were collected from different farms in Kilimanjaro and Arusha regions. Coffee, banana, and bean plant samples were collected from the locations of soil sampling. Soil and plant samples were analyzed at the Department of Soil Science, Sokoine University of Agriculture, Morogoro, Tanzania. It was found that the calcium chloride (CaCl2)–extractable Cu was less than the detection limit of flame atomic absorption spectrometry. Diethylenetriaminepentaacetic acid (DTPA)–extractable (24 to 366 mg Cu kg?1 soil) and aqua regia–extractable (80 to 806 mg Cu kg?1 soil) Cu levels were high enough to raise environmental alarm (based on European Union guidelines) in the Cu fungicide–treated soils as compared with natural Cu levels in untreated soils (1 to 12 mg Cu kg?1 soil for DTPA and 22 to 32 mg Cu kg?1 soil for aqua regia–extractable Cu). Coffee, banana, and bean plants grown on soils contaminated by Cu fungicides had varied concentrations of Cu that were greater than the concentrations of Cu in the plants collected from the uncontaminated soils. Stepwise regression analysis carried out to investigate the relationships between the soil properties and the concentrations of Cu in plants revealed a significant (P = 0.01) positive relationship (R2 = 0.4) between organic carbon and the concentration of Cu in banana leaves. Aqua regia–extractable Cu was positively correlated (P = 0.03, R2 = 0.4) with the concentrations of Cu in banana leaves. For bean leaves, electrical conductivity (EC) had a positive significant (P = 0.01) relationship (R2 = 0.56) with the concentrations of Cu in the plants. It is recommended that further research be carried out to investigate the dynamics and bioavailability of Cu for the different crops interplanted in the coffee fields. 相似文献
12.
咖啡锈菌生理小种的研究进展及我国咖啡锈菌生理小种变化的动态预测 总被引:1,自引:0,他引:1
综述了世界咖啡锈菌生理小种的研究进展,并对我国咖啡锈菌生理小种变化的动态进行预测 相似文献
13.
E. J. Tondoh 《Biology and Fertility of Soils》1998,26(4):336-340
Hyperiodrilus africanus (Beddard) is a 12-cm to 16-cm-long earthworm, which is widely distributed in West and Central Africa. It lives in the upper
10–20 cm of the soil, and feeds on a mixture of soil and above-ground litter. Cocoons obtained in the laboratory hatched on
average 17 days after deposition and produced two juveniles on average. Paired individuals fed soil amended with 2% coffee
residues grew significantly (P<0.05) faster than those in the control soil. Daily individual weight increments were respectively 6.1 mg worm–1 day–1 and 1.0 mg worm–1 day–1 in supplemented and control soil. The generation time was short, and cocoon production reached 9.6 month–1 (i.e. 115 cocoons adult–1 year–1). When H. africanus collected from the field were raised in the laboratory, they grew slowly, laid fewer cocoons and mortality was high. Demographic
parameters indicated an improvement when H. africanus were raised in batches rather than individually. Mating enhanced cocoon production although parthenogenesis was possible.
Received: 4 April 1997 相似文献
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A. Loureiro M.R. NicoleV. Várzea P. MoncadaB. Bertrand M.C. Silva 《Physiological and Molecular Plant Pathology》2012,77(1):23-32
Histological and ultrastructural studies were undertaken to compare Colletotrichum kahawae growth and the sequence of responses it induced in resistant and susceptible coffee genotypes. Coffee resistance was characterized by a restricted fungal growth associated with hypersensitive-like cell death and early accumulation of phenolic compounds, such as flavonoids (cytoplasmic contents) and hydroxycinnamic acid derivatives (cell walls). This accumulation of phenols in the cell walls preceded their lignification and thickening. In the susceptible genotype, a late accumulation of hydroxycinnamic acid derivatives in a number of cell walls and the encasement of some intracellular hyphae were also observed, but these delayed host responses did not prevent fungal growth and sporulation. 相似文献
19.
A. B. Eskes M. Toma-Braghini 《European journal of plant pathology / European Foundation for Plant Pathology》1982,88(6):219-230
The influence of leaf age on incomplete resistance to race II of coffee leaf rust (Hemileia vastatrix), which is the most common race in Brazil, was tested in the greenhouse and in the field. Three stages of leaf age were distinguished: young leaves which had just fully expanded and still had a shiny appearance on the day of inoculation, adult leaves of 1 to 4 months old, and old leaves of 6 to 12 months old which were formed in the foregoing growing season.The effect of leaf age varied with the coffee genotype. With the susceptibleCoffea arabica cvs Mundo Novo and Catuai no important effect of leaf age on latency period and reaction type was observed. Lesion density, depending on inoculation method, was affected to some extent, older leaves showing lower values. With genotypes of theC. canephora cv. Kouillou, which varied in level of incomplete resistance, adult leaves appeared to be more resistant than young and old leaves. This adult leaf resistance was expressed mainly by a lower lesion density, but also by a longer latency period and a lower reaction type.Within the hybrid populations Icatu and Catimor, genotypes with race-specific incomplete resistance were tested and others of unknown specificity. Resistance was expressed mainly by a low reaction type. Generally, resistance decreased with increasing leaf age, which was occasionally associated with a complete change in reaction type. Contrary to cv. Kouillou, in Icatu and Catimor no higher susceptibility of young leaves than of adult leaves was observed.The incomplete resistance to race I of the differential CIFC H152/3, heterozygous for SH4, was also better expressed in young leaves, older ones becoming gradually more susceptible.It is concluded that for screening incomplete resistance to coffee leaf rust leaves of different ages should be tested.Samenvatting Het effect van bladleeftijd op incomplete resistentie van koffie tegen fysio II van koffieroest (Hemileia vastatrix), het algemeen voorkomende fysio in Brazilië, werd getoetst in de kas en in het veld. Drie stadia in de bladleeftijd werden onderscheiden: jong blad dat net volgroeid was en nog glansde op de dag van inoculatie, volwassen blad van 1 tot 4 maanden oud en oud blad van 6 tot 12 maanden oud dat gevormd was in het voorafgaande groeiseizoen.Het effect van bladleeftijd varieërde met het koffiegenotype. Bij de vatbareCoffea arabica rassen Mundo Novo en Catuai werd geen belangrijke invloed waargenomen van bladleeftijd op latentieperiode en reactietype. Lesiedichtheid werd, afhankelijk van de inoculatiemethode, wel enigszins beïnvloed. Bij vijf genotypen van hetC. canephora ras Kouillou, die varieerden in niveau van incomplete resistentie, bleek volwassen blad veelal resistenter dan jong en oud blad. Deze resistentie uitte zich voornamelijk door een lagere lesiedichtheid maar ook door een langere latente periode en een lager reactietype.Van de hybride populaties Icatu en Catimor werden enkele genotypen met fysiospecifieke incomplete resistentie getoets alsmede genotypen waarvan de specificiteit van de resistentie onbekend was. Verschillen in resistentie uitten zich voornamelijk door verschillen in reactietype. Over het algemeen nam de resistentie af bij toenemende bladouderdom. Anders dan bij de cv. Kouillou werd bij Icatu en Catimor geen grotere vatbaarheid van jong ten opzichte van volwassen blad waargenomen. Bij sommige genotypen kwam resistantie zelfs alleen maar tot uiting in het jonge blad, terwijl het volwassen blad normaal vatbaar was. Een soortgelijk effect van bladleeftijd werd waargenomen bij inoculatie van de koffiedifferentieel CIFC H153/3, die heterozygoot is voor het resistentiegen SH4, met het incompatibele fysio I.Er wordt geconcludeerd dat voor het bepalen van incomplete resistentie tegen koffieroest bladeren van verschillende ouderdom getoetst dienen te worden. 相似文献
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为提高咖啡园砖红壤肥料有效性,采用土壤好气培养法进行试验,以尿素和硫酸铵为氮肥,研究了砖红壤区不同咖啡园土壤硝化作用特征。结果表明,土壤性质、氮肥种类和环境温度显著影响砖红壤硝化速率。在3种因素共同作用下,硝化速率呈“S”型变化曲线;土壤性质中土壤pH是影响咖啡园砖红壤硝化特性的主要因素,pH值越高的土壤硝化速率越快(酸性土壤),21 d后土壤硝化率达到100%;不同氮肥的硝化过程有明显差异,施尿素的土壤硝化速率显著高于施硫酸铵的土壤(p<0.05);温度会影响硝化速率,30 ℃土壤硝化速率显著大于25 ℃土壤。因此,针对不同土壤特性和环境温度,应选择不同种类氮肥,以提高肥料利用率。 相似文献