Co-incorporation of biodegradable wastes with crop residues to reduce nitrate pollution of groundwater and decrease waste disposal to landfill     

C. R. Rahn    G. D. Bending    R. D. Lillywhite  & M. K. Turner 《Soil Use and Management》2009,25(2):113-123

Return of high nitrogen (N) content crop residues to soil, particularly in autumn, can result in environmental pollution resulting from gaseous and leaching losses of N. The EU Landfill Directive will require significant reductions in the amounts of biodegradable materials going to landfill. A field experiment was set up to examine the potential of using biodegradable waste materials to manipulate losses of N from high N crop residues in the soil. Leafy residues of sugar beet were co‐incorporated into soil with materials of varying C:N ratios, including molasses, compactor waste, paper waste, green waste compost and cereal straw. The amendment materials were each incorporated to provide approximately 3.7 t C per hectare. The most effective material for reducing nitrous oxide (N₂O) production and leaching loss of NO₃^? was compactor waste, which is the final product from the recycling of cardboard. Adding molasses increased N₂O and NO₃^? leaching losses. Six months following incorporation of residues, the double rate application of compactor waste decreased soil mineral N by 36 kg N per hectare, and the molasses increased soil mineral N by 47 kg N per hectare. Compactor waste reduced spring barley grain yield by 73% in the first of years following incorporation, with smaller losses at the second harvest. At the first harvest, molasses and paper waste increased yields of spring barley by 20 and 10% compared with sugar beet residues alone, and the enhanced yield persisted to the second harvest. The amounts of soil mineral N in the spring and subsequent yields of a first cereal crop were significantly correlated to the lignin and cellulose contents of the amendment materials. Yield was reduced by 0.3–0.4 t/ha for every 100 mg/g increase in cellulose or lignin content. In a second year, cereal yield was still reduced and related to the cellulose content of the amendment materials but with one quarter of the effect. Additional fertilizer applied to this second crop did not relieve this effect. Although amendment materials were promising as tools to reduce N losses, further work is needed to reduce the negative effects on subsequent crops which was not removed by applying 60 kg/ha of fertilizer N.  相似文献   

Mechanical transmission of maize rayado fino marafivirus (MRFV) to maize and barley by means of the vascular puncture technique     

K. Madriz-Ordeñana  R. Rojas-Montero  T. Lundsgaard  P. Ramírez  H. Thordal-Christensen  & D.B. Collinge 《Plant pathology》2000,49(2):302-307

Maize rayado fino marafivirus (MRFV) was mechanically transmitted to kernels of three Costa Rican maize cultivars by the vascular puncture technique. A transmission rate of up to 43.2% was obtained for cultivar HC-57. The rate of MRFV transmission to maize was possibly affected by the morphology of the kernel, which may influence physical access to the vascular tissue after water imbibition. Transmission to maize was confirmed by western blot and immunosorbent electron microscopy. By slight modifications of the procedure, MRFV was also transmitted to barley. This is the first report of MRFV infecting a species outside the supertribe Andropogonodae. Virus infection and replication in barley were confirmed by RT-PCR detection of MRFV RNA and by detection of the virus by ELISA.  相似文献   

Metabolic differentiation of bloodstream forms of Trypanosoma brucei brucei into procyclic forms. Effect of hydroxyurea, arabinosyl adenine, and serum omission   总被引：1，自引：0，他引：1  

A Markos  A Blah?sková  M Kalous  E Bysková  K Byska  E Nohynková 《Folia parasitologica》1989,36(3):225-238

Bloodforms of Trypanosoma brucei brucei STIB 247 taken from rats and containing more than 80 per cent short stumpy forms, differentiated in vitro to procyclic forms in medium SDM 79 (Brun and Sch?nenberger 1979), enriched with 3 mmol.dm-3 cis-aconitate. Cell division was abolished by the addition of hydroxyurea (200 micrograms.ml-1) or arabinosyl adenine (20 micrograms.ml-1 to the cultivation medium, or by the omission of serum from the medium. The ultrastructure of exponentially growing controls was rearranged within 24 h. The endogenous respiration and the respiration stimulated by proline, succinate, and 2-oxoglutarate were detectable within 12 h; after 48 h the respiration rates were comparable to those found in the established procyclic forms. After 12 h the respiration was inhibited by 200 mumol.dm-3 KCN, and by 20 mumol.dm-3 antimycin to the extent found in procyclic forms. Hydroxyurea did not significantly affect respiration. Activities of procyclic-stage enzyme markers malate dehydrogenase, threonine dehydrogenase, succinate: cytochrome c reductase, and NADH: cytochrome c reductase rose within 48 h of differentiation to values which were close to those found in established procyclic forms. The activity of glutamate dehydrogenase (NAD-specific), however, was only 1/3 of that in the procyclics, and no citrate synthase was detected in differentiating culture. Glycosomal malate dehydrogenase was detected after 6 h. In the presence of hydroxyurea or arabinosyl adenine, or in the absence of serum, respiration rates, marker enzyme activities, and glycosomal malate dehydrogenase developed to the extent comparable to the untreated controls. The results suggest that it is possible to separate the process of differentiation from cell proliferation. Cell division is not a necessary prerequisite of differentiation.  相似文献   

Isolation and characterization of a potyvirus associated with bushy dwarf symptom in chickpea, Cicer arietinum, in India     

V. ANJAIAH  D. V. R. REDDY  S. K. MANOHAR  R. A. NAIDU  Y. L. NENE  A. S. RATNA 《Plant pathology》1989,38(4):520-526

A potyvirus that induced stunting and a characteristic bushy appearance at the apical region, due to proliferation of terminal branches with narrowed, reduced and deformed leaflets, was isolated from chickpea in India. The virus was sap-transmissible to 14 species of Chenopodiaceae, Leguminosae, Solanaceae and Malvaceae; Chenopodium amaranticolor was a good local lesion host. Virus particles, trapped by immunosorbent electron microscopy and stained with uranyl acetate, were 710 ×10 nm long. Purified virus preparations contained a single polypeptide species of 32,500 Da and one nucleic acid species of 3.1 · 10⁶ Da. The virus was serologically related to soybean mosaic, azuki bean mosaic and peanut mottle viruses but not to clover yellow vein, pea seed-borne mosaic and bean yellow mosaic viruses.
On the basis of these properties, the virus was identified as a previously undescribed potyvirus in chickpea, for which the name chickpea bushy dwarf virus is proposed.  相似文献   

The haustorial host-parasite interface in rust-infected bean leaves after high-pressure freezing     

G. M. Knauf  K. Welter  M. Müller  K. Mendgen   《Physiological and Molecular Plant Pathology》1989,34(6)

The haustorial fine structure of the bean rust fungus, Uromyces appendiculatus var. appendiculatus, was studied within the cells of its host, Phaseolus vulgaris. Results were obtained after high-pressure freezing and subsequent freeze-substitution or freeze-fracturing. Good preservation of leaf tissue after freeze-substitution needed cryoprotection with 8% methanol. For freeze-fracturing, no chemical treatment was applied. In addition to the organelles which are generally found in fungi after cryo-fixation, tubular-vesicular complexes were found in the cytoplasm. Both techniques revealed an extrahaustorial matrix of even width, surrounding the haustorial body. The extrahaustorial membrane was not undulated, and the side facing the plant cytoplasm was lined with a delicate fringe of well-stained material. The extrahaustorial membrane was nearly devoid of intramembrane particles. The host plasma membrane in infected tissue, especially the protoplasmic face, had fewer intramembrane particles than those in uninfected tissue. The haustorial plasma membrane contained many intramembrane particles.  相似文献   

Morphological Basis of Resistance in Cotton to the WhiteflyBemisia Tabaci     

N. S. Butter  B. K. Vir 《Phytoparasitica》1989,17(4):251-261

The morphological basis of resistance to the whiteflyBemisia tabaci Genn. (Aleyrodidae: Hemiptera) was studied. The plant characters examined were leaf area, thickness of leaf lamina, hair density, hair length, angle of insertion of leaf hair, and density of gossypol glands. Hair density and leaf thickness were positively correlated with the population ofB. tabaci, and a positive correlation was obtained between the adult whitefly population and gossypol glands on stem internodes. Cotton genotype USA-22 (sparsely hairy) was found to be more tolerant toB. tabaci than was genotype USA-13 (velvety hairy). The use of thinner and glabrous leaved cotton varieties is suggested to minimize the whitefly menace in cotton.  相似文献   

Effects of temperature,relative humidity and age of conidia on the incidence of spotting on gerbera flowers caused by Botrytis cinerea     

J. Salinas  D. C. M. Glandorf  F. D. Picavet  K. Verhoeff 《European journal of plant pathology / European Foundation for Plant Pathology》1989,95(1):51-64

In recent years, spotting of ray florets of gerbera flowers has become an important problem. This type of small necrotic lesions may occur before, but especially shortly after harvesting the flowers.Botrytis cinerea was easily isolated from such lesions. Inoculation withB. cinerea only gave typical necrotic lesions, when dry conidia were dusted on the flowers with a short period of high rh after inoculation. At 18–25 °C a high rh for at least 5 hours was necessary. Rotting of ray florets and receptacles byB. cinerea occurred when inoculated flowers were kept wet for a few days. Spots consist of one to several necrotic, usually epidermal cells. A single conidium could give rise to a necrotic lesion after germination. Germination of conidia and lesion formation occurred between 4 and 25 °C; at 30 °C, germination and lesion formation did not occur. Between 18 and 25 °C, many lesions became visible within 1 day after inoculation; at 4 °C it took 2 to 3 days before lesions could be seen. If kept dry, conidia ofB. cinerea remained ungerminated on ray florets of gerbera flowers and could be removed from the ray florets. Within 1 day at high rh, germination occurred and lesions were produced. Conidia ofB. cinerea, stored dry, were able to survive much longer than the lifetime of a gerbera flower. Even after storage at room temperature for up to 14 months, some conidia were able to germinate in vitro and on ray florets and induce the formation of lesions. Addition of gerbera pollen diffusate stimulated germination and lesion formation.  相似文献   

Investigations concerning soil-borne viruses in sugarbeet in Sweden1     

K. LINDSTEN 《EPPO Bulletin》1989,19(3):531-537

Some experiments with soil-borne beet viruses in cement tubes in a wire netting enclosure are described. It is confirmed that rhizomania (virus + vector) originating from German soil can survive and cause rhizomania in Sweden. Antisera produced in 1987 to one German BNYVV isolate and to one Swedish soil-borne beet virus isolate, 86-109, which is distinct from BNYVV, were used to check ELISA reactions in the tube beets. Positive ELISA was obtained not only for BNYVV but also for the 86-109 virus from tubes with German inoculum. Beets from tubes with Swedish inoculum reacted only against 86-109 antiserum. In 1988-09, ELISA of 118 sugarbeet plants from Öland and 73 from Skåne, collected in 42 different fields with spots resembling rhizomania, showed no or weak reactions against 86-109 antiserum, in contrast to plants collected in 1987. However, after transplanting the field plants into a warm glasshouse and using bait plants it was shown in ELISA and in transmission to Chenopodium quinoa that many of the bait plants became infected with the 86-109 and ‘related viruses’ but not with BNYVV. Viruses of the 86-109 type seem to be common both in Sweden and elsewhere but may escape detection, especially in mixed infections with BNYVV.  相似文献   

Biological control by Trichoderma harzianum of damping-off of lettuce caused by Rhizoctonia solani1     

M. WILSON  E. K. CRAWFORD  R. CAMPBELL 《EPPO Bulletin》1988,18(1):83-89

Ten isolates of Trichoderma harzianum were tested for their ability to control lettuce seedling damping-off caused by introduced Rhizoctonia solani. T. harzianum isolates TRC 9 and 28 both reduced damping-off. Dual culture experiments were used to select isolates for the study of antibiotic production and mycoparasitism. T. harzianum isolate TRC 12 produced volatile and non-volatile antibiotics, whilst TRC 33 produced only non-volatile antibiotics. T. harzianum isolates 018-2/Y and TRC 9,15 and 28 mycoparasitized R. solani by coiling around and lysing the host hyphae. It appeared that mycoparasitism was more important than antibiosis in the biological control of damping-off.  相似文献   

Chemotherapy of experimental toxoplasmosis with special reference to robenidine     

S K Bakhtari  J Jíra 《Folia parasitologica》1988,35(3):193-198

Robenidine as an anticoccidial agent alone (in doses of 50 and 100 mg/kg) or in association with two other antiprotozoal compounds--pyrimethamine and sulfadoxine (in doses of 2.5 and 250 mg/kg, respectively) were tested in the treatment of chronically infected mice with an avirulent cyst-forming HF strain of Toxoplasma gondii. The efficacy of the used drugs was evaluated by the cysts number in the brains of treated mice versus control group, antibody level and viability of survived cysts by the consecutive infection of mice. According to these criteria none of the tested drugs alone or combined exhibited to be able to produce an effective cure of cyst-stage of toxoplasmosis in experimental mice.  相似文献