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1.
Summary Potato tubers were inoculated with two biotypes ofPhytophthora infestans then stored at 3,7, 10 and 15°C. Image analysis quantified average reflective intensity (ARI) of diseased tissue from cut
surfaces of sample tubers. Tuber tissue infection and infection rate were measured by calculating Mean ARI of samples. Average
tuber tissue infection and infection rate was minimal at 3°C (P.i.-US8 orP.i.-US1). Tuber tissue infection increased at temperatures >3°C, from 220 Mean ARI seven days after inoculation (dai) to 190–150
Mean ARI 50 dai (depending on cultivar and biotype ofP. infestans). Rate of tuber tissue infection caused byP.i.-US1 at 7°C was about zero in cv. Snowden but greater than −0.2 ARI day−1 (cvs Russet Burbank and Superior). Rate of late blight infection in tuber tissue generally increased with temperature from
−0.2 ARI day−1 (at 7°C) in all cultivars to a maximum of −0.8 ARI day−1 (10°C). 相似文献
2.
Summary Leaf stomatal resistance varies considerably in response to changes in environmental conditions. Understanding cultivar differences
in the response of stomata to these conditions is important for effectively simulating water-use and growth.
In this study the stomatal resistance of three field grown potato (Solanum tuberosum L.) cultivars Atlantic. Monona and Norchip was observed in response to photosynthetic photon flux density, leaf to air vapour
pressure difference and root zone available soil water. Substantial variation in stomatal resistance was accounted for by
functions of the environmental variables for both Monona and Norchip. The explained variation for Atlantic was considerably
less. Light saturation occurred near 500 μmol m−2 s−1. Increasing stomatal resistance above 1000 μmol m−2s−1 was also observed but is likely an artifact of stomatal closure on days in which mid-day leaf water potentials dropped below
critical levels. Although the leaf presumably insufficient to obtain substantial effects. The soil water status was partially
linked to the average 1000 h to 1500 h stomatal resistance on clear, sunny days. Significant differences were observed among
the cultivars in the response of stomata to changes in the available soil water. 相似文献
3.
Wide variation (>10.28 times) of fish yield (Cyprinus carpio Linnaeus, 1758) was obtained in a trial arranged in concrete cisterns (100 l) receiving compost (T-2), Diammonium phosphate
(=DAP) (T-3) and vermicompost (T-4) as direct application fertilizer and manure in those systems. Significant (P < 0.005) differences were observed in diversity and abundance of plankton in response to manure application among treatments.
Highest phyto- and zooplankton population was found in the cistern treated with vermicompost followed by DAP, compost and
control. In all the treatments dry weight and population of both phyto- and zooplankton population were significantly (P < 0.005) higher than control. The highest production of fish was obtained in the cisterns treated with vermicompost (3,970.56 kg ha−1 90 day−1), followed by diammonium phosphate (3,080.45 kg ha−1 90 day−1), compost (1,952.64 kg ha−1 90 day−1) and the lowest in the control (385.92 kg ha−1 90 day−1). Vermicompost might be cost-effective manure in carp culture, replacing the expensive chemical fertilizer diammonium phosphate. 相似文献
4.
Summary Excessive fertilizer application in North Carolina, USA results in high residual soil levels of P, K and total soluble salts
in potato fields. Our objectives were to determine the salt sensitivity of three common cultivars (Atlantic. Snowden and Superior),
and the effects of planting density and fertilization on stand establishment, soilborne disease, and yield. Greenhouse results
suggest that potato growth and emergence, but not shoot initation, are reduced by high salinity. On a Portsmouth fine sandy
loam, high fertilizer rates did not reduce stands of cv. Atlantic in the field in 1996 or 1997. Excess N resulted in moreRhizoctonia stem canker in 1996, and lower yields at the lower planting density in 1997. Yield compensation for reduced plant density
occurred in 1997 at the lower N rates (56 and 112 kg N ha−1) and at the high PK rate (49 kg P and 139 kg K ha−1). 相似文献
5.
Summary Soil in a potato field naturally infested with black dot (Colletotrichum coccodes) was fumigated with methyl bromide at 126 g m−2 or left unfumigated. Potato seed tubers (cv. BP1) uninfected, lightly infected (1–25% surface affected), severely infected
(26–100% surface affected) and severely infected withC. coccodes but dusted with prochloraz manganese chloride as Octave 2.5% DP at 750 g per 100 kg seed were planted in fumigated and unfumigated
soil. When harvested, the incidence of black dot on the progeny of infected seed planted in unfumigated soil was twice that
of progeny in fumigated soil, with progeny of uninfected seed having a 68.5 times higher disease incidence in unfumigated
soil. Black dot on progeny tubers was reduced by pre-treatment of seed with prochloraz in fumigated soil only. With black
dot infested fields, planting disease-free seed or treating seed with fungicides would not decrease disease on progeny tubers. 相似文献
6.
Gülay Tuncer 《Potato Research》2002,45(2-4):153-161
Summary Powdery scab, caused by the fungusSpongospora subterranea, has developed in the Cappodocia region of Turkey because of changes in agronomic practices, such as excessive irrigation
and nitrogen fertilizer use and growth of highly susceptible cultivars. The most suitable irrigation and nitrogen application
levels were established to maintain powdery scab at minimum levels without affecting potato yield. Three irrigation levels
were used in 1998 (673, 897, 1121 mm) and five in 1999 (329, 494, 658, 823, 987 mm). Nitrogen levels were applied 150, 300,
450, 600 kg N ha−1. In 1998, least powdery scab occurred with 673 mm irrigation, which yielded 41 t ha−1 potatoes. The lowest disease severity occurred in 1999 with 494 mm irrigation and 150 kg N ha−1. At these levels, tuber yield was 34 t ha−1 which was not significantly different from the highest yield measured. In 1999 and at two of the three irrigation levels
inl998, nitrogen increased disease severity. 相似文献
7.
8.
Monsuang Yangthong Nongporn Hutadilok-Towatana Wutiporn Phromkunthong 《Plant foods for human nutrition (Dordrecht, Netherlands)》2009,64(3):218-223
The aqueous extracts of four marine algae, Caulerpa racemosa var. macrophysa, Gracilaria tenuistipitata var. tenuistipitata, Sargassum sp., and Ulva lactuca, from the coastal areas in Southern Thailand, were prepared by boiling dried seaweed powder in water for 3 h, and by autoclaving
each sample at 120 °C for 3 h. They were then freeze-dried and evaluated for their antioxidant activities using DPPH (1, 1-diphenyl-2-picrylhydrazyl),
hydroxyl radical (OH•) and superoxide anion (O2•−) scavenging assays. Boiling extracts of the seaweeds, except C. racemosa, were found to have higher total phenolic contents (TPC) than those obtained from the autoclave method. The antioxidant results
also showed that O2•− scavenging activity existed only in the boiling extracts of C. racemosa, G. tenuistipitata, and U. lactuca. In DPPH and OH• assays, however, almost all the boiling extracts were less active than the autoclave ones. Among the four alga species, Sargassum sp. was the most active. Both extracts of this seaweed had the highest TPC and also displayed the strongest DPPH• and OH• inhibitory activities. A strong positive-correlation between the antioxidant potency and TPC of the autoclave extracts was
found, while for the boiling extracts such relation was very weak. This result thus reflected that in addition to the phenolic
compounds, there might be some other active components present in these extracts involved in the antioxidant activity. 相似文献
9.
Experiments were conducted to evaluate the effects of light, seed burial depth, and flooding on germination, emergence and growth of Ludwigia hyssopifolia. Germination was strongly stimulated by light, suggesting that seeds of this species are positively photoblastic. Seeds sown on the soil surface gave the greatest percentage of seedling emergence in plastic trays, and no seedlings emerged from seeds buried in soil at depths of ≥1 cm. Intermittent or shallow flooding suppressed emergence and growth of L. hyssopifolia. Flooding to a depth of 2 cm for 4 days out of 7 days reduced seedling emergence by more than 71% and seedling dry matter by 97% compared to where the soil had not been flooded. Flooding up to a depth of 10 cm however, when delayed to 21 days after sowing, did not significantly suppress growth of this species. This study illustrates the role of seed burial by tillage and flooding as two important tools for the management of L. hyssopifolia. 相似文献
10.
Summary Preplant soil solarisation and mouldboard ploughing to a depth of 30 and 60 cm respectively were evaluated in two field experiments
for the control ofColletotrichum coccodes causing black dot of potato. Solarisation reduced disease incidence by 45% when tarping was done for eight weeks and temperatures
reached 56°C in the top 5 cm of soil. With a six week tarping period and lower maximum temperature (50°C) the reduction in
disease was a nori-significant 25%. Mouldboard ploughing to a depth of 30 cm reduced black dot by 34% and was twice as effective
as ploughing to a depth of 60 cm. 相似文献
11.
The miscibility and crystallization behavior of the blends of poly(vinylidene fluoride) (PVDF) and ethylene/vinyl acetate(20/80)
copolymer (EVAc80) have been studied using a differential scanning calorimeter and a polarizing microscope equipped with a
heating stage. From the melting point depression, the values of interaction energy densityB were calculated to be −1.3004 (cal/cm3) and the Flory-Huggins interaction parameterχ
12 was found to be −0.0818 at 445.6 K. With increasing concentration of EVAc80, the radial growth rate of spherulite was reduced
drastically. The FT-IR analysis of samples quenched from the melt to various temperatures showed increasing content ofβ-phase with increasing amount of blended EVA80 along with lower quenching temperature. 相似文献
12.
Summary Trials were carried out in two years on a sandy loam and on a heavy clay soil with two cultivars to examine the potential
of chloride fertilization as a tool to reduce blackspot susceptibility of potatoes and to investigate other effects on yield
and quality. Blackspot susceptibility was significantly reduced in cv. Marijke, but not in cv. Bintje as a result of increasing
doses of applied chloride from 0 to 400 kg ha1. Dry matter concentration, assessed as under-water weight, was reduced by chloride
in both cultivars at the two locations. Fry colour of French fries was improved by chloride.
Applying 400 kg ha−1 Cl− to both soil types decreased net tuber yield >35 mm of cv. Bintje but not of cv. Marijke. Chloride caused slower emergence,
retarded crop development and less stems per plant on the sandy loam soil but not on the heavy clay soil. 相似文献
13.
Summary When nodal explants from sprouts grown from virus-free tubers of ten cultivars were propagated on half-strength Murashige
and Skoog medium, cvs Arsy, Nicola, Kennebec and Spunta grew best. Rooted plantlets, 5–8 cm tall, were transplanted from culture
vessels into pots containing soil, vermiculite and sand. They were weaned by growing in a glasshouse for about three weeks.
Over 90% of the plantlets survived and these were then planted in the field and protected against aphids by a double screen
(a large tunnel covering four adjacent small tunnels) and chemical treatments. Prebasic seed tubers thus obtained were virus-free
and production ranged from 49.9 t.ha−1 (‘Monalisa’) to 27.1 t.ha−1 (‘Majestic’).
A survey showed that ‘elite’ (near virus-free) seed could be produced from prebasic seed by early planting and early haulm
killing regardless of location, but late planting on the plains and normal planting dates on the mountains resulted in 1 to
5% virus infection levels acceptable only for certified seed. 相似文献
14.
15.
Summary The majority of isolates ofFusarium avenaceum caused dry rot on potato tubers; many were as pathogenic asF. coeruleum. Pathogenicity ofF. avenaceum was not related to the plant species from which the isolates originated. Tubers of potato cv. Cara were more susceptible
than those of cvs Romano or Maris Piper. Temperature (5–15° C) had no effect on lesion depth but lesions tended to be slightly
wider at the lowest temperature. Two isolates (of 61) from wheat and white lupin had a moderate level of resistance to thiabendazole.
The results are discussed in relation to the control of dry rot in stored potato tubers. 相似文献
16.
A. Richard Ejoh F. Tchouanguep Mbiapo Elie Fokou 《Plant foods for human nutrition (Dordrecht, Netherlands)》1996,49(2):107-112
The nutrient composition, ofColocasia esculenta flowers (CF) and leaves (CL), and the green fruits ofSolanum melongena (SM) were carried out as a means to determine their nutritional potential. Results showed that these food materials had high moisture and fiber levels which ranged between 888 and 906 g·kg–1; and 204 and 303 g·kg–1 dry weight (dw) for moisture and fiber respectively. The calorific values were between 3889 and 4001 kcals·kg–1 dw, while the total lipids ranged from 53 in CF to 71 g·kg–1 dw in SM. The leaves ofColocasia esculenta had the highest crude protein value of 307 g·kg–1 dw. The flowers had 149 g·kg–1 dw while SM had 138 g·kg–1 dw. The amino acid profile in the flowers and leaves ofColocasia esculenta in contrast to SM were balanced comparable to the reference FAO pattern. Ash values were high (ranging from 76 in SM to 98 g·kg–1 in CL) with potassium being the principal element. Iron and Zinc levels were also high especially in CF (with 303 and 82 mg·kg–1 dw respectively). These foods also contained moderate quantities of calcium, phosphorus and magnesium but were poor in manganese and copper. 相似文献
17.
Soybean inoculation: Dose, N fertilizer supplementation and rhizobia persistence in soil 总被引：1，自引：0，他引：1
Marta Albareda Dulce Nombre Rodríguez-Navarro Francisco J. Temprano 《Field Crops Research》2009,113(3):352-356
The effect of rate of application of Sinorhizobium (Ensifer) fredii SMH12 or Bradyrhizobium japonicum USDA110 inoculants on grain yields of soybean [Glycine max (L.) Merrill] cv. Osumi was studied in a field experiment laid out in Southern Spain. All inoculant doses tested (104, 105, 106 and 107 rhizobia/seed) produced higher seed yields than those obtained in un-inoculated plots. Increments in nodule dry weight, seed yield and seed N content were observed when the number of rhizobia applied to seed increased from 104 up to 107. The addition of N fertilizer to inoculated soybean plants (50 kg N/ha applied at R1 or R4 stage) did not increase seed yields in comparison with treatments that were only inoculated. Survival of strains SMH12 and USDA110 was monitorized for three years in two different soils of Southern Spain after soybean inoculation. Rhizobia survival was varied dependent on the soil and the rhizobia strain used. 相似文献
18.
Nevcihan Gursoy Bektas Tepe 《Plant foods for human nutrition (Dordrecht, Netherlands)》2009,64(2):135-140
This study was designed to examine the in vitro antimicrobial and antioxidant activities and the amount of total phenolics of the methanol extracts of Ballota rotundifolia L. and Teucrium chamaedrys C. Koch. In the case of antimicrobial activity tests, polar sub-fractions of the methanol extracts of plant species exhibited
weakest antimicrobial activity when compared with the non-polar ones. While, non-polar sub-fraction of B. rotundifolia showed moderate activity against A. lwoffii, C. perfringens and the yeasts, T. chamaedrys performed excellent activity pattern against all of the tested microorganisms. The sub-fractions were also screened for their
possible antioxidant activities by two complementary tests, namely DPPH free radical-scavenging and β-carotene/linoleic acid assays. Non-polar extracts of the plant species remained inactive in both test systems. On the other
hand polar extracts showed remarkable antioxidant activities. In DPPH system, free radical scavenging effect of T. chamaedrys was measured as 18.00 ± 1.42 μg.mg−1. It is extremely important to point out that, polar sub-fraction of T. chamaedrys is found as effective as the positive control BHT. Non-polar sub-fraction of T. chamaedrys found to have the highest total phenolic amount (97.12 ± 1.28 μg/mg). Results obtained from this experiment confirm the relationship
between the amount of phenolics and biological activities. 相似文献
19.
A simple and rapid method for the determination of naturally occurring, potentially hazardous glycoalkaloids (GAs) in potatoes
and their products has been developed. The procedure is based on the on-line solid-phase extraction of the acetic acid extracts
from potato products and combined with liquid chromatography (LC)-mass spectrometry (MS) in a fully automated system (Symbiosis™,
Spark Holland Instruments, Emmen, The Netherlands). As sorbent material HySphere™ 18HD was used for alkaloid enrichment. GAs
were eluted with the LC gradient and directly analysed by MS. Detection of the analytes was achieved in the sensitive multiple
reaction monitoring mode using two characteristic ions (m/z 98 as a qualifier for GAs and m/z 868.3 as a quantifier for α-solanine or m/z 852.4 for α-chaconine). Typical validation data for method precision (v
k α-solanine = 5.3–6.5, v
k α-chaconine = 3.4–15.4), accuracy (average recovery of α-solanine = 84%, average recovery of α-chaconine = 87%) and linearity
over the range from 1 to 1,000 ng ml−1 (R
2 = 0.9915 for α-solanine, R
2 = 0.9939 for α-chaconine) with detection limits of 0.3 ng ml−1 for α-chaconine and 0.5 ng ml−1 for α-solanine were obtained. GA contents of commercial potato products were determined by the new on-line method and afterwards
compared with those obtained with an established high-performance LC routine procedure. Better performance of the on-line
procedure was obvious from the standard deviations of both methods. Other advantages included a strong reduction of overall
analysis time, human intervention and solvent consumption as well as waste production. The time required for the on-line analysis
was 5 min, which would allow processing of almost 100 samples in 8 h. 相似文献
20.
Summary Over 2 years, seed tubers or stems were inoculated withFusarium sulphureum Schlecht. (F. sambucinum Fuckel f. 6 Wollenw.) and the incidence of dry rot on daughter tubers assessed by standardised wound tests. The amount of
stem and soil inoculum was also measured in one year.
Inoculating stem bases resulted in greater concentrations of spores on the stem bases, greater soil populations at harvest
and more dry rot on tubers than inoculating the seed tuber. Overall, the incidence of dry rot and the amount of stem and soil
inoculum was similar for the three methods of haulm destruction: cutting and removing the stems, applying sulphuric acid or
applying diquat dibromide to the growing plants. 相似文献