Production of Sporangia by Phytophthora cinnamomi in Forest Soils

1979 ◽  
Vol 27 (6) ◽  
pp. 693 ◽  
Author(s):  
G Weste ◽  
K Vithanage
Keyword(s):  
Seasonal Variation ◽  
Forest Soils ◽  
Phytophthora Cinnamomi ◽  
Sandy Soils ◽  
Garden Soil ◽  
First Year ◽  
Soil Sterilization ◽  
Pilot Survey ◽  
Significant Seasonal Variation ◽  
Soil Temperatures

Sporangial production by Phytophthora cinnamomi was investigated during a 3-year period for three types of conducive forest soils. A pilot survey conducted during the first year included garden soil and demonstrated that all forest soils tested stimulated sporangial production, that the stimulus was reduced by soil sterilization, and that soils without P. cinnamomi provided a greater stimulus than soils from diseased sites. For the final 2 years of the investigation soil and root samples were collected from diseased plants at 3- monthly intervals, and soil filtrates were tested for their ability to stimulate sporangial production. Soil matric water potentials and soil temperatures were recorded concurrently. Three factors which influenced the soil and indirectly affected sporangial formation were soil temperature, soil matric water potential and the presence of a stimulus produced by certain living microorganisms. Sporangial production showed highly significant seasonal variation with maxima in spring. No sporangia were produced in summer. Differences in the numbers of sporangia produced in response to the different soil filtrates were also highly significant, the highest numbers being formed in response to sandy soils of Wilson's Promontory. These results, particularly the large release of zoospores during spring, are of great importance in the spread of disease, and should be considered in relation to roadmaking and forestry in diseased areas.

Seasonal Variation in Numbers of Chlamydospores in Victorian Forest Soils Infected With Phytophthora cinnamomi

1978 ◽  
Vol 26 (5) ◽  
pp. 657 ◽  
Author(s):  
G Weste ◽  
K Vithanage
Keyword(s):  
Seasonal Variation ◽  
Soil Water ◽  
Forest Soils ◽  
Phytophthora Cinnamomi ◽  
Soil Water Potential ◽  
Native Forest ◽  
Forest Sites ◽  
Significant Seasonal Variation ◽  
Different Types ◽  
Soil Temperatures

Chlamydospore numbers were counted for 2 years on replicated soil samples from three different types of naturally infected Victorian native forest. Soil temperatures and soil water potentials were recorded concurrently. A highly significant seasonal variation in chlamydospore numbers was observed with maxima from summer to autumn and minima from winter to spring. There was little variation either between replicates or between different forest soils in winter and spring counts, but there was highly significant variation between different forest sites during the large summer and autumn counts. At this period sandy soil contained five to 12 times the number of chlamydo- spores found in other soils. For example, in autumn 1977,286 chlamydospores were recorded per 50 g sample from deep sandy soils compared with 31 for krasnozem and 17 for shallow duplex soils. At this period soil temperatures were similar but the soil water potential for the duplex soil was very low (-82 bars).

Microbial populations of three forest soils: seasonal variations and changes associated with Phytophthora cinnamomi

1977 ◽  
Vol 25 (4) ◽  
pp. 377 ◽  
Author(s):  
G Weste ◽  
K. Vithanage
Keyword(s):  
Forest Soils ◽  
Phytophthora Cinnamomi ◽  
Severe Disease ◽  
Organic Content ◽  
Microbial Populations ◽  
Garden Soil ◽  
Soil Temperatures ◽  
Disease Extension ◽  
Pathogen Populations ◽  
Soil Microbial Population

Microbial populations of three forest soils were assayed by a dilution plate procedure and compared with garden soil. The forest soils were selected from areas subjected to die-back disease caused by Phytophthora cinnamomi Rands, and were from sites for which pathogen populations, soil temperatures, rainfall and soil water potentials were concurrently recorded. Forest soils showed low microbial populations compared with garden soil. This was associated with low organic content, low nitrogen status and poor water-holding capacity. Areas with severe disease and rapid disease extension had a small soil microbial population, particuarly of actinomycetes, compared with soil from areas with moderate disease and slow disease extension. Microbial populations were lowest in spring and autumn when P. cinnamomi was most active, and zoospore production, dispersal and infection was maximal. Microbial populations of forest soil were reduced following die-back; and the reduction of disease was highly significant (P < 0.01) for the Brisbane Ranges where plant mortality was high and the percentage of bare ground increased.

Feeding, reproduction and growth in the crowned snake

1998 ◽  
Vol 19 (3) ◽  
pp. 311-318 ◽  
Author(s):  
Otavio A.V. Marques ◽  
Giuseppe Puorto
Keyword(s):  
Seasonal Variation ◽  
Natural History ◽  
Rainy Season ◽  
Sexual Maturity ◽  
Southeastern Brazil ◽  
First Year ◽  
Main Prey ◽  
Significant Seasonal Variation ◽  
Body Sizes ◽  
History Of

AbstractThe crowned snake Tantilla melanocephala is a small fossorial sonorine snake, widely distributed through South America. Dissection of 186 specimens, combined with observations of captive specimens, provided information on the natural history of this species in southeastern Brazil. Females attained larger body sizes than males. Apparently T. melanocephala forage at night for active prey. Centipedes of the genus Otostigmus were the main prey item. These centipedes are subdued by injection of venom. Data from preserved specimens showed no significant seasonal variation in the number of collected snakes. Reproduction seemed to be highly seasonal with vitellogenesis occurring from onset to the middle of the rainy season and hatching at the end of the rainy season. Clutch size ranged from one to three and was correlated with female body length. Neonates measured 10-12 cm snout-vent length and juveniles attained about 17.5 cm SVL during the first year. Apparently males attain sexual maturity at an age of about 10 months and females at about 20 months.

scholarly journals Variations in Organic Carbon Content and Dehydrogenases Activity in Post-Agriculture Forest Soils: A Case Study in South-Western Pomerania

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 459
Author(s):  
Katarzyna Wiatrowska ◽  
Jolanta Komisarek ◽  
Janusz Olejnik
Keyword(s):  
Seasonal Variation ◽  
Organic Carbon ◽  
Forest Soils ◽  
Stand Age ◽  
Organic Carbon Content ◽  
Sharp Drop ◽  
The North ◽  
Significant Seasonal Variation ◽  
Significant Difference ◽  
Dehydrogenases Activity

Temperate forest soils of Europe are regarded as an important sink of carbon and thought to have potential to sequester CO2 from atmosphere. However, there are insufficient data not only on organic carbon (OC) content in forest soils and its temporal changes but also on microbiological activity and especially their relationship to carbon turnover. In this study seven research plots were located on afforested land in the north-western part of Poland in Tuczno Forest District (Western Pomerania) in order to examine seasonal variation in OC content and dehydrogenases activity (DHA) during 2012–2016. Based on the studies conducted, statistically significant seasonal variation of the OC content was observed. Higher amounts of OC in the A horizon were observed during spring and autumn seasons and lower in summer. However, no seasonal variation on OC content was observed in the organic horizon (O horizon). Although DHA is thought to exhibit strong seasonal variability, no seasonal variation on DHA was observed. However, a statistically significant difference was observed among studied years (2012–2016), a sharp drop of DHA was noted from spring 2014. Statistical analyses revealed that OC content in soils was a function of forest stand age and progressing acidification of soil. Moreover, OC content in O horizon was negatively correlated with soil moisture and DHA, suggesting that periods with higher microbial activity lead to lower accumulation of carbon in the O horizon. During 2012–2016 only for the O horizon was an increase in OC content was observed.

scholarly journals Hydrogeochemistry and surface water quality assessment of IB valley coalfield area, India

2021 ◽  
Vol 11 (9) ◽  
Author(s):  
Bishnu Prasad Sahoo ◽  
Himanshu Bhushan Sahu ◽  
Dhruti Sundar Pradhan
Keyword(s):  
Water Quality ◽  
Heavy Metal ◽  
Seasonal Variation ◽  
Surface Water ◽  
Water Samples ◽  
Nickel Aluminum ◽  
Acid Mine ◽  
Significant Seasonal Variation ◽  
Cadmium Selenium ◽  
High Degree

AbstractCoal mining and ancillary activities have the potential to cause water pollution characterized by acid mine drainage, acid mine leachates, extreme pH conditions and heavy metal contaminations. In the present work, 33 water samples in premonsoon and 34 water samples in monsoon were collected from the surface water bodies of Ib Valley coalfield, India for hydrogeochemical analysis. In premonsoon, pH, TSS, Turbidity, DO, BOD, COD, Magnesium, Cadmium, Selenium, Nickel, Aluminum and in monsoon, pH, TSS, Turbidity, DO, BOD, COD, Iron, Cadmium, Selenium, Nickel and Aluminum were nonconforming to the permissible limit set by the Bureau of Indian Standards, World Health Organisation and Ministry of Environment, Forest and Climate Change, Government of India. The average BOD/COD ratio of less than 0.6 in both seasons indicated Ib valley coalfield water was not fairly biodegradable. The analysis of variance (ANOVA) revealed that significant seasonal variation (p < 0.05) was observed in the hydro-chemical parameters viz. TSS, turbidity, redox potential, acidity, total hardness, bicarbonate alkalinity, chloride, sulfate, nitrate, sodium, calcium, magnesium, iron, cadmium, chromium and magnesium during the entire sampling period. Whereas, no significant seasonal variation (p > 0.05) was observed in pH, EC, TDS, DO, BOD, residual chlorine, COD, oil and grease, fluoride, potassium, zinc, copper, selenium, nickel, aluminum, boron, silica, temperature, salinity, cyanide and phenol. Water Quality Index revealed that 39.39% and 35.29% samples belong to poor water quality category in premonsoon and monsoon, respectively. As per Heavy Metal Pollution Index, Degree of Contamination (Cd) and Heavy metal evaluation index, medium degree of pollution were exhibited by 51.52%, 30.30% and 45.45% samples in premonsoon and 20.59%, 35.29% and 26.47% samples in monsoon. Whereas, 5.88%, 2.94% and 5.88% samples were having high degree of pollution in monsoon and 15.15% samples caused high degree of pollution with respect to Cd in premonsoon. However, EC, Na%, PI, SAR and RSC values suggested that the water can be used for irrigation. Water type of the region had been found to be Ca–Mg–Cl–SO4 by Piper diagram.

Seasonal Variability in Middepth Gyral Circulation Patterns in the Central East/Japan Sea as Revealed by Long-Term Argo Data

2016 ◽  
Vol 46 (3) ◽  
pp. 937-946 ◽  
Author(s):  
Sok Kuh Kang ◽  
Young Ho Seung ◽  
Jong Jin Park ◽  
Jae-Hun Park ◽  
Jae Hak Lee ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Seasonal Variability ◽  
Japan Sea ◽  
Circulation Pattern ◽  
Japan Basin ◽  
Wind Stress Curl ◽  
Argo Data ◽  
Circulating Water ◽  
Significant Seasonal Variation ◽  
Water Columns

AbstractTrajectories of Argo floats deployed in the East/Japan Sea from 2001 to 2014 reveal that the middepth gyral circulation pattern of the Japan basin, the central part of the East/Japan Sea, undergoes a seasonal variation. The middepth circulation of the Japan basin is found to be characterized usually by the gyres trapped to the east of the Bogorov Rise (E-gyres) and those extending farther westward into the whole basin (BW-gyres). The E-gyre trajectories are generally associated with the turning of the floats toward deeper regions off the isobaths. This occurs in winter either on the northern or eastern side of the eastern Japan basin. It seems that the upstream part of the otherwise BW-gyre is subject to a strong negative wind stress curl in winter, and there the circulating water columns are driven toward the deeper region, thus triggering the formation of the E-gyre. The topographic effect associated with the Bogorov Rise seems to interfere thereafter in the process of determining the passage of the E-gyre. Otherwise, the water columns continue to flow along the isobaths, hence maintaining the BW-gyre. To the knowledge of the authors, this is the first observational evidence of seasonal variability in the middepth gyral circulation pattern in the East/Japan Sea. It suggests that oceanic middepth circulation, usually known to be quasi steady or slowly varying on climatological time scales, might also undergo a significant seasonal variation as it does in the East/Japan Sea.

scholarly journals Physico-chemical attributes of water of Hakaluki Haor, Sylhet, Bangladesh

2016 ◽  
Vol 3 (2) ◽  
pp. 67-72
Author(s):  
Md Tajul Islam ◽  
M Mahfuzur Rahman ◽  
Hassan Mahmud
Keyword(s):  
Water Quality ◽  
Seasonal Variation ◽  
Water Samples ◽  
Water Quality Assessment ◽  
Inorganic Pollutants ◽  
Chemical Parameters ◽  
Ph Values ◽  
Physico Chemical ◽  
Significant Seasonal Variation ◽  
Chemical Attributes

Water quality assessment has been carried out in the Hakaluki Haor of greater Sylhet district during May, 2013 to February, 2014. Water samples were collected from 5 spots during 4 seasons and a total of 15 physico-chemical parameters were studied. Significant seasonal variation was observed in all seasons among physico-chemical parameters. pH values varied from 5.9 - 7.1, water temperature varied from 23.7 – 26.7OC, transference varied from 23-53 cm, TSS varied from 18.1-192 mg/l, TDS varied 25-193.5 mg/l, EC varied from 30-680 ?s/cm , DO content of water varied from 4.6 - 5.6mg/l, BOD varied from 0.2-2.614 mg/l, COD varied from 38-312 mg/l, NO3-N varied from 0.1-30.4 mg/l, NH3 varied from 0.9-2.18 mg/l, alkalinity varied from 12-42 mg/l and PO4 varied from 0.9 -13.4 (mg/l). Agricultural and inorganic pollutants have been observed as the main causes of the Haor water pollution.Jahangirnagar University J. Biol. Sci. 3(2): 67-72, 2014 (December)

scholarly journals Data reduction and calibration for LAMOST survey

2013 ◽  
Vol 9 (S298) ◽  
pp. 428-428 ◽  
Author(s):  
Ali Luo ◽  
Jiannan Zhang ◽  
Jianjun Chen ◽  
Yihan Song ◽  
Yue Wu ◽  
...  
Keyword(s):  
Data Reduction ◽  
Effective Temperature ◽  
Type Star ◽  
First Year ◽  
General Survey ◽  
Analysis Pipeline ◽  
Spectra Analysis ◽  
Pilot Survey ◽  
Fitting Method ◽  
Data Policy

AbstractThere are three data pipelines for LAMOST survey. The raw data is reduced to one dimension spectra by the data reduction pipeline(2D pipeline), the extracted spectra are classified and measured by the spectral analysis pipeline(1D pipeline), while stellar parameters are measured by LASP pipeline.(a) The data reduction pipeline. The main tasks of the data reduction pipeline include bias calibration, flat field, spectra extraction, sky subtraction, wavelength calibration, exposure merging and wavelength band connection.(b) The spectra analysis pipeline. This pipeline is designed to classify and identify objects from the extracted spectra and to measure their redshift (or radial velocity). The PCAZ (Glazebrook et al. 1998) method is applied to do the classification and redshift measurement.(c) Stellar parameters LASP. Stellar parameters pipeline (LASP) is to estimate stellar atmospheric parameters, e.g. effective temperature Teff, surface gravity log g, and metallicity [Fe/H], for F, G and K type stars. To effectively determine those fundamental stellar measurements, three steps with different methods are employed. The first step utilizes the line indices to approximately define the effective temperature range of the analyzed star. Secondly, a set of the initial approximate values of the three parameters are given based on template fitting method. Finally, we exploit ULySS (Koleva et al. 2009) to give the final values of parameters through minimizing the χ 2 value between the observed spectrum and a multidimensional grid of model spectra which is generated by an interpolating of ELODIE library. There are two other classification for A type star and M type star. For A type star, standard MK system is employed (Gray et al. 2009) to give each object temperature class and luminosity type. For M type star, they are classified into subclasses by an improved Hammer method, and metallicity of each objects is also given.During the pilot survey, algorithms were improved and the pipelines were tested. The products of LAMOST survey will include extracted and calibrated spectra in FITS format, a catalog of FGK stars with stellar parameters, a catalog of M dwarf with subclass and metallicity, and a catalog of A type star with MK classification. A part of the pilot survey data, including about 319 000 high quality spectra with SNR > 10, a catalog of stellar parameters of FGK stars and another catalog of a subclass of M type stars have been released to the public in August 2012 (Luo et al. 2012). The general survey started from October 2012, and completed the first year survey. The formal data release one (DR1) is being prepared, which will include both pilot survey and first year general survey, and planed to be released under the LAMOST data policy.

scholarly journals Mucormycosis in the Eastern Mediterranean: a seasonal disease

2005 ◽  
Vol 134 (2) ◽  
pp. 341-346 ◽  
Author(s):  
M. R. AL-AJAM ◽  
A. R. BIZRI ◽  
J. MOKHBAT ◽  
J. WEEDON ◽  
L. LUTWICK
Keyword(s):  
Seasonal Variation ◽  
Fungal Infection ◽  
Pulmonary Infection ◽  
Pattern Analysis ◽  
Eastern Mediterranean ◽  
Seasonal Pattern ◽  
Atmospheric Concentration ◽  
Tel Aviv ◽  
Significant Seasonal Variation ◽  
Immunocompromised Hosts

Mucormycosis is a fairly rare fungal infection caused by ubiquitous fungi of the order Mucorales and primarily affects immunocompromised hosts. A series of 16 cases of invasive mucormycosis admitted to three referral centres in Beirut, Lebanon between 1981 and 1999 is described. It includes 12 patients with rhinocerebral, three with cutaneous, and one with pulmonary infection. Onset of symptoms occurred in the summer and autumn in 15 out of 16 patients, showing a statistically significant seasonal variation (P=0·007) A recent report of 19 patients from Tel Aviv describes a strikingly similar seasonal pattern. Studies on atmospheric concentration of Mucorales spores in the Eastern Mediterranean are lacking. Weather pattern analysis in Beirut revealed clustering of onset of invasive mucormycosis at the end of a dry, warm period, which begins around May and ends in October. Mucormycosis incidence appears to be seasonal in the Eastern Mediterranean.

Amelioration of subsurface acidity in sandy soils in low rainfall regions .2. Changes to soil solution composition following the surface application of gypsum and lime

Soil Research ◽  
1994 ◽  
Vol 32 (4) ◽  
pp. 847 ◽  
Author(s):  
CDA Mclay ◽  
GSP Ritchie ◽  
WM Porter ◽  
A Cruse
Keyword(s):  
Ionic Strength ◽  
Soil Solution ◽  
Ion Pairs ◽  
Chemical Properties ◽  
Sandy Soils ◽  
Soil Surface ◽  
Field Trials ◽  
Annual Rainfall ◽  
First Year ◽  
Solution Composition

Two field trials were sampled to investigate the changes to soil solution chemical properties of a yellow sandplain soil with an acidic subsoil following the application of gypsum and lime to the soil surface in 1989. The soils were sandy textured and located in a region of low annual rainfall (300-350 mm). Soil was sampled annually to a depth of 1 m and changes in soil solution composition were estimated by extraction of the soil with 0.005 M KCl. Gypsum leaching caused calcium (Ca), sulfate (SO4) and the ionic strength to increase substantially in both topsoil and subsoil by the end of the first year. Continued leaching in the second year caused these properties to decrease by approximately one-half in the topsoil. Gypsum appeared to have minimal effect on pH or total Al (Al-T), although the amount of Al present as toxic monomeric Al decreased and the amount present as non-toxic AlSO+4 ion pairs increased. Magnesium (Mg) was displaced from the topsoil by gypsum and leached to a lower depth in the subsoil. In contrast, lime caused pH to increase and Al to decrease substantially in the topsoil, but relatively little change to any soil solution properties was observed in the subsoil. There was an indication that more lime may have leached in the presence of gypsum in the first year after application at one site. Wheat yields were best related to the soil acidity index Al-T/EC (where EC is electrical conductivity of a 1:5 soil:water extract), although the depth at which the relationship was strongest in the subsoil varied between sites. The ratio Al-T/EC was strongly correlated with the activity of monomeric Al species (i.e. the sum of the activities of Al3+, AlOH2+ and Al(OH)+2 in the soil solution. An increase in the concentration of sulfate in the subsoil solution (which increased the ionic strength, thereby decreasing the activity of Al3+, and also increased the amount of Al present as the AlSO+4 ion pair) was probably the most important factor decreasing Al toxicity to wheat. The results indicated that gypsum could be used to increase wheat growth in aluminium toxic subsoils in sandy soils of low rainfall regions and that a simple soil test could be used to predict responses.

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