Comparative Morphology and Behaviour of A1 and A2 Isolates of Phytophthora cinnamomi

1974 ◽  
Vol 22 (3) ◽  
pp. 461 ◽  
Author(s):  
CJ Shepherd ◽  
BH Pratt ◽  
PA Taylor
Keyword(s):  
Growth Rate ◽  
Plant Communities ◽  
Phytophthora Cinnamomi ◽  
Comparative Morphology ◽  
Native Plant ◽  
Temperature Growth ◽  
General Similarity ◽  
Similar Temperature ◽  
The Mean ◽  
Osmotic Potentials

Studies of morphology, physiological behaviour and pathogenicity indicated that some significant differences existed between isolates of the A1 and A2 compatibility types of Phytophthora cinnamomi from native plant communities in Australia. The majority of A1 isolates produced zoosporangia more rapidly and in greater numbers than A2 isolates, and zoosporangia were produced evenly on mycelial discs of A1 isolates whereas they occurred mostly at the perimeter of similar discs in the case of A2 isolates. Chlamydospores were produced more rapidly by A1 than A2 isolates, and in the former tended to be of an even size and were frequently single, whereas in A2 isolates the size was extremely variable and production was usually in clusters. Both compatibility types showed similar temperature-growth optima, but the mean growth rate of A1 isolates, over the range 15-30°C, was less than that of A2 isolates. Both types responded similarly to high temperature treatments and to a range of osmotic potentials and both showed similar pathogenicity to lupin and Pinus radiata seedlings. While both compatibility types showed similar reactions to a number of inhibitors, the growth of A2 isolates was inhibited more by rose bengal and pyronin G than that of A1 isolates. Thus, although significant differences were recorded, there was a general similarity of behaviour of isolates of both compatibility types and there were no striking differences from the recorded behaviour of the fungus in other countries.

Temperature-Growth Relations and Genetic Diversity of A2 Mating-Type Isolates of Phytophthora cinnamomi in Australia

1974 ◽  
Vol 22 (2) ◽  
pp. 231 ◽  
Author(s):  
CJ Shepherd ◽  
BH Pratt
Keyword(s):  
Growth Rate ◽  
First Generation ◽  
Phytophthora Cinnamomi ◽  
Phytophthora Species ◽  
Temperature Growth ◽  
Field Isolates ◽  
Place Of Origin ◽  
Successive Generations ◽  
Cardinal Temperatures ◽  
Range Of Values

Determinations of cardinal temperatures for growth on various media of 50 Australian isolates of Phytophthova cinnamomi showed that growth did not occur outside the range 5-35°C. The range of temperatures at which growth optima occurred varied according to the isolate and medium used and encompassed the whole range of values reported by overseas authors. Growth rates of 361 isolates on corn meal agar at 25°C varied within the range 4.7-10.5 mm/day. There was no correlation between optimum temperature and whether isolates were slow- or fastgrowing or their place of origin. Fast-growing isolates (6-11 mm/day) were obtained from all States, but slower-growing isolates (<6 mm/day) were obtained only from southern and western regions of Australia. Populations from different regions of Australia exhibited different growth rate parameters. The variability of mycelial isolates in culture was studied by examining differences in growth rate among replicated parent, single-zoospore, single-zoosporangium and single terminal-hyphal isolates. Extensive variation was found among first generation single-zoospore progenies of field isolates, with lesser variation among progeny of single zoosporangia, terminal hyphal cultures and second and third generation zoospore derivatives. The origin of this variation is discussed and it is suggested that field isolates are heterokaryotic, since zoospores proved to be predominantly uninucleate. When various Phytophthora species were incubated at temperatures above those at which growth was possible and then returned to 25°C, their subsequent ability to resume growth depended on the particular time-temperature combination used. Considerable variation of response was found among a number of isolates of P. cinnamomi and, following the establishment of single zoospore isolates, the potential variability of field isolates was shown to persist through successive generations of zoospore propagation. It is suggested that a cytoplasmic mechanism of inheritance may be responsible for this variation.

The long-term ability of phosphite to control Phytophthora cinnamomi in two native plant communities of Western Australia

2001 ◽  
Vol 49 (6) ◽  
pp. 761 ◽  
Author(s):  
K. M. Tynan ◽  
C. J. Wilkinson ◽  
J. M. Holmes ◽  
B. Dell ◽  
I. J. Colquhoun ◽  
...  
Keyword(s):  
Plant Species ◽  
Plant Communities ◽  
Western Australia ◽  
Foliar Application ◽  
Phytophthora Cinnamomi ◽  
Native Plant ◽  
In Planta ◽  
Eucalyptus Marginata ◽  
Application Rates ◽  
The Impact

This study examined the ability of foliar applications of the fungicide phosphite to contain colonisation of Phytophthora cinnamomi in a range of plant species growing in natural plant communities in the northern sandplain and jarrah (Eucalyptus marginata) forest of south-western Australia. Wound inoculation of plant stems with P. cinnamomi was used to determine the efficacy of phosphite over time after application. Colonisation by P. cinnamomi was reduced for 5–24 months after phosphite was applied, depending on the concentration of phosphite used, plant species treated and the time of phosphite application. Plant species within and between plant communities varied considerably in their ability to take up and retain phosphite in inoculated stems and in the in planta concentrations of phosphite required to contain P. cinnamomi. As spray application rates of phosphite increased from 5 to 20 g L–1, stem tissue concentrations increased, as did the ability of a plant species to contain P. cinnamomi. However, at application rates of phosphite above 5 g L–1 phytotoxicity symptoms were obvious in most species, with some plants being killed. So, despite 10 and 20 g L–1 of phosphite being more effective and persistent in controlling P. cinnamomi, these rates are not recommended for application to the plant species studied. The results of this study indicate that foliar application of phosphite has considerable potential in reducing the impact of P. cinnamomi in native plant communities in the short-term. However, in order to maintain adequate control, phosphite should be sprayed every 6–12 months, depending on the species and/or plant community.

scholarly journals The Origin and Distribution of Phytophthora Cinnamomi Rands in Australian Native Plant Communities and the Significance of Its Association With Particular Plant Species

1973 ◽  
Vol 26 (3) ◽  
pp. 559 ◽  
Author(s):  
BH Pratt ◽  
WA Heather
Keyword(s):  
Plant Species ◽  
Plant Communities ◽  
Phytophthora Cinnamomi ◽  
Disease Association ◽  
Native Plant ◽  
Australian Native Plant

The origin, distribution, and disease association of P. cinnamomi in native plant communities in Australia has been examined.

Long-term dynamics and destruction of marsh vegetation in the Kolokolkova Bay of the Barents Sea

2012 ◽  
pp. 66-77 ◽  
Author(s):  
I. A. Lavrinenko ◽  
O. V. Lavrinenko ◽  
D. V. Dobrynin
Keyword(s):  
Species Composition ◽  
Plant Communities ◽  
Barents Sea ◽  
Mean Value ◽  
Marsh Vegetation ◽  
Composition And Structure ◽  
The Mean ◽  
Species Composition And Structure

The satellite images show that the area of marshes in the Kolokolkova bay was notstable during the period from 1973 up to 2011. Until 2010 it varied from 357 to 636 ha. After a severe storm happened on July 24–25, 2010 the total area of marshes was reduced up to 43–50 ha. The mean value of NDVI for studied marshes, reflecting the green biomass, varied from 0.13 to 0.32 before the storm in 2010, after the storm the NDVI decreased to 0.10, in 2011 — 0.03. A comparative analysis of species composition and structure of plant communities described in 2002 and 2011, allowed to evaluate the vegetation changes of marshes of the different topographic levels. They are fol­lowing: a total destruction of plant communities of the ass. Puccinellietum phryganodis and ass. Caricetum subspathaceae on low and middle marches; increasing role of halophytic species in plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. typicum on middle marches; some changes in species composition and structure of plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. festucetosum rubrae on high marches and ass. Parnassio palustris–Salicetum reptantis in transition zone between marches and tundra without changes of their syntaxonomy; a death of moss cover in plant communities of the ass. Caricetum mackenziei var. Warnstorfia exannulata on brackish coastal bogs. The possible reasons of dramatic vegetation dynamics are discussed. The dating of the storm makes it possible to observe the directions and rates of the succession of marches vegetation.

The incidence of central serous chorioretinopathy in the population of Kazan: Results of a retrospective epidemiological analysis for 2009–2018

2020 ◽  
pp. 30-33
Author(s):  
D. R. Аgliullin ◽  
G. R. Khasanova ◽  
E. A. Abdulaeva ◽  
S. T. Agliullina ◽  
A. N. Amirov ◽  
...  
Keyword(s):  
Growth Rate ◽  
Central Serous Chorioretinopathy ◽  
Morbidity Rate ◽  
Seasonal Prevalence ◽  
Upward Trend ◽  
Epidemiological Analysis ◽  
Significant Upward Trend ◽  
Track Record ◽  
Minimum Age ◽  
The Mean

Objective: To assess the incidence of central serous chorioretinopathy (CSC) through the example of a large industrial Russian city.Methods: A retrospective analysis of CSC of Kazan population for 2009–2018 has been done.Results: From 2019 to 2018, 831 new cases of CSC were registered in Kazan. A statistically significant upward trend with growth rate 105.2% and accession rate 5.2% was typical for the annual track record. The mean age of patients was 50 years, the minimum age was 14 years, the maximum age was 87 years. A statistically significant upward trend was detected in track record of incidence in groups of 30–39-year-old and 40–49-year-old. Seasonal increase of the incidence was recorded in February, March, April, October, and November.Conclusions: The upward trend and seasonal prevalence are typical for longterm morbidity of CSC in Kazan. The highest morbidity rate of CSC and statistically significant upward trend of its incidence in track record were recorded in the age of 30–39. 

Continuous Precipitation of Lead Iodide

1994 ◽  
Vol 59 (7) ◽  
pp. 1503-1510
Author(s):  
Stanislav Žáček ◽  
Jaroslav Nývlt
Keyword(s):  
Growth Rate ◽  
Particle Size ◽  
Crystal Size ◽  
Crystal Growth Rate ◽  
Laboratory Model ◽  
Lead Iodide ◽  
Secondary Nucleation ◽  
Equimolar Ratio ◽  
Continuous Precipitation ◽  
The Mean

Lead iodide was precipitated from aqueous solutions of 0.015 - 0.1 M Pb(NO3)2 and 0.03 - 0.2 M KI in the equimolar ratio using a laboratory model of a stirred continuous crystallizer at 22 °C. After reaching the steady state, the PbI2 crystal size distribution was measured sedimentometrically and the crystallization kinetics was evaluated based on the mean particle size. Both the linear crystal growth rate and the nucleation rate depend on the specific output of the crystallizer. The system crystallization constant either points to a significant effect of secondary nucleation by the mechanism of contact of the crystals with the stirrer blade, or depends on the concentrations of the components added due to the micromixing mechanism.

High temperature growth rate in MOCVD growth of AlGaAs

1984 ◽  
Vol 68 (1) ◽  
pp. 169-175 ◽  
Author(s):  
Tetsuo Soga ◽  
Yasuhito Takahashi ◽  
Shiro Sakai ◽  
Masayoshi Umeno
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Temperature Growth ◽  
Mocvd Growth

A comparative study on the nursery culture of hatchery-reared sub-adult cupped oyster, Crassostrea iredalei (Faustino, 1932), in an earthen pond and a mangrove canal

2018 ◽  
Vol 26 (4) ◽  
pp. 217-222
Author(s):  
Premwadee Chueachat ◽  
Woraporn Tarangkoon ◽  
Suwat Tanyaros
Keyword(s):  
Growth Rate ◽  
Comparative Study ◽  
Condition Index ◽  
Daily Growth ◽  
Nursery Culture ◽  
Absolute Growth Rate ◽  
Significant Difference ◽  
Adult Oyster ◽  
Absolute Growth ◽  
The Mean

Abstract A comparative study on the nursery culture of the spat of the tropical oyster, Crassostrea iredalei, in an earthen pond and a mangrove canal was conducted over two months. The results revealed no differences in the absolute growth rate determined by shell width between the two culture sites (P < 0.05). Sub-adult oysters cultured in the mangrove canal showed a higher absolute growth rate in shell length and a higher daily growth rate than the oysters cultured in the earthen pond (P < 0.05). The mean survival rate of sub-adult oysters cultured in the earthen pond (99.8 ± 0.2%) was significantly higher than for those cultured in the mangrove canal (66.7 ± 31.4%). Decreased density from the loss of sub-adult oyster nursery culture in the mangrove canal led to higher growth performance than in the earthen pond. However, no difference was found for the fraction of oysters larger or smaller than 5 cm for the two culture sites (P < 0.05). A significant difference was noted in the Condition Index (CI) between the two culture sites (P < 0.05). The high primary productivity in mangroves is a major supporter of higher CI in sub-adult oysters cultured in mangrove canals versus in earthen ponds. Water exchange in the earthen pond to maintain calcium and magnesium concentrations resulted in no differences in the shell compressibility of sub-adult oysters compared with those cultured in the mangrove canal.

Relationship between the gas production profiles of mixtures of hay and maize and the patterns of rumen fermentation observed in sheep fed those mixtures

1998 ◽  
Vol 1998 ◽  
pp. 63-63
Author(s):  
C. Rymer ◽  
D.I. Givens
Keyword(s):  
Growth Rate ◽  
Feed Intake ◽  
Rumen Fermentation ◽  
Gas Production ◽  
Post Feeding ◽  
Molar Proportion ◽  
Rumen Ph ◽  
The Mean

The gas production (GP) technique has been developed to assess dynamics of ruminant digestion. Relationships have been observed between a feed's GP profile and in vivo parameters such as digestibility (Khazaal et al., 1993), feed intake and growth rate (Blümmel and Ørskov, 1993), and in situ degradability (Sileshi et al., 1997). However, there are few studies which relate GP data to the in vivo pattern of rumen fermentation (in terms of the rate of pH decline 2 h post-feeding and the mean rumen pH, concentration of total VFA and molar proportion of individual VFA). The object of this experiment was to determine whether such a relationship existed between a feed's GP profile and the pattern of rumen fermentation observed in animals fed that feed.

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