scholarly journals Influence of pH and Matric Potential on Germination of Cephalosporium gramineum Conidia

Plant Disease ◽  
1998 ◽  
Vol 82 (9) ◽  
pp. 975-978 ◽  
Author(s):  
Cynthia A. Blank ◽  
Timothy D. Murray

Germination of Cephalosporium gramineum conidia in soil was up to twofold greater at -0.064 MPa than at -0.037 and -0.007 MPa when incubated at 5°C for 2 days. Soil pH from 4.7 to 7.5 did not have a significant influence on germination of conidia and the interaction between soil pH and matric potential on germination was not significant. Soil fungistasis, which was previously observed for conidia of C. gramineum, was not observed in these studies. Germination of conidia on mineral salts agar containing phosphate buffer was significantly less at pH 4.5 than at 5.5, 6.5, or 7.5 at 5°C in one of two experiments; however, pH had no influence on germination at 10 or 20°C in two experiments. Although Cephalosporium stripe is more severe under conditions of high soil moisture and low soil pH, increased germination of conidia in response to these factors does not explain the observed increase in disease.

1988 ◽  
Vol 66 (11) ◽  
pp. 2299-2304 ◽  
Author(s):  
T. D. Murray

Radial growth of three isolates of Cephalosporium gramineum was fastest at or below pH 6.0 and slowest at pH 7.5 at 20 °C on corn meal agar and mineral salts agar adjusted to pH values from 4.5 to 7.5 with either phosphate or citrate–phosphate buffer. Interactions among medium, pH, buffer, and isolate occurred. On media containing phosphate buffer, growth occurred over the entire range of pH and was maximal at pH 5.5, but on media containing citrate–phosphate buffer, growth was maximal at pH 4.5, with little growth above pH 6.5. Dry matter accumulation was greatest at pH 4.5 and least at pH 7.5 in mineral salts broth buffered with phosphate or citrate–phosphate buffer. The water potential of media buffered with citrate–phosphate buffer was lower than that of media buffered with phosphate buffer, but these differences only partially explain the observed growth responses. Growth of C. gramineum occurred from 5 to 25 °C, but it was fastest at 20 °C. In general, temperature did not influence the qualitative response of C. gramineum to pH. The pH range most favorable to growth in vitro corresponds to the range of soil pH most favorable to development of cephalosporium stripe disease in the field and greenhouse; this may help explain the increased incidence of disease through increased inoculum potential.


1985 ◽  
Vol 65 (2) ◽  
pp. 269-282 ◽  
Author(s):  
J. L. DIONNE ◽  
A. R. PESANT

Alfalfa (Medicago sativa L. ’Saranac’) was grown on Ste. Rosalie clay, Greensboro loam and St. Jude sand adjusted to about pH 5.0, 6.5 and 7.5 in a greenhouse experiment, to determine the changes in response of alfalfa to aluminum and manganese resulting from variations in soil pH and soil moisture. Rates of Mn were equivalent to 0 and 200 kg∙ha−1 and rates of Al were 0, and 100 kg∙ha−1. Three soil moisture regimes were used: (1) Optimum with soil moisture between field capacity (FC) and 70% of this value. (2) Wet: with soil moisture between saturation point (SP) and FC. (3) Very wet: with soil moisture between saturation point and a value half way between SP and FC. Manganese applied on acid soils (pH 5.2) under optimum soil moisture regimes decreased alfalfa yields by 3% only, compared to a 62% decrease in alfalfa yields by Mn applied on acid soils of the two high soil moisture regimes. This was due to a high level of Mn in alfalfa on the wet acid soils. A large quantity of aluminum was also found in alfalfa grown in acid soils along with a high concentration of "extractable" aluminum. This resulted in a 54% reduction of alfalfa yields. Content of Al and Mn in alfalfa top and in soils was decreased sharply by liming soils at pH of 6.5 or 7.5. On soils limed to a pH of about 7.0 alfalfa survived at high levels of Mn and Al such as frequently encountered in some acid and very wet soils. Key words: Soil Mn, soil Al, soil pH, soil moisture, alfalfa


Author(s):  
Donald J Brown ◽  
Lacy E. Rucker ◽  
Catherine Johnson ◽  
Shane Jones ◽  
Thomas K. Pauley

The Central Appalachian Spruce Restoration Initiative was formed to promote restoration of red spruce Picea rubens forests in Central Appalachia. One goal of the initiative is to increase availability and enhance quality of habitat for wildlife, including the threatened Cheat Mountain salamander Plethodon nettingi. The purpose of this research was to compare microhabitat characteristics between an occupied Cheat Mountain salamander site and early-stage spruce restoration sites, and between four occupied sites and proximal non-detection sites. We found that soil pH was higher and soil moisture was lower at spruce restoration sites compared to the occupied site, and that light intensity, sub-canopy air temperature, and ground-level air temperature were higher in spruce restoration prescriptions with reduced canopy cover. We found that soil moisture was higher at occupied sites compared to proximal non-detection sites, but soil pH was not significantly different. Our study suggests that Cheat Mountain salamanders are associated with low soil pH and high soil moisture, and thus spruce restoration could enhance habitat quality for this species in the long-term.


Author(s):  
N.A. Thomson

In a four year grazing trial with dairy cows the application of 5000 kg lime/ ha (applied in two applications of 2500 kg/ha in winter of the first two years) significantly increased annual pasture production in two of the four years and dairy production in one year. In three of the four years lime significantly increased pasture growth over summer/autumn with concurrent increases in milk production. In the last year of the trial lime had little effect on pasture growth but a relatively large increase in milkfat production resulted. A higher incidence of grass staggers was recorded on the limed farmlets in spring for each of the four years. In the second spring immediately following the second application of lime significant depressions in both pasture and plasma magnesium levels were recorded. By the third spring differences in plasma magnesium levels were negligible but small depressions in herbage magnesium resulting from lime continued to the end of the trial. Lime significantly raised soil pH, Ca and Mg levels but had no effect on either soil K or P. As pH levels of the unlimed paddocks were low (5.2-5.4) in each autumn and soil moisture levels were increased by liming, these factors may suggest possible causes for the seasonality of the pasture response to lime


HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 599E-600
Author(s):  
Regina P. Bracy ◽  
Richard L. Parish

Improved stand establishment of direct-seeded crops has usually involved seed treatment and/or seed covers. Planters have been evaluated for seed/plant spacing uniformity, singulation, furrow openers, and presswheel design; however, effects of presswheels and seed coverers on plant establishment have not been widely investigated. Five experiments were conducted in a fine sandy loam soil to determine effect of presswheels and seed coverers on emergence of direct-seeded cabbage and mustard. Seed were planted with Stanhay 870 seeder equipped with one of four presswheels and seed coverers. Presswheels included smooth, mesh, concave split, and flat split types. Seed coverers included standard drag, light drag, paired knives, and no coverer. Soil moisture at planting ranged from 8% to 19% in the top 5 cm of bed. Differences in plant counts taken 2 weeks after planting were minimal with any presswheel or seed coverer. Visual observation indicated the seed furrow was more completely closed with the knife coverer in high soil moisture conditions. All tests received at least 14 mm of precipitation within 6 days from planting, which may account for lack of differences in plant emergence.


2020 ◽  
Vol 3 (1) ◽  
pp. 58
Author(s):  
Rachele Venanzi ◽  
Loredana Barbona ◽  
Francesco Latterini ◽  
Rodolfo Picchio

The aim of this work was to assess the possible impacts on the forest soil and stand due to silvicultural treatment and forest operations in a beech high forest. Even aged beech forests (Fagus sylvatica L.) in the Municipality of Cappadocia (L’Aquila) and in the Municipality of Vallepietra (Roma) were analyzed. The analysis of the soil and stand were performed in order to assess the effects attributable to applied silviculture and forest logging. Two different logging methodologies (in particular for the extraction) were applied: mules were used in the areas with greater slopes and with obstacles, while for the areas with better accessibility, mechanical means were used, in this case tractors. In detail, the main objective was to assess the disturbance on the ground and on the stand, generated by the two different levels of mechanization. In addition, it was also interesting to understand the possible effect on the soil and specifically on the partial uncovering where part of the tree canopy was removed. Only through an accurate cross-analysis of the studied parameters and indices could the anthropogenic impacts on the soil and stand due to forest operations be highlighted according to the different logging methodologies applied. The main results showed that the disturbances caused to the soil and stand were essentially caused in the bunching and extraction operations. The importance of avoiding or limiting the continuous passage of vehicles and animals on forest soil clearly emerges, especially in conditions of high soil moisture. It is also important to use correct technologies that are adequate for the specific environmental characteristics and the work plan. Finally, it can be said that there was no difference in the disturbance caused by the two logging methods when compared. Substantial differences in terms of improvement can be defined when comparing the findings of this study with other research studies. This can be done by applying a different type of mechanization with a different logging system.


Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 381
Author(s):  
J. Julio Camarero ◽  
Cristina Valeriano ◽  
Antonio Gazol ◽  
Michele Colangelo ◽  
Raúl Sánchez-Salguero

Background and Objectives—Coexisting tree and shrub species will have to withstand more arid conditions as temperatures keep rising in the Mediterranean Basin. However, we still lack reliable assessments on how climate and drought affect the radial growth of tree and shrub species at intra- and interannual time scales under semi-arid Mediterranean conditions. Materials and Methods—We investigated the growth responses to climate of four co-occurring gymnosperms inhabiting semi-arid Mediterranean sites in northeastern Spain: two tree species (Aleppo pine, Pinus halepensis Mill.; Spanish juniper, Juniperus thurifera L.) and two shrubs (Phoenicean juniper, Juniperus phoenicea L.; Ephedra nebrodensis Tineo ex Guss.). First, we quantified the intra-annual radial-growth rates of the four species by periodically sampling wood samples during one growing season. Second, we quantified the climate–growth relationships at an interannual scale at two sites with different soil water availability by using dendrochronology. Third, we simulated growth responses to temperature and soil moisture using the forward, process-based Vaganov‒Shashkin (VS-Lite) growth model to disentangle the main climatic drivers of growth. Results—The growth of all species peaked in spring to early summer (May–June). The pine and junipers grew after the dry summer, i.e., they showed a bimodal growth pattern. Prior wet winter conditions leading to high soil moisture before cambium reactivation in spring enhanced the growth of P. halepensis at dry sites, whereas the growth of both junipers and Ephedra depended more on high spring–summer soil moisture. The VS-Lite model identified these different influences of soil moisture on growth in tree and shrub species. Conclusions—Our approach (i) revealed contrasting growth dynamics of co-existing tree and shrub species under semi-arid Mediterranean conditions and (ii) provided novel insights on different responses as a function of growth habits in similar drought-prone regions.


1951 ◽  
Vol 4 (3) ◽  
pp. 211
Author(s):  
GC Wade

The disease known as white root rot affects raspberries, and to a less extent loganberries, in Victoria. The causal organism is a white, sterile fungus that has not been identified. The disease is favoured by dry soil conditions and high soil temperatures. It spreads externally to the host by means of undifferentiated rhizomorphs; and requires a food base for the establishment of infection. The spread of rhizomorphs through the soil is hindered by high soil moisture content and consequent poor aeration of the soil.


2015 ◽  
Vol 50 (7) ◽  
pp. 562-570 ◽  
Author(s):  
Marcela Tonini Venturini ◽  
Vanderlei da Silva Santos ◽  
Eder Jorge de Oliveira

Abstract: The objective of this work was to define procedures to assess the tolerance of cassava genotypes to postharvest physiological deterioration (PPD) and to microbial deterioration (MD). Roots of six cassava genotypes were evaluated in two experiments, during storage under different environmental conditions: high temperature and low soil moisture; or low temperature and high soil moisture. Roots were treated or not with fungicide (carbendazim) before storage. Genotype reactions to MD and PPD were evaluated at 0, 2, 5, 10, 15, 20, and 30 days after harvest (DAH), in the proximal, medial, and distal parts of the roots. A diagrammatic scale was proposed to evaluate nonperipheral symptoms of PPD. Fungicide treatment and root position did not influence PPD expression; however, all factors had significant effect on MD severity. Genotypes differed as to their tolerance to PPD and MD. Both deterioration types were more pronounced during periods of higher humidity and lower temperatures. The fungicide treatment increased root shelf life by reducing MD severity up to 10 DAH. Whole roots showed low MD severity and high PPD expression up to 10 DAH, which enabled the assessment of PPD without significant interference of MD symptoms during this period.


Sign in / Sign up

Export Citation Format

Share Document