scholarly journals Effect of environmental and cultural conditions in medium pH and plant growth performance of Douglas-fir (Pseudotsuga menziesii) shoot culture

F1000Research ◽  
2014 ◽  
Vol 3 ◽  
pp. 298
Author(s):  
Chien-Chih Chen ◽  
Rick Bates ◽  
John Carlson

The medium pH level of plant tissue culture has been shown to be essential to many aspects of explant development and growth. Sensitivity or tolerance of medium pH changein vitrovaries accordingly to specific requirements of individual species. The objectives of this study are to 1) determine medium pH change over time in storage conditions and with presence of explants, 2) evaluate the effects of medium pH change and explant growth performance and 3) assess the effects of adding a pH stabilizer, 2-(N-morpholino)ethanesulfonic acid (MES) to Douglas-fir micropropagation medium. Spring buds, collected before breaking dormancy from juvenile and mature donor trees were utilized for these evaluations. Medium with or without MES, each at five medium pH levels was pre-adjusted before adding MES, agar and autoclaving. Medium pH changes and explant growth parameters were measured at eight different incubation times. In general, medium with MES provided a more stable medium pH compared to pre-adjusted pH values under two storage conditions as well as with presence of explants over time. A general trend of decreasing medium pH over time was found comparing explants from juvenile and mature donor genotypes. Explant height and weight growth increased over time, but differ among explants from juvenile and mature donor genotypes. MES may help to maintain stable medium pH for bulk medium preparation. Our findings suggested a 21-day subculture practice may facilitate to sustain medium freshness, medium pH level and desirable explant growth.

F1000Research ◽  
2015 ◽  
Vol 3 ◽  
pp. 298 ◽  
Author(s):  
Chien-Chih Chen ◽  
Rick Bates ◽  
John Carlson

The medium pH level of plant tissue cultures has been shown to be essential to many aspects of explant development and growth. Sensitivity or tolerance of medium pH changein vitrovaries according to specific requirements of individual species. The objectives of this study are to 1) determine medium pH change over time in storage conditions and with presence of explants, 2) evaluate the effects of medium pH change on explant growth performance and 3) assess the effects of adding a pH stabilizer, 2-(N-morpholino)ethanesulfonic acid (MES) that is commonly used in Douglas-fir micropropagation medium. Vegetative buds were collected in the spring before breaking dormancy from juvenile and mature donor trees for conducting these evaluations. Medium, with or without MES, was pre-adjusted to five pH levels before adding MES, agar and autoclaving. Medium pH changes and explant growth parameters were measured at eight different incubation times. Overall, MES provided a more stable medium pH, relative to starting pH values, under both light and dark storage conditions as well as with presence of explants. A general trend of decreasing medium pH over time was found comparing explants from juvenile and mature donor genotypes. Explant height and weight growth increased over time, but differ among explants from juvenile and mature donor genotypes. Our findings suggest that a 21-day subculture practice may best sustain medium freshness, medium pH level and desirable explant growth.


2017 ◽  
Vol 95 (1) ◽  
pp. 194 ◽  
Author(s):  
P. J. Kononoff ◽  
P. J. Defoor ◽  
M. J. Engler ◽  
R. S. Swingle ◽  
J. F. Gleghorn ◽  
...  

2019 ◽  
Author(s):  
Buddhika Dorakumbura ◽  
Francesco Busetti ◽  
Simon Lewis

<p>Transformation of squalene and its by-products in fingermarks over time under different storage conditions (light, dark and underwater) was examined through ultrahigh-pressure liquid chromatography high resolution accurate mass Orbitrap™ mass spectrometry. Complications of assessing fingermark compositional variation over time using multiple samples with varying initial compositions were elucidated and a more rational approach was successfully demonstrated. Squalene was detected in all fresh natural fingermarks and the amount ranged between 0.20 to 11.32 μg/5 fingertips. A notable difference in the transformation of squalene was observed with different storage conditions, where a dark aquatic environment accelerated degradation of squalene compared to dark but dry conditions. Squalene monohydroperoxide was extremely short-lived in natural deposits while the amount of squalene epoxide was still increasing relative to the initial amount, after ageing under dark and aquatic conditions for up to 7 days. Some oxidation by-products of cholesterol were also tentatively identified, which exhibited a growth over time against their initial concentration under any of the storage condition tested. These by-products, therefore, show potential as biomarkers for targeted visualisation of aged deposits.</p>


2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 54-55
Author(s):  
Leigh Ruckman ◽  
Stacie Gould ◽  
John Patience

Abstract Mycotoxins may not be an issue every year, but the proper environmental conditions can cause a spike in contaminated grains and cause severe economic impact on pork producers. The objective of this study was to determine the effect of naturally occurring infections of deoxynivalenol, zearalenone and fumonisins (DZF) on growth performance and carcass parameters in grow/finish pigs. One hundred pigs (BW 34.0 ± 0.9 kg; L337 × Camborough, PIC, Hendersonville, TN) were randomly assigned to 1 of 2 dietary treatments with 10 split-sex pens/treatment. The control diet (CTL) contained low levels of DZF and the CTL+DFZ diet contained high levels of DZF. Diets were fed in 4 phases over the 126-d experiment period. The CTL diet contained 1.6, 1.6, 1.8 and 1.2 mg deoxynivalenol/kg and CTL+DZF contained 9.2, 6.9, 5.8 and 3.8 mg deoxynivalenol/kg in the 4 diet phases, respectively. The CTL contained 0.30, 0.32, 0.51 and 0.32 mg zearalenone/kg and 0.7, 0.8, 0.8 and 0.9 mg total fumonisins/kg; CTL+DFZ contained 0.59, 0.72, 0.86 and 0.57 mg zearalenone/kg and 1.0, 1.1, 1.2 and 0.9 mg total fumonisins/kg for phases one through four, respectively. Data were analyzed using PROC MIXED of SAS (9.4) with treatment, sex, and their interaction as fixed effects. Compared to CTL, feeding CTL+DFZ decreased final BW (130.3 vs 120.5 kg; P&lt; 0.001), ADG (0.95 vs 0.79 kg/d; P&lt; 0.001), ADFI (2.73 vs 2.49 kg/d; P=0.016), and G:F (0.35 vs 0.32; P=0.043). Feeding CTL+DFZ decreased HCW (92.3 vs 89.4 kg; P=0.024) and increased dressing percentage (70.9 vs 74.3%; P=0.009) and tended to reduce loin depth (7.0 vs 6.8 cm; P=0.057) compared to CTL. Diet did not affect backfat depth or lean percentage (P &gt;0.10). In conclusion, diets naturally contaminated with multiple mycotoxins reduced growth performance and adversely affected carcass parameters; pigs did not adapt over time to the mycotoxins.


Author(s):  
Dong Suk Han ◽  
Kawsher M. D. Solayman ◽  
Ho Kyong Shon ◽  
Ahmed Abdel-Wahab

AbstractThis study investigated the Hg(II) removal efficiencies of the reactive adsorbent membrane (RAM) hybrid filtration process, a removal process that produces stable final residuals. The reaction mechanism between Hg(II) and pyrite and the rejection of the solids over time were characterized with respect to flux decline, pH change, and Hg and Fe concentration in permeate water. Effects of the presence of anions (Cl−, SO42−, NO3−) or humic acid (HA) on the rejection of the Hg(II)-contacted pyrite were studied. The presence of both HA and Hg(II) increased the rate of flux decline due to the formation of irreversible gel-like compact cake layers as shown in the experimental data and modeling related to the flux decline and the SEM images. Stability experiments of the final residuals retained on the membrane using a thiosulfate solution (Na2S2O3) show that the Hg(II)-laden solids were very stable due to little or no detection of Hg(II) in the permeate water. Experiment on the possibility of continuously removing Hg(II) by reusing the Hg/pyrite-laden membrane shows that almost all Hg(II) was adsorbed onto the pyrite surface regardless of the presence of salts or HA, and the Hg(II)-contacted pyrite residuals were completely rejected by the DE/UF system. Therefore, a membrane filter containing pyrite-Hg(II) could provide another reactive cake layer capable of further removal of Hg(II) without post-chemical treatment for reuse.


2009 ◽  
Vol 75 (23) ◽  
pp. 7409-7416 ◽  
Author(s):  
Ana Cláudia N. F. Spinelli ◽  
Anderson S. Sant'Ana ◽  
Salatir Rodrigues-Junior ◽  
Pilar R. Massaguer

ABSTRACT The prevention of spoilage by Alicyclobacillus acidoterrestris is a current challenge for fruit juice and beverage industries worldwide due to the bacterium's acidothermophilic growth capability, heat resistance, and spoilage potential. This study examined the effect of storage temperature on A. acidoterrestris growth in hot-filled orange juice. The evolution of the A. acidoterrestris population was monitored under six different storage conditions after pasteurization (at 92°C for 10 s), maintenance at 85°C for 150 s, and cooling with water spray to 35°C in about 30 min and using two inoculum levels: <101 and 101 spores/ml. Final cooling and storage conditions were as follows: treatment 1, 30°C for the bottle cold point and storage at 35°C; treatment 2, 30°C for 48 h and storage at 35°C; treatment 3, 25°C for the bottle cold point and storage at 35°C; treatment 4, 25°C for 48 h and storage at 35°C; treatment 5, storage at 20°C (control); and treatment 6, filling and storage at 25°C. It was found that only in treatment 5 did the population remain inhibited during the 6 months of orange juice shelf life. By examining treatments 1 to 4, it was observed that A. acidoterrestris predicted growth parameters were significantly influenced (P < 0.05) either by inoculum level or cooling and storage conditions. The time required to reach a 104 CFU/ml population of A. acidoterrestris was considered to be an adequate parameter to indicate orange juice spoilage by A. acidoterrestris. Therefore, hot-filled orange juice should be stored at or below 20°C to avoid spoilage by this microorganism. This procedure can be considered a safe and inexpensive alternative to other treatments proposed earlier.


2011 ◽  
Vol 26 (4) ◽  
pp. 317-327 ◽  
Author(s):  
Valentín D. Picasso ◽  
E. Charles Brummer ◽  
Matt Liebman ◽  
Philip M. Dixon ◽  
Brian J. Wilsey

AbstractCropping systems that rely on renewable energy and resources and are based on ecological principles could be more stable and productive into the future than current monoculture systems with serious unintended environmental consequences such as soil erosion and water pollution. In nonagricultural systems, communities with higher species diversity have higher productivity and provide other ecosystem services. However, communities of well-adapted crop species selected for biomass production may respond differently to increasing diversity. Diversity effects may be due to complementarity among species (complementary resource use and facilitative interactions) or positive selection effects (e.g., species with higher productivity dominate the mixture), and these effects may change over time or across environments. Our goal was to identify the ecological mechanisms causing diversity effects in a biodiversity experiment using agriculturally relevant species, and evaluate the implications for the design of sustainable cropping systems. We seeded seven perennial forage species in a replicated field experiment at two locations in Iowa, USA, and evaluated biomass productivity of monocultures and two- to six-species mixtures over 3 years after the establishment year under management systems of contrasting intensity: one or three harvests per year. Productivity increased with seeded species richness in all environments, and the positive relationship did not change over time. Polyculture overyielding was due to complementarity among species in the community rather than to selection effects of individual species. Complementarity increased as a log-linear function of species richness in all environments, and this trend was consistent across years. Legume–grass facilitation may explain much of this complementarity effect. Although individual species with high biomass production had a major effect on productivity of mixtures, the species producing the highest biomass in monoculture changed over the years in most environments. Furthermore, transgressive overyielding was observed and was more prevalent in later years, in some environments. We conclude that choosing a single well-adapted species for maximizing productivity may not be the best alternative over the long term and that high levels of species diversity should be included in the design of productive and ecologically sound agricultural systems.


2004 ◽  
Vol 22 (4) ◽  
pp. 690-695 ◽  
Author(s):  
Marcos G. Cunha ◽  
David M. Rizzo

A new potato tuber disease has been observed in the Tulelake region, California, USA, since 1995, with tuber symptoms suggestive of silver scurf disease (Helminthosporium solani). In this work we isolated, identified and demonstrated the nature of the causal agent of this potato disease in California. In addition, the distribution of H. solani in potato fields and the inoculum potential at harvest time were investigated. Disease progress and H. solani spore populations were also characterised under commercial storage conditions. The main fungal genera associated with potato tubers in storage were Helminthosporium solani, Colletotrichum sp., Fusarium sp., and Rhizoctonia sp. The results of Koch's postulates indicated that H. solani is responsible for the outbreak of silver scurf in the Tulelake region. In a disease survey in three commercial potato fields naturally infested, H. solani infections occurred in all fields. However, the extension of the infections differed significantly between the fields. During potato storage, silver scurf usually increased over time. The percentage of the tuber surface covered by silver scurf varied from 3.5% up to 35.5% during the storage period. The number of H. solani lesions per tuber also progressively increased from 6% up to 35%, six months after storage. H. solani spore populations also increased over time in all studied potato stores; nevertheless, they followed no consistent pattern, exhibiting multiple and variable peaks of increase and reduction during the period of storage.


2018 ◽  
Vol 48 (2) ◽  
pp. 70
Author(s):  
J. C. PAPATSAS (I.K. ΠΑΠΑΤΣΑΣ) ◽  
S. C. KYRIAKIS (Σ.Κ. ΚΥΡΙΑΚΗΣ) ◽  
O. PAPADOPOULOS (ΠΑΠΑΔΟΠΟΥΛΟΣ Ο.) ◽  
K. SARRIS (Κ. ΣΑΡΡΗΣ) ◽  
S. LEKKAS (Σ. ΛΕΚΚΑΣ)

In this trial study, the effect of the vaccination of growing/fattening pigs against Aujeszky's disease virus (ADV) was investigated, in a farm placed in an endemic to ADV area. Three different trial groups of 11-week old growing pigs were vaccinated either once or twice or left unvaccinated. Comparisons between groups were made with respect to growth parameters, carcass quality, as well as pathological and bacteriological findings. All vaccinated animals had significantly better growth performance and carcass quality in comparison to the unvaccinated group, while no significant differences were observed between once and twice vaccinated animals. Lower lungs' affection due to secondary pathogens was also observed in vaccinated groups when compared with the control group of pigs. Bacteriological examination revealed that the frequency of secondary pulmonary bacterial infections, such as Streptococcus suis and Pasteurella multocida was lower in vaccinated pigs compared to controls. It was concluded that single and probably double vaccination against ADV may improve growth performance and carcas quality and may reduce lung affection due to certain secondary pathogens, under the management conditions of the trial farm.


2020 ◽  
Author(s):  
Michael Joy ◽  
KJ Foote ◽  
P McNie ◽  
M Piria

© 2019 CSIRO. The number of New Zealand's freshwater fish listed as threatened has increased since 1992 when the first New Zealand threat classification system list was compiled. In this study, temporal and land cover-related trends were analysed for data on freshwater fish distribution, comprising more than 20 000 records for the 47 years from January 1970 to January 2017 from the New Zealand Freshwater Fish Database. The analysis included individual species abundance and distribution trends, as well as an index of fish community integrity, namely the Index of Biotic Integrity (IBI). Of the 25 fish species that met the requirements for analysis to determine changes in the proportion of sites they occupied over time, 76% had negative trends (indicating declining occurrence). Of the 20 native species analysed for the proportion of sites occupied over time, 75% had negative trends; 65% of these were significant declines and more species were in decline at pasture sites than natural cover sites. The average IBI score also declined over the time period and, when analysed separately, the major land cover types revealed that the IBI declined at pasture catchment sites but not at sites with natural vegetation catchments.


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