Field‐grown Cotton Exhibits Seasonal Variation in Photosynthetic Heat Tolerance without Exposure to Heat‐stress or Water‐deficit Conditions          下载免费PDF全文

J. L. Snider  D. R. Chastain  G. D. Collins 《Journal of Agronomy and Crop Science》2015,201(4):312-320

Thermotolerance acclimation of photosystem II to heat and drought is well documented, but studies demonstrating developmental impacts on heat tolerance in field‐grown plants are limited. Consequently, climatic variables, estimated canopy temperature, predawn leaf water potential (Ψ_PD), and the temperature responses of maximum quantum yield of photosystem II (F_v/F_m), variable fluorescence (F_v/F₀), quantum yield of electron transport (φ_Eο) and efficiency of PSI electron acceptor reduction (REο/ABS) were characterized for Gossypium hirsutum at three sample times during the growing season (21 June, 2 July and 18 July 2013) under well‐watered conditions. The temperature decreasing a given photosynthetic parameter 15% from the optimum is referred to as T₁₅ and served as a standardized measure of heat tolerance. Ambient and estimated canopy temperatures were well within the optimal range for cotton throughout the sample period, and leaves were verified well watered using Ψ_PD measurements. However, T₁₅ varied with sample date (highest on July 2 for all parameters), being 2 °C (F_v/F₀) to 5.5 °C (φ_Eο) higher on July 2 relative to June 21, despite optimal temperature conditions and predawn leaf water potential on all sample dates. These findings suggest that even under optimum temperature conditions and water availability, heat tolerance could be influenced by plant developmental stage.  相似文献   

Pericardial effusion from granulomatous pleuritis and pericarditis in a dog     

C B Chastain  J H Greve  D H Riedesel 《Journal of the American Veterinary Medical Association》1974,164(12):1201-1202

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Fracture of the apex of the patella after medial patellar desmotomy in a horse     

CB RILEY  JV YOVICH 《Australian veterinary journal》1991,68(1):37-39

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Therapeutic compliance     

CB CHAPMAN 《Australian veterinary journal》1996,74(6):442-442

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Intensive care of dogs and cats with diabetic ketoacidosis     

C B Chastain 《Journal of the American Veterinary Medical Association》1981,179(10):972-978

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A possible predisposition to dilated cardiomyopathy in Huntaway dogs     

JS Munday  CB Dyer  AC Hartman  GMB Orbell 《New Zealand veterinary journal》2013,61(5):231-234

AIM: To compare the prevalence of dilated cardiomyopathy (DCM) in New Zealand Huntaway dogs with the prevalence of DCM in other breeds of dog.

METHODS: The necropsy database at Massey University was used to identify cases of DCM diagnosed between January 1999 and March 2006. Dogs were considered to have DCM if echocardiographic, gross necropsy, or histological findings were consistent with this diagnosis. The prevalence in Huntaways was then compared with the prevalence observed in all breeds of dog, as well as the prevalence observed in large breeds of dog.

RESULTS: Twelve dogs were identified with DCM. One was diagnosed using echocardiography, while the other 11 were diagnosed by gross necropsy examination. The gross diagnosis of DCM was confirmed histologically in 6/11 dogs. The prevalence of DCM in Huntaways was significantly higher than the prevalence seen in all breeds of dog (p=0.008), and the prevalence in large breeds of dog (p=0.025). All four Huntaways diagnosed with DCM were male, and had an average age of 4 years. Three dogs presented with symptoms attributable to impaired heart function while one presented with symptoms of chronic renal failure. The duration of clinical symptoms prior to presentation ranged between 1 day and 3 weeks.

CONCLUSIONS: The results of this study suggest that Huntaways may be predisposed to the development of DCM. Although the increased prevalence in this breed was significant, only small numbers of affected Huntaways were identified, and additional cases are required to confirm these preliminary findings.

CLINICAL RELEVANCE: Huntaways are the most common working dog in New Zealand. The premature loss of a working dog is expected to have a significant economic impact on farmers. Further investigation of DCM in Huntaways may allow measures to reduce the prevalence in this breed.  相似文献   

Foliar Phosphorus Applications in the Forms of Phosphate and Phosphite Have Contrasting Effects on Wheat Performance Under Field Conditions     

Zambrosi  Fernando CB 《Journal of Crop Science and Biotechnology》2019,22(5):395-401

Journal of Crop Science and Biotechnology - Since phosphite (Phi) cannot replace phosphate (Pi) as source of phosphorus (P) for plants, and grain crops might experience P deficiency after anthesis,...  相似文献   

Electron Transport Through Photosystem II Is Not Limited By A Wide Range of Water Deficit Conditions In Field‐Grown Gossypium hirsutum     

J. L. Snider  G. D. Collins  J. Whitaker  C. D. Perry  D. R. Chastain 《Journal of Agronomy and Crop Science》2014,200(1):77-82

Despite exhaustive literature describing drought stress effects on photosynthesis in Gossypium hirsutum, the sensitivity of photosynthetic electron flow to water deficit is heavily debated. To address this, G. hirsutum plants were grown at a field site near Camilla, GA under contrasting irrigation regimes, and pre‐dawn water potential (Ψ_PD), stomatal conductance (g_s), net photosynthesis (P_N), actual quantum yield of photosystem II (Φ_PSII) and electron transport rate (ETR) were measured at multiple times during the 2012 growing season. Ψ_PD values ranged from ?0.3 to ?1.1 MPa. Stomatal conductance exhibited a strong (r² = 0.697), sigmoidal response to Ψ_PD, where g_s was ≤0.1 mol m^?2 s^?1 at Ψ_PD values ≤ ?0.86 MPa. Neither Φ_PSII (r² = 0.015) nor ETR (r² = 0.010) was affected by Ψ_PD, despite exceptionally low Ψ_PD values (?1.1 MPa) causing a 71.7 % decline in P_N relative to values predicted for well‐watered G. hirsutum leaves at Ψ_PD = ?0.3 MPa. Further, P_N was strongly influenced by g_s, whereas ETR and Φ_PSII were not. We conclude that photosynthetic electron flow through photosystem II is insensitive to water deficit in field‐grown G. hirsutum.  相似文献   

A pilot study to investigate the measurement of immunoglobulin A in Welsh Cob and Welsh Pony foals’ faeces and their dam’s milk     

CB Riley  CJ Jenvey  FJ Baker  A Corripio 《New Zealand veterinary journal》2020,68(4):225-230

ABSTRACT

Aims: To determine if an ELISA for measurement of IgA in equine serum could be used to measure concentrations of IgA in foal faeces and to determine correlations with concentrations in the milk of the dam.

Methods: Faeces from 20 Welsh Cob and Welsh Pony foals and milk from their dams were collected within 12?hours (Day 0) and at 6 days after parturition (Day 6). On Day 6, faeces could not be collected from 2/20 foals, and milk samples could not be collected from 3/20 mares. An equine IgA ELISA validated for serum and plasma was used to measure concentrations of IgA in all samples in triplicate. The precision of the assay for each sample type was determined using modified CV.

Results: IgA was not detectable in 7/20 Day 0 faecal samples and in 2/18 Day 6 faecal samples. For samples with detectable IgA, the mean modified CV was 10.5 (95% CI?=?6.0–15.0)% for Day 0 faecal samples, and was 6.8 (95% CI?=?4.3–9.4)% for Day 6 faecal samples. Median concentrations of IgA in faeces on Day 0 were lower than concentrations on Day 6 (0.7?mg/g vs. 37?mg/g dry matter; p?=?0.003). Concentrations of IgA in milk and faeces on Day 6 were statistically correlated (r?=?0.59; p?=?0.006).

Conclusions and clinical relevance: The IgA ELISA showed acceptable precision when used to estimate concentrations of IgA in foal faeces during the first week of life, but IgA could not be detected in 37% of meconium samples collected on Day 0. This assay may be useful for investigation of the role of maternal milk IgA in the gastrointestinal tract of neonatal foals, but further assessment of both accuracy and precision of the ELISA is required.  相似文献   

Larvicidal activity of natural and modified triterpenoids against Aedes aegypti (Diptera: Culicidae)          下载免费PDF全文

Gloria NS da Silva  Frances TT Trindade  Francine dos Santos  Grace Gosmann  Alexandre A e Silva  Simone CB Gnoatto 《Pest management science》2016,72(10):1883-1887

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