Differential LongSAGE tag abundance analysis in a barley seed germination time course and validation with relative real-time RT-PCR

AbstractBoth temperature (T) and water potential (ψ) have consistent and quantifiable effects on the rate and extent of seed germination (radicle emergence). Germination at suboptimal T can be characterized on the basis of thermal time, or the T in excess of a base (Tb) multiplied by the time to a given percentage germination (tg). Similarly, germination at reduced ψ can be characterized on a hydrotime basis, or the ψ in excess of a base (ψb) multiplied by tg. Within a seed population, the variation in thermal times to germination for a specific percentage (g) is based upon the normal distribution of ψb values among seeds (ψb(g)). Germination responses across a range of suboptimal T and ψ might be accounted for by a general hydrothermal time model incorporating both T and ψ components. We tested this hypothesis for tomato (Lycopersicon esculentum Mill.) seeds of two genotypes differing in germination rates and tolerance of suboptimal T and ψ. For combinations of T (10−25°C) and ψ (0 to −0.9 MPa), a general hydrothermal time model accounted for approximately 75% of the variation in times to germination within the seed populations of both genotypes, and over 96% of the variation in median germination rates. However, ψb(g) distributions were sensitive to both the T and ψ of imbibition, resulting in a poor fit of the model to specific time course data. Analysis of germination timing separately for low and high ψ ranges within a given T resulted in specific models accounting for 88−99% of the variation in individual germination times and >99% of the variation in madian germination rates. Thus, for a given T and ψ range, the hydrotime model closely matched tomato seed germination time courses. Accumulated hydrothermal time accounted well for germination rates at ψ> −0.5 MPa across suboptimal T if ψb(g) was allowed to vary with T. Germination did not show a consistent response to T at ψ < −0.5 MPa, and estimated Tb values varied over different T ranges. Generalization of the hydrothermal time model across the entire range of suboptimal T and ψ was limited by physiological adjustments of the seeds to their current environment. The hydrothermal time model detected and quantified these adjustment processes that would otherwise not be evident from inspection of germination time courses. Temperature and water potential influence the time to germination via physiological mechanisms that reciprocally interact.

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Seed germination time course and seedling development ofClintonia udensisTrautv. et Mey. (Uvulariaceae): a typical cool temperate woodland perennial in Japan

Plant Species Biology ◽

10.1111/j.1442-1984.2012.00382.x ◽

2012 ◽

Vol 28 (3) ◽

pp. 235-242 ◽

Cited By ~ 1

Author(s):

KOJIRO SUZUKI ◽

NAHO IWASAKI ◽

HITOMI KAWANO ◽

SHOICHI KAWANO

Keyword(s):

Seed Germination ◽

Time Course ◽

Seedling Development ◽

Germination Time ◽

Cool Temperate

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Menangle virus, a pteropid bat paramyxovirus infectious for pigs and humans, exhibits tropism for secondary lymphoid organs and intestinal epithelium in weaned pigs

Journal of General Virology ◽

10.1099/vir.0.038448-0 ◽

2012 ◽

Vol 93 (5) ◽

pp. 1007-1016 ◽

Cited By ~ 13

Author(s):

Timothy R. Bowden ◽

John Bingham ◽

Jennifer A. Harper ◽

David B. Boyle

Keyword(s):

Real Time ◽

Intestinal Epithelium ◽

Neutralizing Antibodies ◽

Time Course ◽

Lymphoid Organs ◽

Lymphoid Tissues ◽

Rt Pcr ◽

Weaned Pigs ◽

Reproductive Disease ◽

Secondary Lymphoid Organs

This study is the first report of experimental infection and transmission of Menangle virus (MenPV) in pigs. Isolated in 1997 from piglets that were stillborn at a large commercial piggery in New South Wales, Australia, MenPV is a recently identified paramyxovirus of bat origin that causes severe reproductive disease in pigs and an influenza-like illness, with a rash, in humans. Although successfully eradicated from the infected piggery, the virus was only isolated from affected fetuses and stillborn piglets during the period of reproductive disease, and thus the mode of transmission between pigs was not established. To investigate the pathogenesis of MenPV, we undertook time-course studies in 6-week-old pigs following intranasal administration of a low-passage, non-plaque-purified isolate from the lung of an infected stillborn piglet. Viraemia was of short duration and low titre, as determined by real-time RT-PCR and virus isolation. Following an incubation period of 2–3 days, virus was shed in nasal and oral secretions, faeces and urine, typically for less than 1 week. Cessation of shedding correlated with the development of neutralizing antibodies in sera. Secondary lymphoid organs and intestine were identified, using quantitative real-time RT-PCR, as major sites of viral replication and dissemination, and this was confirmed by positive immunolabelling of viral antigen within various lymphoid tissues and intestinal epithelium. These data provide new insights into the pathogenesis of MenPV in weaned pigs, and will facilitate future control and eradication programmes should it ever re-emerge in the pig population.

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A hydrothermal time model of seed after-ripening in Bromus tectorum L.

Seed Science Research ◽

10.1017/s0960258500003214 ◽

1996 ◽

Vol 6 (4) ◽

pp. 155-164 ◽

Cited By ~ 66

Author(s):

Maren Christensen ◽

Susan E. Meyer ◽

Phil S. Allen

Keyword(s):

Seed Germination ◽

Water Potential ◽

Time Course ◽

Bromus Tectorum ◽

Incubation Temperature ◽

Hydrothermal Time ◽

Germination Time ◽

Water Potentials ◽

Incubation Temperatures ◽

Base Water Potential

AbstractBromus tectorum L. is an invasive winter annual grass with seeds that lose dormancy through the process of dry after-ripening. This paper proposes a model for after-ripening of B. tectorum seeds based on the concept of hydrothermal time. Seed germination time course curves are modelled using five parameters: a hydrothermal time constant, the fraction of viable seeds in the population, base temperature, mean base water potential and the standard deviation of base water potentials in the population. It is considered that only mean base water potential varies as a function of storage duration and incubation temperature following after-ripening. All other parameters are held constant throughout after-ripening and at all incubation temperatures. Data for model development are from seed germination studies carried out at four water potentials (0, −0.5, −1.0 and −1.5 MPa) at each of two constant incubation temperatures (15 and 25°C) following different storage intervals including recently harvested, partially after-ripened (stored for 4, 9 or 16 weeks at 20°C) and fully after-ripened (stored for 14 weeks at 40°C). The model was fitted using a repeated probit regression method, and for the two seed populations studied gave R2 values of 0.898 and 0.829. Germination time course curves predicted by the model generally had a good fit when compared with observed curves at the incubation temperature/water potential treatment combinations for different after-ripening intervals. Changes in germination time course curves during after-ripening of B. tectorum can largely be explained by decreases in the mean base water potential. The simplicity and good fit of the model give it considerable potential for extension to simulation of after-ripening under field conditions.

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