Interspecific amphiploid‐derived alloplasmic male sterility with defective anthers,narrow disc florets and small ray flowers in sunflower     

Zhao Liu  Xiwen Cai  Gerald J. Seiler  Chao‐Chien Jan 《Plant Breeding》2014,133(6):742-747

The cytoplasmic male‐sterility (CMS)/fertility‐restoration system is important for hybrid sunflower (Helianthus annuus L.) seed production. The objective of this study was to characterize two novel alloplasmic CMSs, designated CMS GRO1 and CMS MAX3, with defective anthers, narrow disc florets with no swollen corolla, and short, narrow ray flowers derived from two tetraploid amphiploids (AMPs). Among 26 tested lines, only AMP Helianthus cusickii/P 21 and HA 410 failed to restore male‐fertility. Segregation of CMS, male‐fertile plants and plants with reduced male‐fertility was observed both in the testcross progeny of a six line half‐diallel cross of F₁s with CMS MAX3 and in an F₂ population of CMS GRO1 × RHA 274. Male‐fertility restoration was controlled by at least two dominant genes. Detailed analysis of the mitochondrial genes may provide insight into the differences between these CMSs and other CMS lines. The new CMSs will facilitate the studies of the incompatibility between cytoplasmic and nuclear genes, especially for the alloplasmic CMS involving perennial species, and also provide unique ornamental flower types and CMS sources for hybrid sunflower breeding.  相似文献   

Malignant fibrous histiocytoma involving the ilium in a cat     

R J Seiler  G T Wilkinson 《Veterinary pathology》1980,17(4):513-517

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A comparison of root growth dynamics of silver maple and flowering dogwood in compacted soil at differing soil water contents     

Day SD  Seiler JR  Persaud N 《Tree physiology》2000,20(4):257-263

Many bottomland tree species are tolerant of compacted soil and perform well in urban environments; however, the mechanism underlying this tolerance is unknown. Increased soil water content has been shown to alleviate some of the effects of soil compaction on plant growth, presumably because increasing soil water reduces soil strength. We hypothesized that tree species tolerant of very wet soils would have opportunities for root growth in compacted soil when high soil water contents reduced soil strength, whereas species intolerant of bottomland conditions would not. We tested this hypothesis on flowering dogwood (Cornus florida L.), a mesic species intolerant of inundation, and silver maple (Acer saccharinum L.), a bottomland species. Seedlings of both species were grown in pots for 21 and 30 days, respectively, in a growth chamber in native loam soil maintained at various combinations of soil strength and soil water tension. Downward root growth rate decreased in response to increasing soil strength in both species. At low soil strength (0.6 MPa), downward root growth rate of dogwood seedlings slowed when soil was either excessively wet or dry, whereas root growth rate of silver maple seedlings increased linearly with soil water content. In moderately compacted soil (1.5 g cm(-3) bulk density), silver maple seedlings had greater root growth rate, root length per plant, and ratio of root length to root dry weight in wet soil (0.006 MPa soil water tension) than in moist and dry soils (0.026 and 0.06 MPa, respectively), even though mean oxygen diffusion rate (ODR) was only 0.28 &mgr;g cm(-2) (SE = 0.05). No such effect was detected in highly compacted soil (1.7 g cm(-3) bulk density) in either species. Mean ODR showed a weak positive correlation with soil water tension (r = 0.40, P = 0.07), but was unrelated to soil strength. We conclude that silver maple roots can grow in moderately compacted soil when high soil water content decreases soil strength, whereas dogwood is unable to take advantage of this opportunity.  相似文献   

Tricuspid valve dysplasia in fifteen dogs     

Hoffmann G  Amberger CN  Seiler G  Lombard CW 《Schweizer Archiv für Tierheilkunde》2000,142(5):268-277

Clinical findings in fifteen dogs with tricuspid valve dysplasia are described. Thirteen dogs had loud systolic heart murmurs. Eleven of them hat a palpable precordial thrill over the same location. In 14 dogs, right heart enlargement was suspected on thoracic radiographs and electrocardiography. Right atrial dilation was seen echocardiographically in all dogs. Fourteen dogs had additional right ventricular dilatation, some with hypertrophy as well. Doppler echocardiography revealed tricuspid valve regurgitation. Seven dogs remained free of clinical symptoms to date. If symptoms of decompensation develop with tricuspid dysplasia, diuretics, ACE inhibitors and eventually positive inotrope drugs are indicated. Antiarrhythmic drugs may become necessary in cases of supraventricular tachyarrhythmias.  相似文献   

Growth, shoot phenology and physiology of diverse seed sources of black spruce: II. 23-year-old field trees     

Johnsen KH  Seiler JR  Major JE 《Tree physiology》1996,16(3):375-380

Four sources of 23-year-old black spruce (Picea mariana (Mill.) B.S.P.) from a provenance test at the Petawawa National Forestry Institute (46 degrees N, 77 degrees 30' W) were assessed for height growth, shoot phenology and seasonal gas exchange. The provenances were designated 7000 (Yukon, 63 degrees 34' N, 135 degrees 55' W), 6979 (Alberta 52 degrees 22' N, 115 degrees 15' W), 6908 (Ontario, 48 degrees 59' N, 80 degrees 38' W) and 6901 (Ontario, 45 degrees 10' N, 77 degrees 10' W). Trees of southern provenances (6901 and 6908) were considerably taller, and broke bud and ceased growth later than trees of northern provenances (6979 and 7000). In early spring, trees of northern provenances had higher net photosynthetic rates (P(n)) than trees of southern provenances (6908 and 6901). During midsummer, trees of Provenance 7000 generally had the highest P(n) as a result of low rates of shoot dark respiration (R(d)). Trees of northern provenances displayed an earlier autumn decline in P(n) than trees of southern provenances. Provenance differences in growth, shoot phenology and physiology agreed well with results from a greenhouse study of seedlings from the same provenances. We conclude that the poor growth performance of trees of northern provenances in Ontario was associated with: (1) a short period of shoot growth, (2) a high rate of dry matter partitioning to roots, (3) low rates of late-season P(n) in response to decreasing photoperiod, and possibly, (4) a high rate of root R(d).  相似文献   

Belowground carbon dynamics in loblolly pine (Pinus taeda) immediately following diammonium phosphate fertilization   总被引：2，自引：0，他引：2  

Gough CM  Seiler JR 《Tree physiology》2004,24(7):845-851

Forest soils store an immense quantity of labile carbon (C) and a may be a large potential sink for atmospheric C. Forest management practices such as fertilization may enhance overall C storage in soils, yet changes in physiological processes following nutrient amendments have not been widely investigated. We intensively monitored belowground C dynamics for nearly 200 days following diammonium phosphate fertilization of pot-grown loblolly pine (Pinus taeda L.) seedlings in an effort to examine the short-term effects of fertilization on processes involved in soil C sequestration. Soil respiration rates initially increased in fertilized pots relative to controls, followed by a brief reversal in this trend and then a final sustained pattern of elevated rates of soil respiration in the fertilized treatment. Patterns in soil respiration rates over time reflected changes in autotrophic (root) and heterotrophic (microbial) components of soil respiration. Root respiration rates were greater in the fertilized treatment 49 days following fertilization and returned to control rates by the end of the study. In contrast, microbial respiration rates and microbial activity per soil C concentration remained depressed over the same time period. Compared with control seedlings, total root biomass was 27% greater in fertilized seedlings harvested at the end of the study, indicating that the elevated soil respiration rates observed toward the end of the study were a result of increased respiring root biomass. We conclude that fertilization, at least over the short-term, may increase soil C sequestration by increasing belowground biomass production and reducing microbial driven C turnover.  相似文献   

Growth responses of six seed sources of Pinus brutia Ten. (Turkish red pine) to herbaceous weed competition     

Esen  Derya  Zedaker  Shepard M.  Seiler  John R.  Mou  Pu 《New Forests》2003,25(1):1-10

Herbaceous weeds present amajor obstacle to foresters in the earlyestablishment and growth of Turkish red pine (Pinus brutia Ten.), an important coniferof the semi-arid Mediterranean region. Greatgenetic variability of this pine species indrought resistance has already beenwell-studied. The existence of such variationwithin this species in relation to herbaceousweed competition is unknown. This studyinvestigated the effect of herbaceous weedcompetition on the growth of the seedlings ofTurkish red pine seed sources with differentmoisture regimes in their native sites, usingthe rapid screening technique. Two-month-oldTurkish red pine seedlings were grown inindividual pots in a glasshouse either with orwithout joint goose goat grass (Aegilopscylindrica L.). After two simulatedgrowing seasons, grass competitionsignificantly and progressively reduced pinegrowth. Although mean total pine biomass wasreduced by 71% due to weed competition,seedlings of different pine seed sourcesdisplayed significant differences in growthresponses to the weed treatments: dry site seedsource seedlings generally exhibitedsignificantly greater growth than moist siteseed source seedlings under weed competition. These results suggest that competition fromherbaceous weeds is an important factor inreducing the early growth of Turkish red pineseedlings, and that selection ofcompetition-tolerant seed sources can result insubstantial enhancement of the competitivestatus of this pine species against itsherbaceous competitors in early years.  相似文献   

Association of Gallbladder Mucocele Histologic Diagnosis with Selected Drug Use in Dogs: A Matched Case‐Control Study          下载免费PDF全文

J.L. Gookin  M.T. Correa  A. Peters  A. Malueg  K.G. Mathews  J. Cullen  G. Seiler 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(6):1464-1472

Background

The cause of gallbladder mucocele (GBM) formation in dogs currently is unknown. Many available drugs represent a newer generation of xenobiotics that may predispose dogs to GBM formation.

Objective

To determine if there is an association between the histologic diagnosis of GBM in dogs and administration of selected drugs.

Animals

Eighty‐one dogs with a histologic diagnosis of GBM and 162 breed, age, and admission date‐matched control dogs from a single referral institution.

Methods

Medical records of dogs with GBM and control dogs from 2001 to 2011 were reviewed. Owner verification of drug history was sought by a standard questionnaire. Reported use of heartworm, flea, and tick preventatives as well as nonsteroidal anti‐inflammatory drugs, analgesics, corticosteroids, or medications for treatment of osteoarthritis was recorded.

Results

Dogs with GBM were 2.2 times as likely to have had reported use of thyroxine (as a proxy for the diagnosis of hypothyroidism) as control dogs (95% confidence interval [CI], 0.949–5.051), 3.6 times as likely to have had reported treatment for Cushing''s disease (95% CI, 1.228–10.612), and 2.3 times as likely to have had reported use of products containing imidacloprid (95% CI, 1.094–4.723). Analysis of a data subset containing only Shetland sheepdogs (23 GBM and 46 control) indicated that Shetland sheepdogs with GBM formation were 9.3 times as likely to have had reported use of imidacloprid as were control Shetland sheepdogs (95% CI, 1.103–78.239).

Conclusions and Clinical Importance

This study provides evidence for an association between selected drug use and GBM formation in dogs. A larger epidemiologic study of Shetland sheepdogs with GBM formation and exposure to imidacloprid is warranted.  相似文献   

Identification of resistance to new virulent races of rust in sunflowers and validation of DNA markers in the gene pool     

Qi L  Gulya T  Seiler GJ  Hulke BS  Vick BA 《Phytopathology》2011,101(2):241-249

Sunflower rust, caused by Puccinia helianthi, is a prevalent disease in many countries throughout the world. The U.S. Department of Agriculture (USDA)-Agricultural Research Service, Sunflower Research Unit has released rust resistant breeding materials for several decades. However, constantly coevolving rust populations have formed new virulent races to which current hybrids have little resistance. The objectives of this study were to identify resistance to race 336, the predominant race in North America, and to race 777, the most virulent race currently known, and to validate molecular markers known to be linked to rust resistance genes in the sunflower gene pool. A total of 104 entries, including 66 released USDA inbred lines, 14 USDA interspecific germplasm lines, and 24 foreign germplasms, all developed specifically for rust resistance, were tested for their reaction to races 336 and 777. Only 13 of the 104 entries tested were resistant to both races, whereas another six were resistant only to race 336. The interspecific germplasm line, Rf ANN-1742, was resistant to both races and was identified as a new rust resistance source. A selection of 24 lines including 19 lines resistant to races 777 and/or 336 was screened with DNA markers linked to rust resistance genes R(1), R(2), R(4u), and R(5). The results indicated that the existing resistant lines are diverse in rust resistance genes. Durable genetic resistance through gene pyramiding will be effective for the control of rust.  相似文献   

Election of fellows     

Seiler G 《Science (New York, N.Y.)》1990,248(4955):612

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