Incompatibility on brassica stigmas is overcome by treating pollen with cycloheximide

Pollen of Brassica exhibited strong self-incompatibility. It did not germinate on, adhere to, or extend into the stigmatic tissues of the female parent plant. In contrast, pollen that had been treated with cycloheximide germinated on and penetrated into self-stigmas to the same degree as untreated pollen placed on crossstigmas (compatible). Germ tubes from cycloheximide-treated pollen did not continue growth through stylar tissues and therefore were unable to effect fertilization.     

The oceanic sink for anthropogenic CO2

Using inorganic carbon measurements from an international survey effort in the 1990s and a tracer-based separation technique, we estimate a global oceanic anthropogenic carbon dioxide (CO2) sink for the period from 1800 to 1994 of 118 +/- 19 petagrams of carbon. The oceanic sink accounts for approximately 48% of the total fossil-fuel and cement-manufacturing emissions, implying that the terrestrial biosphere was a net source of CO2 to the atmosphere of about 39 +/- 28 petagrams of carbon for this period. The current fraction of total anthropogenic CO2 emissions stored in the ocean appears to be about one-third of the long-term potential.     

Urban aerosol toxicity: the influence of particle size

The basic thesis developed herein is that particle size is an extremely important parameter to consider when assessing the potential toxicity of species present in urban aerosols, and that surface adsorption or condensation greatly promotes toxicity. In the majority of cases this means that particles that are less than 1 micro.m in size are of primary importance. Special significance is attached to the organic constitutents of aerosols. Many of these are known or potential carcinogens and most predominate in extremely small particles which become deposited almost exclusively in the lung.     

Climate and land change impacts on future managed wetland habitat: a case study from California’s Central Valley

Landscape Ecology - California’s Central Valley provides critical habitat for migratory waterbirds, yet only 10% of naturally occurring wetlands remain. Competition for limited water supplies...     

Population characteristics of feral cats admitted to seven trap-neuter-return programs in the United States

Internationally, large populations of feral cats constitute an important and controversial issue due to their impact on cat overpopulation, animal welfare, public health, and the environment, and to disagreement about what are the best methods for their control. Trap-neuter-return (TNR) programs are an increasingly popular alternative to mass euthanasia. The objective of this study was to determine the population characteristics of feral cats admitted to large-scale TNR programs from geographically diverse locations in the United States. Data from 103,643 feral cats admitted to TNR programs from 1993 to 2004 were evaluated. All groups reported more intact females (53.4%) than intact males (44.3%); only 2.3% of the cats were found to be previously sterilized. Overall, 15.9% of female cats were pregnant at the time of surgery. Pregnancy was highly seasonal and peaked between March and April for all of the groups. The average prenatal litter size was 4.1+/-0.1 fetuses per litter. Cryptorchidism was observed in 1.3% of male cats admitted for sterilization. A total of 0.4% of cats was euthanased because of the presence of debilitating conditions, and 0.4% died during the TNR clinics. Remarkably similar populations of cats with comparable seasonal variability were seen at each program, despite their wide geographical distribution. These results suggest that it is feasible to safely sterilize large numbers of feral cats and that the experiences of existing programs are a consistent source of information upon which to model new TNR programs.