chaffy-seeded grasses can be debearded, i.e., removal of the hairs and awn (Ahring et al., 1964) or processed to Drought is the most frequent cause of stand establishment failure remove all appendages leaving only caryopses (Beisel, of native grasses. An experiment was conducted to determine the interactions of seed processing and simulated dry conditions on seed 1985). When conditions are favo...

A strip of paper placed on a hand spontaneously curls upwards. This simple observation illustrates the ability of a relatively homogeneous hygroscopic structural material, paper, to sense and respond to the microclimate near a non-equilibrium system, a moist evaporative boundary layer. We quantify this interaction using a simple experiment and show that it can be understood in terms of a minima...

Freshwater sponges in the Great Lakes St. Lawrence River system overgrow and kill introduced zebra (Dreissena pulymorpkza) and quagga mussels (DreisLse?aa bugerasis) on solid substrates. Sponges overgrow and smother mussel siphons, thereby interfering with normal feeding and respiration. We tested the significance of sponge-enhanced mussel mortality by repeated sampling at several sites where b...

the whole oat that is recovered as groat after dehulling. Groat percentage has long been recognized as an imporThe grain yield and quality determine much of the value of an oat tant indicator of oat quality (Love et al., 1925; Stoa et (Avena sativa L.) crop to the producer. This study investigated effects al., 1936; Atkins, 1943; Bartley and Weiss, 1951). Peek of genotype and environment on gra...

‘Medark’ rice (Oryza sativaL.) (Reg.No.CV-123, PI 636725) is a high-yielding, early maturing, semidwarf, medium-grain cultivar developed by the Arkansas Agricultural Experiment Station in cooperation with the USDA-ARS, the Louisiana State University Agricultural Center, the Mississippi Agricultural and Forestry Experiment Station, and the Texas Agricultural Experiment Station. It was released i...

Immature detached cereal caryopses from barley (Hordeum vulgare L. var distichum cv Midas) and wheat (Triticum aestivum L. cv Sicco) were shown to be capable of fixing externally supplied"'CO2 in the light or dark. Green cross cells and the testa contained the majority of the 14Clabeled material. Some "4C-labeled material was also found in the outer, or transparent, layer and in the endosperm/e...

Field and laboratory studies were carried out to test factors expected to be relevant for the germination of fountain grass: (1) light; (2) emergence of fountain grass seedlings from depths of 0, 2.5, and 5 cm; (3) fire passing over exposed and buried seeds; (4) laboratory heat treatment mimicking exposure to grass fire. Both fire in the field and heat applied in the laboratory killed fountain ...

The declining health of high-elevation red spruce (Picea ruhens Sarg.) and Fraser lir (Abies fraseri (Pursh) Poir.) in the southern Appalachian region has long been linked to nitrogen (N) deposition. Recently. N deposition has also been proposed as a source of negative health impacts in lower elevation deciduous forests. In 1998 we established 46 plotc on six sites in North Carolina and Virgini...

mained effective in North America longer than 5 yr after the resistance genes were released in pure-line Integrating selection for agronomic performance and quantitative cultivars (Holland, 1997). Monogenic resistances can be resistance to crown rust, caused by Puccinia coronata Corda var. avenae W.P. Fraser & Ledingham, in oat (Avena sativa L.) requires overcome rapidly by new races of the pat...