Enhanced shoot investment makes invasive plants exhibit growth advantages in high nitrogen conditions

Resource amendments commonly promote plant invasions, raising concerns over the potential consequences of nitrogen (N) deposition; however, it is unclear whether invaders will benefit from N deposition more than natives. Growth is among the most fundamental inherent traits of plants and thus good invaders may have superior growth advantages in response to resource amendments. We compared the growth and allocation between invasive and native plants in different N regimes including controls (ambient N concentrations). We found that invasive plants always grew much larger than native plants in varying N conditions, regardless of growth- or phylogeny-based analyses, and that the former allocated more biomass to shoots than the latter. Although N addition enhanced the growth of invasive plants, this enhancement did not increase with increasing N addition. Across invasive and native species, changes in shoot biomass allocation were positively correlated with changes in whole-plant biomass; and the slope of this relationship was greater in invasive plants than native plants. These findings suggest that enhanced shoot investment makes invasive plants retain a growth advantage in high N conditions relative to natives, and also highlight that future N deposition may increase the risks of plant invasions.

The kinetics of hemopexin and alpha1-acid glycoprotein levels induced by injection of inflammatory agents in chickens

The acute phase response to inflammation induces changes in the secretion of hepatic proteins. To examine the time course of an acute phase protein response in broiler chickens, the plasma levels of hemopexin (HX) and alpha1-acid glycoprotein (AGP) and liver HX mRNA were measured at various time points from 3 hr to 336 hr after an intraabdominal injection of either lipopolysaccharide (LPS), complete Freund's adjuvant, incomplete Freund's adjuvant, phytohemagglutin, or mineral oil. Uninjected chicks served as controls. The accumulation of liver HX mRNA began within 3 hr of stimulation and peaked at 12 hr. Relative to control levels, plasma HX and AGP levels increased by 6-12 hr postchallenge and peaked at 24 hr. Complete Freund's adjuvant and LPS treatments induced the greatest increase in plasma HX (threefold; P < 0.05). Plasma levels of HX and AGP returned to control levels at 336 and 168 hr postinjection, respectively. A second experiment demonstrated that turpentine induced a similar AGP response as LPS and that albumin is a negative acute phase protein. The results suggest that plasma levels of HX or AGP could be used as an indicator of the systemic component of a local inflammatory response in chickens.

The three-consideration diet revisited

Three-consideration diets based on the 1974 Recommended Dietary Allowances, current food composition data, and October 1975 retail prices in Atlanta have been developed for a reference family of four persons. While the diets are less than satisfactory as to variety and palatability, they have a greater degree of variety than three-consideration diets published in earlier decades.