Effects of water supply on gas exchange, carbon isotopic composition, and relative growth rate were compared among seedlings from three populations of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) grown in a controlled environment chamber. The three populations were chosen to represent high, moderate and low drought tolerance. There was no indication that drought tolerance was related to hig...

This study was designed to investigate whether thermotolerant roots exhibit respiratory acclimation to elevated temperatures. Root respiratory acclimation traits in response to increasing temperatures were compared between two Agrostis species contrasting in heat tolerance: thermal A. scabra and heat-sensitive A. stolonifera. Roots of both species were exposed to 17, 27, or 37 degrees C. Root R...

BACKGROUND Anti-G antibodies are rarely found since anti-D, in combination with anti-C, are difficult to discriminate from anti-G antibodies in routine testing. CASE REPORT A 22-year-old, gravida-3, para-1, woman with blood group A Rh D neg ccddee and known antibody anti-Jk(b), gave birth to her second child. While anti-Jk(b) could not be detected at birth, a new anti-C was found. Antibody sc...

(Seedling growth of fifteen Brazilian tropical tree species differing in successional status). Growth of seedlings of fifteen tropical tree species representative, at the adult stage, of different successional positions, was studied under field conditions. Seedlings were grown in three treatments: full sun (FS), artificial shade imposed by neutral screens (AS) and natural shade imposed by a clo...

Food utilization by the larvae of Toxorhynchites splendens (Wiedemann) was studied in the laboratory by offering larvae of Aedes aegypti Linnaeus, Anopheles stephensi (Liston), and Culex quinquefasciatus (Say). Quantitative analyses of data indicated that immature development was significantly faster with increase in food availability. The regression analysis showed that the degrees of the rela...

The rate of herbicide resistance evolution in plants depends on fitness traits endowed by alleles in both the presence and absence (resistance cost) of herbicide selection. The effect of two Lolium rigidum spontaneous homozygous target-site resistance-endowing mutations (Ile-1781-Leu, Asp-2078-Gly) on both ACCase activity and various plant growth traits have been investigated here. Relative gro...

Submergence stress can cause the death of grass plants. Identification of the association between molecular markers and submergence tolerance-related traits facilitates an efficient selection of the tolerant cultivars for commercial production. A global collection of 99 diverse perennial ryegrass (Lolium perenne L.) accessions was evaluated for submergence tolerance and analyzed with 109 simple...

Ecological theory predicts that fitness costs of herbicide resistance should lead to the reduced relative abundance of resistant populations upon the cessation of herbicide use. This greenhouse research investigated the potential fitness costs of two multiple herbicide resistant (MHR) wild oat (Avena fatua) populations, an economically important weed that affects cereal and pulse crop productio...

The methanolic extract of milk thistle, Silybium marianum L. (Asterales: Asteraceae), was investigated for its effects on the mortality, growth, feeding indices, enzymatic activity, and levels of non-enzymatic molecules of the small white butterfly, Pieris rapae L. (Lepidoptera: Pieridae), a pest of cruciferous plants. Feeding indices including approximate digestibility (AD), efficiency of conv...

PREMISE OF THE STUDY Trait differences can promote distinct survival and fecundity responses to environmental fluctuations. In a Sonoran Desert winter annual plant community, we have identified a tradeoff between relative growth rate (RGR) and water-use efficiency (WUE) that predicts interannual variation in reproductive success. Here we test the hypothesis that traits underlying RGR and WUE di...