Infrared Thermal Imaging as a Rapid Tool for Identifying Water‐Stress Tolerant Maize Genotypes of Different Phenology

The main task of this research was to evaluate canopy temperature and Crop Water Stress Index (CWSI) by assessing genotype variability of maize performance for different water regimes. To that end, three hundred tropical and subtropical maize hybrids with different phenology in terms of date of anthesis were evaluated. The influence of phenology on the change in canopy temperatures and CWSI was not equal during the three dates of measurement. At the end of vegetative growth (82 days after sowing, DAS) and at the blister stage (DAS 97), a high significant difference in temperatures and CWSI (P < 0.001) were obtained between the early‐ and late‐maturity genotypes. During anthesis (DAS 89), phenology had a significant effect (P < 0.01) only for the well‐watered genotypes, while under water‐stress conditions, no differences were found between early and late genotypes in terms of canopy temperature and CWSI. High significant differences (P < 0.001) in stomatal conductance (g_s) between early and late genotypes for different treatments were observed. A relationship (R² = 0.62) between g_s and canopy temperature was obtained. Under a water‐stress canopy, temperature was measured at anthesis, which was negatively correlated with grain yield of the early (r = ?0.55)‐ and late (r = ?0.46)‐maturity genotypes in the water‐stressed condition.     

Genetical control of alkaloid production in Lupinus mutabilis and the effect of a mutant allele Mutal isolated following chemical mutagenesis

Summary A new mutant allele, described here as mutal, which reduces the alkaloid content in dry matter of lupinus mutabilis has been identified following seed treatment with ethyl methane sulphanate. The allele, when homozygous, reduces the alkaloid content from levels of > 2.0 per cent found in seed dry matter of existing populations to 0.2–0.3 per cent and produces plants with vegetative and seed tissues that are organoleptically sweet. Component alkaloids in plants homozygous for mutal differ in respect of the percentage composition of sparteine and of lupanine, as well as possibly of oxa-sparteine and 4-hydroxylupanine, but none is eliminated in genotypes homozygous for the mutant allele. Alkaloid concentration, in so far as not under the control of mutal, has low heritability but lines were isolated following two generations of successive selection which possessed reduced alkaloid levels. These were interpreted to have arisen as a result of recombination of alleles affecting reduction in alkaloid level at several loci. the mutant, mutal, has been established in a pure breeding line which represents a crucial additional step in the evolution of Lupinus mutabilis towards full status as a crop plant.     

Effects of increasing acidity on aquatic protozoan communities

Laboratory tests were conducted to evaluate the chronic effects of increased acidity on protozoan communities. Taxonomic richness of the protozoan component of these communities was severely affected at pH ≤ 5.33. Taxonomic composition was significantly affected at much higher pH. A permissible concentration was defined as the pH affecting no more than 20% of the species and estimated from concentration-response regression as 6.92 (5.92 to 8.04) pH units. A similar value estimated from more conventional chronic toxicity tests was 6.28 (6.16 to 6.45) pH units. Bacterial abundance decreased at pH levels ≤ 5.34 pH units. Other nontaxonomic responses (e.g., biomass, algal biomass, fungal biomass, net oxygen metabolism) were not sensitive to increases in acidity.     

Hydrologic pathways and chemical composition of runoff during snowmelt in Loch Vale Watershed,Rocky Mountain National Park,Colorado, USA

Intensive sampling of a stream draining an alpine-subalpine basin revealed that depressions in pH and acid neutralizing capacity (ANC) of surface water at the beginning of the spring snowmelt in 1987 and 1988 were not accompanied by increases in strong acid anions, and that surface waters did not become acidic (ANC<0). Samples of meltwater collected at the base of the snowpack in 1987 were acidic and exhibited distinct ‘pulses’ of nitrate and sulfate. Solutions collected with lysimeters in forest soils adjacent to the stream revealed high levels of dissolved organic carbon (DOC) and total Al. Peaks in concentration of DOC, Al, and nutrient species in the stream samples indicate a flush of soil solution into the surface water at the beginning of the melt. Infiltration of meltwater into soils and spatial heterogeneity in the timing of melting across the basin prevented stream and lake waters from becoming acidic.     

Behavior development in the dog: an interspecific analysis

Young dogs were maintained in isolation from other dogs and under varying degrees of exposure to an alien species (mature rabbits). Parametric observations indicate that an interspecific social attachment develops during the initial hours of co-habitation. The later social interaction patterns of the dogs were influenced, but not irrevocably fixed, by the early cross-specific rearing experience.     

Design and chemical synthesis of a homogeneous polymer-modified erythropoiesis protein

We report the design and total chemical synthesis of "synthetic erythropoiesis protein" (SEP), a 51-kilodalton protein-polymer construct consisting of a 166-amino-acid polypeptide chain and two covalently attached, branched, and monodisperse polymer moieties that are negatively charged. The ability to control the chemistry allowed us to synthesize a macromolecule of precisely defined covalent structure. SEP was homogeneous as shown by high-resolution analytical techniques, with a mass of 50,825 +/-10 daltons by electrospray mass spectrometry, and with a pI of 5.0. In cell and animal assays for erythropoiesis, SEP displayed potent biological activity and had significantly prolonged duration of action in vivo. These chemical methods are a powerful tool in the rational design of protein constructs with potential therapeutic applications.