A field test of the directed deterrence hypothesis in two species of wild chili

Abstract  The directed deterrence hypothesis posits that secondary metabolites in ripe fruit function to deter fruit consumption by vertebrates that do not disperse seeds, while not impacting consumption by those that do. We tested this hypothesis in two species of wild chilies (Capsicum spp.). Both produce fruits that contain capsaicinoids, the compounds responsible for the pungency of chilies. Previous work suggests seed-dispersing birds but not seed-destroying rodents consume chili fruits, presumably because rodents are deterred by capsaicin. However, fruit removal from chili plants by rodents and other mammals has not been previously explored. Because laboratory rodents can develop a preference for capsaicin, it is quite possible that wild rodents are natural consumers of chili fruits. We monitored the fate of 125 marked fruits of Capsicum chacoense and 291 fruits of Capsicum annuum. For both species, essentially all fruit removal occurred during the day, when rodents are inactive. Video monitoring revealed fruit removal only by birds, mostly by species known to disperse chili seeds in viable condition. Furthermore, these species are from taxonomic groups that tend to specialize on lipid-rich fruits. Both species of chili produce fruits that are unusually high in lipids (35% in C. chacoense, 24% in C. annuum). These results support the directed deterrence hypothesis and suggest that fruiting plants distinguish between seed predators and seed dispersers by producing fruits that repel the former and attract the latter.

A Fatou–Bieberbach domain in \mathbb C2\mathbb {C}^2 which is not Runge

Abstract  Since a paper by Rosay and Rudin (Trans. Am. Math. Soc. 310, 47–86, 1988) there has been an open question whether all Fatou–Bieberbach domains are Runge. We give an example of a Fatou–Bieberbach domain Ω in which is not Runge. The domain Ω provides (yet) a negative answer to a problem of Bremermann.

A Fatou theorem for α-harmonic functions in Lipschitz domains

Abstract.  We study α-harmonic functions in Lipschitz domains. We prove a Fatou theorem when the boundary function is bounded and Lp-H?lder continuous of order β with βp > 1.

A fat attack occurred in fat city

A Digital Image-Based Method for Computational Tissue Fate Mapping During Early Avian Morphogenesis

Abstract  The early stages of vertebrate development, encompassing gastrulation, segmentation, and caudal axis formation, presumably involve large (finite) morphogenetic deformations; however, there are few quantitative biomechanical data available for describing such large-scale or tissue-level deformations in the embryo. In this study, we present a new method for automated computational “tissue fate mapping,” by combining a recently developed high-resolution time-lapse digital microscopy system for whole-avian embryo imaging with particle image velocimetry (PIV), a well-established digital image correlation technique for measuring continuum deformations. Tissue fate mapping, as opposed to classical cell fate mapping or other cell tracking methods, is used to track the spatiotemporal trajectories of arbitrary (virtual) tissue material points in various layers of the embryo, which can then be used to calculate finite morphogenetic deformation or strain maps. To illustrate the method, we present representative tissue fate and strain mapping data for normal early-stage quail embryos. These data demonstrate, to our knowledge, for the first time, large tissue-level deformations that are shared between different germ layers in the embryo, suggesting a more global morphogenetic patterning mechanism than had been previously appreciated.

A differential scanning calorimetry study on the oxidation of C12-C18 saturated fatty acids and their esters

Abstract  The autoxidation of lauric, myristic, palmitic, and stearic acids, their ethyl esters, and palmitic and stearic triglycerides was investigated by means of the isothermal and nonisothermal differential scanning calorimetry methods under oxygen flow. The activation energies of oxidation of all investigated compounds were similar (106.0–134.3 kJ/mol) and did not depend on length of the carbon chain. Kinetic parameters of start of the oxidation were similar for each investigated fatty acid and ester. Esterification of carboxyl group did not interfere with the reaction rate. The study showed good agreement between isothermal and nonisothermal data.

A Developmental Pattern of Flowering in Colored Zantedeschia spp.: Effects of Bud Position and Gibberellin

Abstract  The restricted flowering of colored cultivars of Zantedeschia is a consequence of developmental constraints imposed by apical dominance of the primary bud on secondary buds in the tuber, and by the sympodial growth of individual shoots. GA3 enhances flowering in Zantedeschia by increasing the number of flowering shoots per tuber and inflorescences per shoot. The effects of gibberellin on the pattern of flowering and on the developmental fate of differentiated inflorescences along the tuber axis and individual shoot axes were studied in GA3 and Uniconazole-treated tubers. Inflorescence primordia and fully developed (emerged) floral stems produced during tuber storage and the plant growth period were recorded. Days to flowering, percent of flowering shoots and floral stem length decreased basipetally along the shoot and tuber axes. GA3 prolonged the flowering period and increased both the number of flowering shoots per tuber and the differentiated inflorescences per shoot. Activated buds were GA3 responsive regardless of meristem size or age. Uniconazole did not inhibit inflorescence differentiation but inhibited floral stem elongation. The results suggest that GA3 has a dual action in the flowering process: induction of inflorescence differentiation and promotion of floral stem elongation. The flowering pattern could be a result of a gradient in the distribution of endogenous factors involved in inflorescence differentiation (possibly GAs) and in floral stem growth. This gradient along the tuber and shoot axes is probably controlled by apical dominance of the primary bud.