Maternal effects on early juvenile traits in Iris pumila (Iridaceae)

The variation in the maternal effects on a number of the early Iris pumila seedling traits expressed under high and low light levels in a growthroom was studied. A reciprocal crossing design was used for the establishment of 20 full-sib families. Each family consisted of two maternal groups differing only in genotype used as a seed parent. Maternal variation was estimated from the variance between maternal groups within sibships. Two parameters for maternal variation were computed: the maternal effects coefficient m(2) and the coefficient of maternal variation CVM. Maternal effects significantly accounted for the phenotypic variation in seed mass and most of the early seedling traits. Light conditions prevailing during the seedling development markedly influenced overall structure of maternal correlations. Implications of maternal correlations on the integration of juvenile phenotype have also been discussed.nul

Maternal effects on early juvenile traits in Iris pumila (Iridaceae)

The variation in the maternal effects on a number of the early Iris pumila seedling traits expressed under high and low light levels in a growthroom was studied. A reciprocal crossing design was used for the establishment of 20 full-sib families. Each family consisted of two maternal groups differing only in genotype used as a seed parent. Maternal variation was estimated from the variance between maternal groups within sibships. Two parameters for maternal variation were computed: the maternal effects coefficient m(2) and the coefficient of maternal variation CVM. Maternal effects significantly accounted for the phenotypic variation in seed mass and most of the early seedling traits. Light conditions prevailing during the seedling development markedly influenced overall structure of maternal correlations. Implications of maternal correlations on the integration of juvenile phenotype have also been discussed.nul

Reaction norms of juvenile traits to light intensity in Iris pumila (Iridaceae): a comparison of populations from exposed and shaded habitats

Reaction norms were determined in two natural populations of the perennial plant Iris pumila from contrasting light conditions at two levels of photosynthetically active radiation (105 and 35 mu mol m(-2)s(-1)). Seedlings developed from free-pollinated seed families sampled individually from 19 and 12 randomly selected clonal genotypes in an exposed and a shaded population respectively, were grown in a growth room using a mixed model nested factorial experimental design and scored for a number of phenological and morphological traits. Ambient light conditions significantly affected all of the juvenile traits measured. In both populations, relatively convergent norms of reactions were revealed for leaf appearance dates, as well as for leaf number, suggesting the importance of these traits for functional adjustment to prevailing light conditions. Reaction norms for morphological traits, however, were largely nonparallel, but although often crossing each other, a significant family-by-treatment interaction in the ANCOVAs performed was not detected for any of the traits measured, indicating a small amount of genetic variation for plasticity in these populations. The extent of plastic response to light availability was determined and expressed as an index that estimates the percentage change in a trait value from a high to a low light level. Evolutionary and ecological implications of the observed plastic variations are also discussed.nul

Reaction norms of juvenile traits to light intensity in Iris pumila (Iridaceae): a comparison of populations from exposed and shaded habitats

Reaction norms were determined in two natural populations of the perennial plant Iris pumila from contrasting light conditions at two levels of photosynthetically active radiation (105 and 35 mu mol m(-2)s(-1)). Seedlings developed from free-pollinated seed families sampled individually from 19 and 12 randomly selected clonal genotypes in an exposed and a shaded population respectively, were grown in a growth room using a mixed model nested factorial experimental design and scored for a number of phenological and morphological traits. Ambient light conditions significantly affected all of the juvenile traits measured. In both populations, relatively convergent norms of reactions were revealed for leaf appearance dates, as well as for leaf number, suggesting the importance of these traits for functional adjustment to prevailing light conditions. Reaction norms for morphological traits, however, were largely nonparallel, but although often crossing each other, a significant family-by-treatment interaction in the ANCOVAs performed was not detected for any of the traits measured, indicating a small amount of genetic variation for plasticity in these populations. The extent of plastic response to light availability was determined and expressed as an index that estimates the percentage change in a trait value from a high to a low light level. Evolutionary and ecological implications of the observed plastic variations are also discussed.nul

Testing the adaptive plasticity of Iris pumila leaf traits to natural light conditions using phenotypic selection analysis

A multivariate selection analysis has been used to test the adaptiveness of several In's pumila leaf traits that display plasticity to natural light conditions. Siblings of a synthetic population comprising 31 families of two populations from contrasting light habitats were grown at an open dune site and in the understory of a Pinus nigra stand in order to score variation in phenotypic expression of six leaf traits: number of senescent leaves, number of live leaves, leaf length, leaf width, leaf angle, and specific leaf area. The ambient light conditions affected the values of all traits studied except for specific leaf area. In accordance to ecophysiological expectations for an adaptive response to light, both leaf length and width were significantly greater while the angle between sequential leaves was significantly smaller in the woodland understory than at the exposed dune site. The relationship between leaf traits and vegetative fitness (total leaf area) differed across light habitats as predicted by functional hypotheses. The standardized linear selection gradient (beta') for leaf length and width were positive in sign in both environments, but their magnitude for leaf length was higher in the shade than under full sunlight. Since plasticity of leaf length in the woodland shade has been recognized as adaptive, fitness cost of producing plastic change in leaf length was assessed. In both of the available methods used, the two-step and the multivariate regression procedures, a rather high negative association between the fitness value and the plasticity of leaf length was obtained, indicating a cost of plasticity. The selection gradient for leaf angle was weak and significant only in the woodland understory Genetic correlations between trait expressions in contrasting light environments were negative in sign and low in magnitude, implying a significant genetic variation for plasticity in these leaf traits. Furthermore, leaf length and leaf width were found to be genetically positively coupled, which indicates that there is a potential for these two traits to evolve toward their optimal phenotypic values even faster than would be expected if they were genetically independent. (C) Elsevier, Parisnul

Synthesis of thin films by the pyrosol process

Among many aerosol routes, the Pyrosol process, due to its simplicity, low cost and quality of obtained films, represents a promising technique for the synthesis of thin films. The pyrosol process is based on the transport and pyrolysls of an aerosol of processor solution, generated in an ultrasonic atomizer, on a heated substrate. The theoretical principles of the pyrosol process are presented in this paper, as well as the influence of some synthesis parameters on the deposition of SnO2 thin films