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In this paper, we analyze the perfective progressive periphrasis (PPP) in Brazilian Portuguese (BrP) and Argentinian Spanish (AS) in a comparative way. Based on different linguistic tests, we make two statements regarding the PPP in comparison with the imperfective progressive periphrasis (IPP). Firstly, we claim that the PPP has a progressive and perfective meaning. Secondly, we claim that the PPP allows iterative readings when combined with telic events (i.e., achievements in BrP and AS and accomplishments just in AS). We propose a syntactic and semantic analysis which accounts for these observations in a compositional way: while the gerund form expresses a progressive meaning (present in both periphrases), the auxiliary on the PPP expresses a perfective meaning which allows the iterative readings observed in this periphrasis. [ABSTRACT FROM AUTHOR]

BACKGROUND Glandular trichomes are essential in plants' defence against pests however, the mechanisms of action are not completely understood. While there is considerable evidence of feeding and movement impairment by trichomes, the effect on other traits is less clear. We combined laboratory and greenhouse experiments with molecular analysis to understand how glandular trichomes affect the behavior, population growth, and the expression of biomarkers involved in detoxification, primary metabolism, and developmental pathways of the aphid Macrosiphum euphorbiae. We used two isogenic tomato lines that differ in the presence of type IV glandular trichomes and production of acylsucroses; i.e.,Solanum lycopersicum cv. 'Moneymaker' and an introgressed line from Solanum pimpinellifolium (with trichomes type IV). RESULTS: Type IV glandular trichomes affected host selection and aphid proliferation with aphids avoiding, and showing impaired multiplication on the genotype with trichomes. The exposure to type IV glandular trichomes resulted in the overexpression of detoxication markers (i.e., Hsp70, Hsp17, Hsp10); the repression of the energetic metabolism (GAPDH), and the activation of the ecdysone pathway; all these, underlying the key adaptations and metabolic trade‐offs in aphids exposed to glandular trichomes. CONCLUSION: Our results demonstrate the detrimental effect of glandular trichomes (type IV) on the aphid and put forward their mode of action. Given the prevalence of glandular trichomes in wild and cultivated Solanaceae; and of the investigated molecular biomarkers in insects in general, our results provide relevant mechanisms to understand the effect of trichomes not only on herbivorous insects but also on other trophic levels. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Populations of heterostylous species are characterized by two or three floral morphs with reciprocal positioning of stigmas and anthers. Theoretical models predict equal morph frequencies (isoplethy) when disassortative mating is prevalent in populations, but biased morph ratios may occur when variation in the expression of heterostyly causes deviations from intermorph mating. M ETHODS: We explore the role of sex-organ deployment in governing morph ratios in two closely related genera of Boraginaceae, exhibiting striking variation in floral traits associated with the heterostylous syndrome. We sampled 66 populations of six species of Glandora and 39 populations of three species of Lithodora across their distributional range in the Mediterranean. In each population we estimated morph ratios and measured several floral traits. We used phylogenetically corrected and noncorrected regressions to test the hypothesis that differences in sex-organ reciprocity and herkogamy are associated with deviations from isoplethy. KEY RESULTS: Biased morph ratios occurred in 24% of populations, particularly in Lithodora. Populations biased for the long-styled morph (L-morph) were more frequent than the short-styled morph (S-morph). Distylous species were less likely to exhibit biased ratios than species with stigma-height dimorphism. In Lithodora fruticosa, a species lacking reciprocity, decreased herkogamy in the S-morph was associated with increasing L-morph bias, perhaps resulting from self-interference. C ONCLUSION: Striking variation in the expression of heterostyly in Glandora and Lithodora is associated with biased morph ratios, which probably result from pollinator-mediated mating asymmetries within populations. [ABSTRACT FROM AUTHOR]

Distylous species have two floral morphs with reciprocal positions of sexual whorls, functioning to promote cross-pollination. Additionally, most distylous species have an incompatibility system linked to the discrete variation of anthers and stigmas. Here we provide new data on heterostyly, reproductive biology and pollination in four Psychotria spp. from the Cerrado Region (Brazil). Psychotria deflexa, P. nitidula and P. trichophoroides fitted the distylous morphological syndrome, whereas P. prunifolia was monomorphic and self-compatible. Reciprocity varied across species, with the upper whorl of anthers and stigmas being more reciprocal than the lower whorl. Psychotria nitidula has a heteromorphic incompatibility system, whereas P. deflexa and P. trichophoroides showed partial self-compatibility. Psychotria prunifolia and P. trichophoroides were visited by large bees and exhibited lower reproductive efficacy than P. nitidula and P. deflexa, which are visited by wasps and small bees. Our results provide new evidence that the morphological distylous syndrome does not always co-occur with heteromorphic incompatibility and additional mechanisms (e.g. disassortative pollen transfer) may operate to maintain the polymorphism and isoplethy of species with different incompatibility system. [ABSTRACT FROM AUTHOR]

Heterostyly is a genetic polymorphism in which plant populations possess two (distyly) or three (tristyly) morphs with flowers differing reciprocally in stigma and anther height. Sex organ deployment has been described as being highly variable among and within species of several distylous taxa belonging to different taxonomic groups. However, the number of studies considering within-species disparities is still limited. For a better overview of the existing amount of variation that can occur within and between heterostylous species, we sampled 46 populations of six Melochia spp., a style-polymorphic genus in Cuba. We characterized the floral morphology in all populations and described a set of ancillary characters per species. All of these Melochia spp. are distylous, except for the monomorphic M. nodiflora. The S-morph produces fewer, larger pollen than L-morphs, and has verrucose ornamentation. The L-morph produces reticulate pollen and has larger stigmatic papillae than the S-morph. The monomorphic M. nodiflora shows ancillary characteristics that are similar to the L-morph individuals in the related species. As expected, there are differences in ancillary characters among species and also dissimilarities in reciprocity among and within species of Melochia. Our results highlight the importance of considering intraspecific variation in the morphometric characterization of heterostylous taxa. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176, 147-158. [ABSTRACT FROM AUTHOR]