Inherited biotic protection in a Neotropical pioneer plant

Chelonanthus alatus is a bat-pollinated, pioneer Gentianaceae that clusters in patches where still-standing, dried-out stems are interspersed among live individuals. Flowers bear circum-floral nectaries (CFNs) that are attractive to ants, and seed dispersal is both barochorous and anemochorous. Although, in this study, live individuals never sheltered ant colonies, dried-out hollow stems - that can remain standing for 2 years - did. Workers from species nesting in dried-out stems as well as from ground-nesting species exploited the CFNs of live C. alatus individuals in the same patches during the daytime, but were absent at night (when bat pollination occurs) on 60.5% of the plants. By visiting the CFNs, the ants indirectly protect the flowers - but not the plant foliage - from herbivorous insects. We show that this protection is provided mostly by species nesting in dried-out stems, predominantly Pseudomyrmex gracilis. That dried-out stems remain standing for years and are regularly replaced results in an opportunistic, but stable association where colonies are sheltered by one generation of dead C. alatus while the live individuals nearby, belonging to the next generation, provide them with nectar; in turn, the ants protect their flowers from herbivores. We suggest that the investment in wood by C. alatus individuals permitting stillstanding, dried-out stems to shelter ant colonies constitutes an extended phenotype because foraging workers protect the flowers of live individuals in the same patch. Also, through this process these dried-out stems indirectly favor the reproduction (and so the fitness) of the next generation including both their own offspring and that of their siblings, alladding up to a potential case of inclusive fitness in plants

Plant dispersal across the tropical Atlantic by wind and sea currents

This review brings together evidence on the monophyly and ages of angiosperm lineages ranging across the tropical Atlantic with data on the direction, strength, and speed of sea currents and wind jets across that ocean. Mainly for pragmatic reasons (data availability), the focus is on genera, which introduces a rank-based constraint into the analysis. However, trans-Atlantic disjunctions at the genus level seemed more likely to be attributable to long-distance dispersal than those involving families or species; family-level disjunctions often may date back to the breakup of Africa and South America, and species-level disjunctions often may be anthropogenic. At least 110 genera (listed in this article) contain species on both sides of the tropical Atlantic. Molecular phylogenies and age estimates from molecular clocks are available for 11 disjunct genera, tribes, and species. Inferred directions and modes of dispersal can be related parsimoniously to water currents between Africa and South America and to exceptional westerly winds blowing from northeastern Brazil to northwest Africa. Based on diaspore morphology and inferred dispersal biology in the 110 genera, trans-Atlantic dispersal by water (in both directions) appears more common than dispersal by wind or on birds. Wind dispersal appears to have occurred in the direction from South America to West Africa but rarely in the opposite direction

Multifunctional Bracts in the Dove Tree Davidia involucrata (Nyssaceae:Cornales)

Although there has been much experimental work on floral traits that are under selection from mutualists and antagonists, selection by abiotic environmental factors on flowers has been largely ignored. Here we test whether pollen susceptibility to rain damage could have played a role in the evolution of the reproductive architecture of Davidia involucrata, an endemic in the mountains of western China. Flowers in this tree species lack a perianth and are arranged in capitula surrounded by large (up to 10 cm#5 cm) bracts that at anthesis turn from green to white, losing their photosynthetic capability. Flowers are nectarless, and pollen grains are presented on the recurved anther walls for 5–7 days. Flower visitors, and likely pollinators, were mainly pollen-collecting bees from the genera Apis, Xylocopa, Halictus, and Lasioglossum. Capitula with natural or white paper bracts attracted significantly more bees per hour than capitula that had their bracts removed or replaced by green paper. Experimental immersion of pollen grains in water resulted in rapid loss of viability, and capitula with bracts lost less pollen to rain than did capitula that had their bracts removed, suggesting that the bracts protect the pollen from rain damage as well as attracting pollinators

Las Gentianaceae: botánica, fitoquímica y actividad biológica

Este artículo es una revisión actualizada sobre los metabolitos secundarios de la familia de las Gentianaceae. Estas plantas se emplean en la medicina tradicional de numerosos países y presentan actividad biológica interesante. Después de haber detallado botánicamente esta familia de plantas, que ha sido y que sigue siendo muy estudiada, se recogen los estudios fitoquímicos sobre numerosas especies. Los metabolitos característicos son los xantonas, una clase de compuestos no muy difundidos en el mundo vegetal. Son característicos también derivados de los seco-iridoides, y algunos alcaloides.This paper is a review on the secondary metabolites of the Gentianaceae family. These plants are very well known as remedies in the traditional medicine of many countries because they present a number of biological activities. After a botanical presentation of this family, that is still studied, the phytochemical research of many species are reported. The most characteristic metabolites are xanthones, a class of natural products that is not very widespread in plants. Characteristic are also the seco-iridoids and alkaloids

Генетичний поліморфізм популяцій Gentiana lutea L. (gentianaceae) з Чорногірського масиву Українських Карпат

З використанням RAPD- та ISSR-ПЛР вивчено особливості генетичної структури та оцінено рівень мінливості популяцій G. lutea з гірського масиву Чорногора в Українських Карпатах. Встановлено високі показники рівня генетичної гетерогенності досліджених популяцій за цими ДНК-маркерами. На відмінності між популяціями припадає 59–72 % загальної генетичної мінливості, тоді як внутрішньопопуляційний поліморфізм становить 28–41 %. Припускається існування зв’язку між рівнем генетичної варіабельності та еколого-географічними умовами зростання виду і його біологічними особливостями. Отримані результати свідчать про генетичну ізоляцію чорногірських популяцій G. lutea в Українських Карпатах. Агропопуляція на горі Пожижевська характеризувалась високим рівнем поліморфізму, що свідчить про можливість використання штучних насаджень цього виду з метою його збереження.С использованием RAPD- и ISSR-ПЦР изучены особенности генетической структуры и оценен уровень изменчивости популяций G. lutea с Черногорского массива Украинских Карпат. Установлены высокие показатели уровня генетической гетерогенности исследованных популяций по этим ДНК-маркерам. Показано, что на различия между популяциями приходится 59–72 % общей генетической изменчивости, тогда как внутрипопуляционный полиморфизм составляет 28–41 %. Предполагается существование связи между уровнем генетической вариабельности и эколого-географическими условиями, а также биологическими особенностями вида. Полученные результаты свидетельствуют о генетической изоляции черногорских популяций G. lutea в Украинских Карпатах. Агропопуляция на горе Пожижевская характеризовалась высоким уровнем полиморфизма, что свидетельствует о возможности использования искусственных насаждений этого вида с целью его сохранения.Features of genetic structure and level of diversity of G. lutea populations from the Chornohora Ridge of the Ukrainian Carpathians were studied using RAPD- and ISSR-PCR. A high level of genetic diversity for studied populations concerning these DNA-markers is shown. The differences between populations are equal to 59–72% of the total genetic variation, whereas intrapopulation polymorphism makes up 28–41%. We assume that the relationships between genetic variability level and ecological-geographical conditions, as well as biological features of the species, are possible. The obtained results indicate the genetic isolation of G. lutea Chornohora populations from the Ukrainian Carpathians. Pozhyzhevska Mountain agropopulation was characterized by high level of polymorphism that means the possibility to use artificial plantings of this species for its preservation