Holoparasitic Rafflesiaceae possess the most reduced endophytes and yet give rise to the world’s largest flowers
Species in the parasitic plant family Rafflesiaceae exhibit one of the most highly modified vegetative bodies in flowering plants. Apart from the flower shoot and associated bracts, the parasite is a mycelium-like endophyte living inside their grapevine hosts. This study provides a comprehensive treatment of the endophytic vegetative body for all three genera of Rafflesiaceae (Rafflesia, Rhizanthes and Sapria), and reports on the cytology and development of the endophyte, including its structural connection to the host, shedding light on the poorly understood nature of this symbiosis.
Plant traits and ecosystem effects of clonality: a new research agenda
Clonal plants spread laterally by spacers between their ramets (shoot–root units); these spacers can transport and store resources. While much is known about how clonality promotes plant fitness, we know little about how different clonal plants influence ecosystem functions related to carbon, nutrient and water cycling. This review gives some concrete pointers as to how to implement this new research agenda through a combination of (1) standardized screening of predominant species in ecosystems for clonal response traits and for effect traits related to carbon, nutrient and water cycling; (2) analysing the overlap between variation in these response traits and effect traits across species; (3) linking spatial and temporal patterns of clonal species in the field to those for soil properties related to carbon, nutrient and water stocks and dynamics; and (4) studying the effects of biotic interactions and feedbacks between resource heterogeneity and clonality. Linking these to environmental changes may help us to better understand and predict the role of clonal plants in modulating impacts of climate change and human activities on ecosystem functions.
Selenium addition alters mercury uptake, bioavailability in the rhizosphere and root anatomy of rice
Mercury is an extremely toxic pollutant, especially in the form of methylmercury, whereas selenium is an essential trace element in the human diet. This study aimed to ascertain whether addition of selenium can produce rice with enriched selenium and lowered mercury content when growing in mercury-contaminated paddy fields and, if so, to determine the possible mechanisms behind these effects.
Patch size and distance: modelling habitat structure from the perspective of clonal growth
In a patchy habitat, parents and their offspring can be under different environmental conditions, for example in terms of light/shade or high/low nutrient concentration. This study considers the spatial structure of patchy habitats from the perspective of plants that forage for resources by clonal growth. Modelling is used in order to compare two basic strategies, which differ in the response of the plant to a patch boundary. The results suggest that the degree of physiological integration between a parent and an offspring ramet is important even across a very short distance because it can strongly influence the efficiency of foraging.
Variable response of three white clover ecotypes to soil flooding by seawater
Despite concerns about the impact of rising sea levels and storm surge events on coastal ecosystems, there is remarkably little information on the response of terrestrial coastal plant species to seawater inundation. This study examines the responses of a glycophyte (white clover, Trifolium repens) to short-duration soil flooding by seawater and recovery following leaching of salts and suggests that selection for tolerant ecotypes is possible should the predicted increase in frequency of storm surge flooding events occur.
Changes in tracheid and ray traits in fire scars of North American conifers and their ecophysiological implications
Fire scars have been widely used as proxies for the reconstruction of fire history. However, little is known about the impact of fire injury on wood anatomy. This study investigates changes in tracheid and ray traits in fire scars of Douglas fir (Pseudotsuga menziesii), western larch (Larix occidentalis) and ponderosa pine (Pinus ponderosa), and discusses their ecophysiological implications for tree recovery from fire.
Morphological and physiological divergences within holm oak support the existence of different ecotypes depending on climatic dryness
Previous studies show contradictory findings about the functional convergence within the Mediterranean woody flora. This study evaluates the variability of functional traits within holm oak (Quercus ilex) to elucidate whether provenances corresponding to different morphotypes represent different ecotypes locally adapted to the prevaling stress levels. This is the first time that the combined use of morphological and physiological traits has provided support for the concept of these two holm oak morphotypes being regarded as two different species.