Extreme plastomes in holoparasitic Balanophoraceae are not the norm.

Background: Balanophoraceae plastomes are known for their highly condensed and re-arranged nature alongside the most extreme nucleotide compositional bias known to date, culminating in two independent reconfigurations of their genetic code. Currently, a large portion of the Balanophoraceae diversity remains unexplored, hindering, among others, evolutionary pattern recognition. Here, we explored newly sequenced plastomes of Sarcophyte sanguinea and Thonningia sanguinea.

Structural Plastome Evolution in Holoparasitic Hydnoraceae with Special Focus on Inverted and Direct Repeats.

Plastome condensation during adaptation to a heterotrophic lifestyle is generally well understood and lineage-independent models have been derived. However, understanding the evolutionary trajectories of comparatively old heterotrophic lineages that are on the cusp of a minimal plastome, is essential to complement and expand current knowledge. We study Hydnoraceae, one of the oldest and least investigated parasitic angiosperm lineages.

Homoploid hybrids, allopolyploids, and high ploidy levels characterize the evolutionary history of a western North American quillwort (Isoëtes) complex.

Polyploidy and hybridization are important processes in seed-free plant evolution. However, a major gap lies in our understanding of how these processes affect the evolutionary history of high-ploidy systems. The heterosporous lycophyte genus Isoëtes is a lineage with many putative hybrids and high-level polyploid taxa (ranging from tetraploid to dodecaploid).

Detecting and Characterizing the Highly Divergent Plastid Genome of the Nonphotosynthetic Parasitic Plant Hydnora visseri (Hydnoraceae).

Plastid genomes of photosynthetic flowering plants are usually highly conserved in both structure and gene content. However, the plastomes of parasitic and mycoheterotrophic plants may be released from selective constraint due to the reduction or loss of photosynthetic ability. Here we present the greatly reduced and highly divergent, yet functional, plastome of the nonphotosynthetic holoparasite Hydnora visseri (Hydnoraceae, Piperales).

Major trends in stem anatomy and growth forms in the perianth-bearing Piperales, with special focus on Aristolochia.

Background And Aims: The order Piperales has the highest diversity of growth forms among the earliest angiosperm lineages, including trees, shrubs, climbers and herbs. However, within the perianth-bearing Piperales (Asarum, Saruma, Lactoris, Hydnora, Prosopanche, Thottea and Aristolochia), climbing species only occur in the most species-rich genus Aristolochia. This study traces anatomical and morphological traits among these lineages, to detect trends in growth form evolution and developmental processes.

Single-copy nuclear genes place haustorial Hydnoraceae within piperales and reveal a cretaceous origin of multiple parasitic angiosperm lineages.

Extreme haustorial parasites have long captured the interest of naturalists and scientists with their greatly reduced and highly specialized morphology. Along with the reduction or loss of photosynthesis, the plastid genome often decays as photosynthetic genes are released from selective constraint. This makes it challenging to use traditional plastid genes for parasitic plant phylogenetics, and has driven the search for alternative phylogenetic and molecular evolutionary markers.

Nutritional and isotopic relationships of selected Bornean tropical mistletoe-host associations in Brunei Darussalam.

Our understanding of mineral nutrition and carbon heterotrophy in mistletoes is derived largely from arid and temperate plant communities. Sharp differences between the tropical, temperate and arid communities, such as seasonality, water availability and mean temperature may influence basic assumptions regarding mistletoe physiology. Thus, we present mineral nutrition profiles and natural abundance carbon and nitrogen stable isotope data for tropical mistletoes and their hosts.

Isotopic evidence of partial mycoheterotrophy in the Gentianaceae: Bartonia virginica and Obolaria virginica as case studies.

Premise Of The Study: An estimated 10% of plant species have evolved to steal C from their symbiotic fungal partners (mycoheterotrophy), and while physiological evidence for full and partial mycoheterotrophy is well developed in the Orchidaceae and Ericaceae, it is lacking for the majority of other mycoheterotrophic taxa. The family Gentianaceae not only contains several lineages of achlorophyllous mycoheterotrophs, but also contains species that are putative partially mycoheterotrophic. The North American genera Bartonia and Obolaria (Gentianaceae) are green but have leaves reduced to scales or foliose bracts and so have ambiguous mycoheterotrophic status.

Floral thermogenesis of three species of Hydnora (Hydnoraceae) in Africa.

Background And Aims: Floral thermogenesis occurs in at least 12 families of ancient seed plants. Some species show very high rates of respiration through the alternative pathway, and some are thermoregulatory, with increasing respiration at decreasing ambient temperature. This study assesses the intensity and regulation of respiration in three species of African Hydnora that represent the Hydnoraceae, an unusual family of holoparasitic plants from arid environments.

Structural attributes of the hypogeous holoparasite Hydnora triceps Drege & Meyer (Hydnoraceae).

The morphology of the hypogeous root holoparasite Hydnora triceps is highly reduced, and as with many holoparasites, the vegetative body is difficult to interpret. The vegetative body of H. triceps has been historically considered a "pilot root" studded with lateral appendages known as "haustorial roots.