Biology subjects

Schoenenberger, J.

Publications and source records attributed to Schoenenberger, J..

5 recordsLinked to original sources

bioRxiv2025

Humidity-driven shape morphing enhances fog harvesting in porous cactus spines

Cacti develop spines instead of conventional leaves, which often serve as mechanical defence against herbivores and protection from excess sunlight. However, some cactus species grow porous and flexible spines, suggesting fundamentally different functions. Here we demonstrate that the porous spines of Turbinicarpus alonsoi, a cactus native to central Mexico, function as hygro-morphing fog harvesters. We discovered that the spines are highly hygroscopic and straighten when exposed to fog, leading to increased fog water collection rates. Experiments and numerical simulations confirm that straightening is driven by swelling-induced pressure in the cell walls of the spine tissue. Swelling results from capillary imbibition of fog water and predominantly generates expansion in the transverse plane, which causes the pre-curved spines to straighten. Despite their porosity and hygroscopicity, the spines prevent direct absorption of fog water into the living cortex due to the presence of a suberin-rich tissue layer at the spine base that instead promotes surface runoff towards the roots. Our work suggests that hygro-morphing emerges from distinct structural, biochemical and geometric adaptations of cactus spines, and enables a fine modulation of the flow dynamics on the surface of spines. The increasing plant water supply from fog by shape morphing provides a potential advantage for survival in a hot, semi-arid region with frequent fog formation. Significance statementIn many arid regions of the world, fog is a critical source of fresh water. Plants display striking ways to harvest this fog water. For cacti with porous spines, it has long been assumed that they collect fog water directly by capillary imbibition. However, we demonstrate that, in Turbinicarpus alonsoi, water-impermeable tissue at the spine base prevents direct transport of water into the living cortex. Instead, a dual process increases fog water collection: the curved spines initially imbibe fog water, which causes them to swell and straighten, and a thin liquid film then forms on the spine and runs off along the plant surface down to the roots. Hygro-morphing spines therefore enhance the capacity of cacti to collect fog water.

plant biology↗

bioRxiv2022

Profile of a flower: How rates of morphological evolution drive floral diversification in Ericales

Premise of the StudyRecent studies of floral disparity in the asterid order Ericales have shown that flowers vary strongly among families and that disparity is unequally distributed between the three flower modules (perianth, androecium, gynoecium). However, it remains unknown whether these patterns are driven by heterogeneous rates of morphological evolution or other factors. MethodsHere, we compiled a dataset of 33 floral characters scored for 414 extant ericalean species sampled from 346 genera and all 22 families. We conducted ancestral state reconstructions using an equal rates Markov models for each trait. We used the rates estimated during the ancestral state reconstruction for comparing evolutionary rates between flower modules, creating a "rate profile" of ericalean flowers. Key ResultsThe androecium exhibits the highest evolutionary rates across most characters, whereas most perianth and gynoecium characters evolve slower. High and low rates of morphological evolution can result in high floral disparity in Ericales. Analyses of an angiosperm-wide floral dataset reveal that this pattern appears to be conserved across most major angiosperm clades. ConclusionsElevated rates of morphological evolution in the androecium of Ericales may explain the higher disparity reported for this floral module. We discuss the implications of heterogenous morphological rates of evolution among floral modules from a functional perspective. Comparing rates of morphological evolution through rate profiles proves to be a powerful tool in understanding floral evolution.

plant biology↗

bioRxiv2022

Integrating Fossil Flowers into the Angiosperm Phylogeny using a Total Evidence Approach

Fossil flowers are essential to infer past angiosperm evolutionary processes. The assignment of fossil flowers to extant clades has traditionally relied on morphological similarity and on apomorphies shared with extant taxa. The use of explicit phylogenetic analyses to establish their affinity has so far remained limited. In this study, we built a comprehensive framework to investigate the phylogenetic placement of 24 exceptionally preserved fossil flowers. For this, we assembled a new species-level dataset of 30 floral traits for 1201 extant species that were sampled to represent the stem and crown nodes of all angiosperm families. We explored multiple analytical approaches to integrate the fossils into the phylogeny, including different phylogenetic estimation methods, topological-constrained analyses, and a total evidence approach combining molecular and morphological data of extant and fossil species. Our results were widely consistent across approaches, with minor differences in the support of fossils at different phylogenetic positions. The placement of some fossils is in agreement with previously suggested relationships, but for others, a new placement is indicated. We also identified fossils that are well constrained within particular extant families, whereas others showed high phylogenetic uncertainty. Finally, we present recommendations for future total evidence analyses, regarding the selection of fossils and appropriate methodologies, and provide some perspectives on how to integrate fossils into the investigation of divergence times and the temporal evolution of morphological traits.

paleontology↗

bioRxiv2017

Novel Computed Tomography-based tools reliably quantify plant reproductive investment

The flower is a bisexual reproductive unit where both genders compete for resources. Counting pollen and ovules in flowers is essential to understand how much is invested in each gender. Classical methods to count very numerous pollen grains and ovules are inefficient when pollen grains are tightly aggregated, and when fertilization rates of ovules are unknown. We thus established novel, Computed-Tomography-based counting techniques. In order to display the potential of our methods in very difficult cases, we counted pollen and ovules across inflorescences of deceptive and rewarding species of European orchids, which possess both very large numbers of pollen grains (tightly aggregated) and ovules. Pollen counts did not significantly vary across inflorescences and pollination strategies, whereas deceptive flowers had significantly more ovules than rewarding flowers. The within inflorescence variance of pollen to ovule ratios in rewarding flowers was four times higher than in deceptive flowers, possibly demonstrating differences in the constraints acting on both pollination strategies. We demonstrate the inaccuracies and limitations of previously established methods, and the broad applicability of our new techniques: they allow measurement of reproductive investment without restriction on object number or aggregation, and without specimen destruction.

plant biology↗

bioRxiv2017

Response of oriental xerophytes to the occidental industrial revolution

Since the Industrial Revolution, human activities have contributed substantially to climate change, by adding CO2 to the atmosphere, especially since the mid-20th century (the \"Great Acceleration\"). Climatic change does not have the same impact on different regions of the Earth, neither in the recorded past, nor in models of the future. Therefore, to anticipate on these changes, we need to understand and be able to predict the possible responses of the different regional vegetations of the world to these changes, and most significantly to increased drought conditions. The aim of this study is to understand the response of the xerophytes of the immense oriental Irano-Turanian bioregion to post-industrial global warming and to compare it with the response of the xerophytes of the neighbouring occidental Mediterranean bioregion. We measured stomata index and stomata density from 83 herbarium sheets (coll. 1821-2014) from species of the non-succulent xerophyte, Haplophyllum. We tested for differences before and after the \"Great Acceleration\" in both bioregions. SI decreased in the occidental species (significant only for abaxial leaf side), whereas SI significantly increased in the oriental species (both sides). We suggest that changes in both occidental and oriental species are linked to atmospheric CO2 due to the different constraints that act on their growth. In light-limited occidental species, atmospheric CO2 caused the stomata index decrease, whereas in the predominantly water-limited oriental species, increased drought stress and temperature (climatic change) caused stomata index increase. In conclusion, we propose that whereas atmospheric CO2 directly caused a decrease in stomata index in occidental xerophytes, it indirectly caused an increase in stomata index in oriental xerophytes via climate change (increase in aridity, drought stress, and temperature). This study highlights the considerable potential of research based on historical herbarium collections to answer ecological questions, especially regarding climatic change.

plant biology↗