Functional and ecological diversification of underground organs in Solanum

The evolution of geophytes in response to different environmental stressors is poorly understood largely due to the great morphological variation in underground plant organs, which includes species with rhizomatous structures or underground storage organs (USOs). Here we compare the evolution and ecological niche patterns of different geophytic organs in Solanum L., classified based on a functional definition and using a clade-based approach with an expert-verified specimen occurrence dataset. Results from PERMANOVA and Phylogenetic ANOVAs indicate that geophytic species occupy drier areas, with rhizomatous species found in the hottest areas whereas species with USOs are restricted to cooler areas in the montane tropics. In addition, rhizomatous species appear to be adapted to fire-driven disturbance, in contrast to species with USOs that appear to be adapted to prolonged climatic disturbance such as unfavorable growing conditions due to drought and cold. We also show that the evolution of rhizome-like structures leads to changes in the relationship between range size and niche breadth. Ancestral state reconstruction shows that in Solanum rhizomatous species are evolutionarily more labile compared to species with USOs. Our results suggest that underground organs enable plants to shift their niches towards distinct extreme environmental conditions and have different evolutionary constraints

Twenty years of big plant genera

In 2004, David Frodin published a landmark review of the history and concepts of big plant genera. Two decades of taxonomic activity have taken place since, coinciding with a revolution in phylogenetics and taxonomic bioinformatics. Here we use data from the World Flora Online (WFO) to provide an updated list of big (more than 500 species) and megadiverse (more than 1000 species) flowering plant genera and highlight changes since 2004. The number of big genera has increased from 57 to 86; today one of every four plant species is classified as a member of a big genus, with 14% in just 28 megadiverse genera. Most (71%) of the growth in big genera since 2000 is the result of new species description, not generic re-circumscription. More than 15% of all currently accepted flowering plant species described in the last two decades are in big genera, suggesting that groups previously considered intractable are now being actively studied taxonomically. Despite this rapid growth in big genera, they remain a significant yet understudied proportion of plant diversity. They represent a significant proportion of global plant diversity and should remain a priority not only for taxonomy but for understanding global diversity patterns and plant evolution in general.</jats:p

Seasonal dynamics of soil microbial growth, respiration, biomass, and carbon use efficiency in temperate soils

Soil microbial growth, respiration, and carbon (C) use efficiency (CUE) are essential parameters to understand, describe and model the soil carbon cycle. While seasonal dynamics of microbial respiration are well studied, little is known about how microbial growth and CUE change over the course of a year, especially outside the plant growing season. In this study, we measured soil microbial respiration, gross growth via 18O incorporation into DNA, and biomass in an agricultural field and a deciduous forest 16 times over the course of two years. We sampled soils to a depth of 5 cm from plots at which harvest residues or leaf litter remained on the plot or was removed. We observed strong seasonal variations of microbial respiration, growth, and biomass. All these microbial parameters were significantly higher at the forest site, which contained 4.3 % organic C compared to the agricultural site with 0.9 % organic C. CUE also varied strongly (0.1 to 0.7) but was overall significantly higher at the agricultural site compared to the forest site. We found that microbial respiration and to a lesser extent microbial growth followed the seasonal dynamics of soil temperature. Microbial growth was further affected by the presence of plants in the agricultural system or foliage in the forest. At low temperatures in winter, both microbial respiration and gross growth showed the lowest rates, whereas CUE (calculated from both respiration and growth) showed amongst the highest values determined during the two years, due to the higher temperature sensitivity of microbial respiration. Microbial biomass C strongly increased in winter. Surprisingly, this winter peak was not connected to high microbial growth or an increase in DNA content. This suggests that microorganisms accumulated C and N, potentially in the form of osmo- or cryoprotectants or increased in cell size but did not divide. This microbial winter bloom and following decline, where C is released from microbial biomass and freely available, might constitute a highly dynamic time in the annual C cycle in temperate soil systems. Highly variable CUE, which was observed in our study, and the fact that CUE is calculated from independently controlled microbial respiration and microbial growth, ask for great caution when CUE is used to describe soil microbial physiology, soil C dynamics or C sequestration. Instead, microbial respiration, microbial growth, and microbial biomass C should be investigated individually in combination to better understand the soil C cycle

Plant traits and associated ecological data from Afromontane grasslands of Maloti-Drakensberg, South Africa

The Afromontane region harbors ancient grasslands with high levels of endemism, now under threat from land-use change, biological invasions and encroachment, and climate warming. As part of an international Plant Functional Traits Course we collected comprehensive trait data in five sites along an elevation gradient from 2,000–2,800 m a.s.l. and in a climate warming experiment at 3,064 m a.s.l. in the Maloti-Drakensberg, South Africa. We sampled 24,405 aboveground and 94 root trait measurements from 171 vascular plant taxa paired with 11 other datasets reflecting vegetation and structure, leaf and ecosystem carbon and water fluxes, leaf hyperspectral reflectance, and microclimatic and environmental data. Our data provide the first recorded trait data for 47 vascular plant species and more than double the trait data coverage from the Maloti-Drakensberg (106% increase). This study offers insights into plant and ecosystem functioning, provides a baseline for assessing impacts of environmental change, builds local competence, and aligns with similar data from China, Svalbard, Peru, and Norway

Data from: Small representative samples capture global vascular plant diversity patterns

Data supporting the manuscript "Small representative samples capture global vascular plant diversity patterns" submitted to New Phytologis

Data from: Small representative samples capture global vascular plant diversity patterns

Data supporting the manuscript "Small representative samples capture global vascular plant diversity patterns" submitted to New Phytologis

DataSheet1_Functional and ecological diversification of underground organs in Solanum.docx

The evolution of geophytes in response to different environmental stressors is poorly understood largely due to the great morphological variation in underground plant organs, which includes species with rhizomatous structures or underground storage organs (USOs). Here we compare the evolution and ecological niche patterns of different geophytic organs in Solanum L., classified based on a functional definition and using a clade-based approach with an expert-verified specimen occurrence dataset. Results from PERMANOVA and Phylogenetic ANOVAs indicate that geophytic species occupy drier areas, with rhizomatous species found in the hottest areas whereas species with USOs are restricted to cooler areas in the montane tropics. In addition, rhizomatous species appear to be adapted to fire-driven disturbance, in contrast to species with USOs that appear to be adapted to prolonged climatic disturbance such as unfavorable growing conditions due to drought and cold. We also show that the evolution of rhizome-like structures leads to changes in the relationship between range size and niche breadth. Ancestral state reconstruction shows that in Solanum rhizomatous species are evolutionarily more labile compared to species with USOs. Our results suggest that underground organs enable plants to shift their niches towards distinct extreme environmental conditions and have different evolutionary constraints.</p

Table1_Functional and ecological diversification of underground organs in Solanum.xlsx

The evolution of geophytes in response to different environmental stressors is poorly understood largely due to the great morphological variation in underground plant organs, which includes species with rhizomatous structures or underground storage organs (USOs). Here we compare the evolution and ecological niche patterns of different geophytic organs in Solanum L., classified based on a functional definition and using a clade-based approach with an expert-verified specimen occurrence dataset. Results from PERMANOVA and Phylogenetic ANOVAs indicate that geophytic species occupy drier areas, with rhizomatous species found in the hottest areas whereas species with USOs are restricted to cooler areas in the montane tropics. In addition, rhizomatous species appear to be adapted to fire-driven disturbance, in contrast to species with USOs that appear to be adapted to prolonged climatic disturbance such as unfavorable growing conditions due to drought and cold. We also show that the evolution of rhizome-like structures leads to changes in the relationship between range size and niche breadth. Ancestral state reconstruction shows that in Solanum rhizomatous species are evolutionarily more labile compared to species with USOs. Our results suggest that underground organs enable plants to shift their niches towards distinct extreme environmental conditions and have different evolutionary constraints.</p