Effects of Flowering Mode and Pollinator Sharing on Reproductive Success in Natural Hybrid of Two Epimedium(Berberidaceae)Species

Mediated by pollenflow,natural hybridization is deemed a crucial factor that propels speciation infloral plants.Despite the fact that the diversity of Epimedium species is concentrated mainly in Southwestern China,the poten-tial impact of interspecific pollination on natural hybridization has yet to be empirically scrutinized.To explore this,we studied theflowering period and the visitors offlowers in three frequently overlapping Epimedium species at Jinchengshan National Forest Park,located in Nanchong,Sichuan Province.Additionally,we performed a ser-ies of pollination experiments to examine breeding systems and hybrid compatibility.Morphologically,Epime-dium pubescens and Epimedium wushanense are clearly distinct and easily recognizable byflower morphology,while the putative hybrid is morphologically intermediate between them.Our observation revealed that E.pub-escens and E.wushanense had 15 days of overlapping anthesis.Both species are self-incompatible and require pol-linator services for successful reproduction.Although their pollinators differ in quantity and species,Lasioglossum sp.(Hymenoptera:Halictidae)visited all three species.Artificial pollination revealed no breeding barriers among the three species,and the resulting hybrid seeds exhibited fertility.The overlapping time offlowering,commonfloral visitors,and compatibility of hybrids may be important factors contributing to successful interspecific pol-lination and speciation for natural hybrid species of E.pubescens and E.wushanense.Consequently,the role of potential interspecific pollination is crucial for hybrid speciation and the evolutionary dynamics of Epimedium species.

Dynamic evolution of Co species and morphological reconstruction on Co-N-C during the nitrate reduction reaction in neutral solution

The electrochemical nitrate reduction reaction(eNO_(3)^(-)RR)is considered an effective approach for converting nitrate-containing wastewater to ammonia.The adsorption and activation of NO_(3)^(-)is the critical step for many materials and the high energy barrier inhibits the continuation of the reduction reaction.The Co nanoparticles encapsulated in the carbon layer we prepared spontaneously react with NO_(3)^(-)and the resulting Co^(2+)is then reduced by electroreduction to Co^(0),which circulates continuously.This resulted in overcoming the energy input required for NO_(3)^(-)adsorption and conversion,thereby increasing the catalytic activity.At the same time,the morphology of the catalyst reconstructed from a dodecahedron to an interwoven nanosheet structure and the increased surface area also gives it better properties.The obtained Co(OH)_(2)@Co-N-C has an excellent eNO_(3)^(-)RR of 2774.7μg·h^(-1)·cm^(-2)with a Faraday efficiency of 81.4%in neutral solution.At the same time,the material-modified electrode can run stably for more than 100 h.Our work provides a new idea for the design of Co-based catalysts for eNO_(3)^(-)RR.

Genetic Differentiation of A and B Chromosomes Between Common Wheat and Wild Emmer as Revealed by RFLP Analysis

To investigate chromosome differentiation of genome A and B between common wheat and wild emmer wheat (Triticum turgidum var. dicoccoides (Koern.) Bowden), the authors conducted a RFLP analysis of the two species using 153 genomic, cDNA and chromosome_specific probes. 75.8% of the probes had detected hybridization polymorphism in at least one of the five restriction enzymes. However, the polymorphic probes were unevenly distributed among different homoeologous groups, between different genomes and in different regions of a single chromosome. Homoeologous group 1 possessed the highest level of polymorphism (96.2%), followed by group 6 and 2 (84.6% and 82.1% respectively). In contrast, only 60%-67% of probes of the other four groups was polymorphic. In most groups the number of probes capable of detecting B chromosome polymorphism was slightly higher than that revealing A chromosome difference (totally 51.8% vs 43.1%). In a single chromosome, RFLP was predominant in the distal region (65.1%) and showed a decreasing trend from the proximal (46.2%) to the pericentric (42.4%) regions. The results suggest that there exists a substantial amount of DNA polymorphism between the A and B chromosomes of common wheat and those of wild emmer wheat, indicating that a considerable degree of genetic differentiation has taken place in the A and B genoms of two species during evolution from wild emmer to common wheat. The extent of the genetic differentiation may vary among different homoeologous groups, between A and B chromosomes and in different regions of individual chromosome.

Reactive oxygen species may play an essential role in driving biological evolution: The Cambrian Explosion as an example

The Cambrian Explosion is one of the most significant events in the history of life;essentially all easily fossilizable animal body plans first evolved during this event. Although many theories have been proposed to explain this event, its cause remains unresolved.Here, we propose that the elevated level of oxygen, in combination with the increased mobility and food intake of metazoans, led to increased cellular levels of reactive oxygen species（ROS）, which drove evolution by enhancing mutation rates and providing new regulatory mechanisms. Our hypothesis may provide a unified explanation for the Cambrian Explosion as it incorporates both environmental and developmental factors and is also consistent with ecological explanations for animal radiation. Future studies should focus on testing this hypothesis, and may lead to important insights into evolution.